Browsing by Browse by SEO 2008 "820215 Vegetables"

Graft incompatibility in solanaceous plants was investigated using representative cultivars of tomato (Solanum lycopersicum L), eggplant (Solanum melogena L), and pepper (Capsicum annuum L). Evaluations of the extent of graft (in)compatibility were made by examining survival percentages, fruit yields, and fruit quality in grafted plants. Tomato/pepper (scion/rootstock) and pepper/tomato grafts were considered severely incompatible, and the tomato/eggplant and eggplant/tomato grafts were considered moderately incompatible, when compared with the compatible homo-specific graft combinations of tomato/tomato, eggplant/eggplant, and pepper/pepper. Three, or 3 and 6 weeks after grafting, the dry weights of scions and rootstocks, carbohydrate concentrations in stems above and below the graft unions, scion mineral nutrient concentrations, water potentials of scions, and xylern hydraulic conductivities were measured in the grafted plants. The anatomy of the graft unions was also observed. Growth inhibition and high mortality in tomato/pepper and pepper/tomato grafts (i.e., severe graft incompatibility) was due to discontinuities in the vascular bundles at the graft union, which prevented the translocation of assimilates, mineral nutrients, and water between scions and rootstock. Reductions in fruit yield and/or fruit quality of tomato/eggplant and eggplant/tomato grafts (i.e. moderate graft incompatibility) may have been due to differences in the requirements for assimilates and mineral nutrients between tomato and eggplant. Plant responses to graft incompatibility varied in solanaceous plants depending on the scion and rootstock combination.

It has been commonly assumed that most of the vegetable supply in Port Moresby, the capital city of Papua New Guinea, comes from the PNG highlands and from overseas, because Port Moresby and most parts of Central Province are too dry and infertile for vegetable production. However, contrary to that assumption, a market survey conducted in 2008 found that in fact nearly 90% of vegetable supplies come from Central Province, and particularly from smallholders in peri urban areas around Port Moresby. Demand for fresh produce in Port Moresby has been growing due to population and economic growth and is expected to grow significantly in coming years and into the foreseeable future as a result of the PNG LNG project and other mining and agricultural development projects around the country. The objective of this paper was therefore to assess the potential for increasing vegetable production in Central Province, by carrying out a preliminary feasibility study based on informant interviews, field observations and a literature review.

This study of the Mt Hagen Market was undertaken to assess the socioeconomic impact of the Mt Hagen Market Redevelopment Project that was supported by the Australia-PNG Incentive Fund. Since its completion in late 2006, the Mt Hagen Market has produced significant and positive economic and social outcomes. Impact has extended well beyond Mt Hagen and Western Highlands Province to neighbouring Highlands provinces and coastal areas. The Market provides thousands of people with income-generating opportunities in vegetable and handicraft production and marketing. The majority of these beneficiaries are women, many of whom have become the primary providers for their families and key contributors to their communities. Their social status has improved accordingly and the women reported a sense of empowerment. Despite these highly positive impacts, a lack of support services for market traders and of higher-level aspirations and prospects for young women and street youths was noted. This appeared to be linked to a lack of education and training opportunities. In addition, there are serious issues of over-crowding, law and order breakdown, sales of prohibited store goods, illegal collection and misuse of market fees, and deterioration of market facilities and market services in recent years. The last is mainly as a result of a combination of an increased demand for these services because of the PNG mining boom and of mismanagement. Our main recommendations for improving the Market's performance include: • Separation of fresh produce from livestock and general store goods; • Separation of retail and wholesale markets for fresh produce; • Public awareness and enforcement of market rules and regulation; • Training of market operators in business skills and postharvest management; and • On-going monitoring and assessment of market management by independent third parties.

Blackberry nightshade can vary widely in its growth form, with stems either erect or spreading and occasionally prostrate. Stems are smooth or very sparsely hairy, becoming woody with age. Plants are usually considerably branched with fully mature (flowering) specimens regularly observed at as little as 10 cm in height. Leaves are elliptic to oval with pointed tips, 3 to 7 cm in length, sometimes edged with coarse irregular teeth and wavy margins, and generally dark green to purple-green in colour. Flowers are white with five petals fused at the base with yellow centres, 8 to 12 mm across. The fruit is between 5 and 13 mm in diameter, a shiny berry that is dark green when initially produced and changing to purple-black when ripe.

'Clean and safe' agricultural products are an important issue among consumers, farmers and governments. Many developing countries develop their produce at various points along the 'clean' continuum based on four different production practices related to the use of synthetic chemicals. Organic farming is applied to technologies which do not use chemicals or synthetic fertilisers during production or processing. Safe-use and pesticide-free practices lie between organic and conventional practices, and are possible steps when converting conventional farms to organic farms. The four farming systems are also viewed as a series of 'clean and safe' farming systems, with conventional vegetable (CV) being the least 'clean and safe', safe-use vegetable (SUV) being more 'clean and safe', pesticide free vegetable (PFV) more so again, and organic vegetable (OV) being the most 'clean and safe' system. The main purpose of this paper is to investigate factors affecting the adoption of 'clean and safe' farming systems in northern Thailand. To examine the patterns of adoption based on this continuum notion regarding cleanliness level, we used an ordered logistic regression. Farm-level data on vegetable production were collected from random samples of farms using these technologies in northern Thailand. The results of the analysis of farming system adoption show that the important significant factors are membership of farmers' groups, proportion of female family members working on the farm, location, NGO financial sources, and ownership of freehold land. Thus, in developing more 'clean and safe' farming systems and practices the above factors need to be considered.

Conventional soil management systems (SMS) use synthetic inputs to maximize crop productivity, which leads to environmental degradation. Organic SMS is an alternative that is claimed to prevent or mitigate such negative environmental impacts. Vegetable production systems rely on frequent tillage to prepare beds and manage weeds, and are also characterized by little crop residue input. The use of crop residues and organic fertilizers may counteract the negative impacts of intensive vegetable production. To test this hypothesis, we evaluated the effect of sweet corn ('Zea mays' L. var. 'rugosa') residue incorporation in a corn-cabbage ('Brassica oleracea' L.) rotation on crop yields, nutrient uptake, weed biomass and soil nutrients for organic and conventional SMS in two contrasting soil types (a Chromosol and a Vertosol). Yields of corn and cabbage under the organic SMS were not lower than the conventional SMS, possibly due to the equivalent N, P and K nutrients applied. Macro-nutrient uptake between the organic and conventional SMS did not differ for cabbage heads. Corn residue incorporation reduced the average in-crop weed biomass in cabbage crops by 22% in 2010 and by 47% in 2011. Corn residue-induced inhibitions on weed biomass may be exploited as a supplementary tool to mechanical weed control for the organic SMS, potentially reducing the negative impacts of cultivation on soil organic carbon. Residue incorporation and the organic SMS increased the average total soil N by 7 and 4% compared with the treatments without residue and the conventional SMS, respectively, indicating the longer-term fertility gains of these treatments. Exchangeable K, but not Colwell P, in the soil was significantly increased by residue incorporation. The clayey Vertosol conserved higher levels of nutrients than the sandy Chromosol. Yields under organic SMS can match that of conventional SMS. Residue incorporation in soil improved soil nutrients and reduced weed biomass.

Soil organic carbon (SOC) is the percentage measure of carbon (C) derived from living organisms in soil. Stability of soil organic matter (SOM) can be defined in terms of how easily C and nitrogen in the SOM can be decomposed. Due to the implications in the permanence of SOC during sequestration there is scientific interest in fractionation of SOM into different fractions. A large number of SOM fractionation procedures have been developed to distinguish between SOM to study whether it is liable or recalcitrant to activities of soil microbes. There are physical and chemical fractionation techniques. The former is based on particle size and density of soil samples or combination of the two, and the latter on the reaction of chemical on SOM for the separation of stable SOC. Each fraction of SOC in the laboratory can be commonly determined using wet oxidation by Walkley-Black method and dry combustion by LECO CN Analyzer. With the advancement in chemometric statistical techniques; faster, robust, cheaper and non-destructive methods are emerging. The chemometric statistical techniques do not require any reagents for analysis compared with the wet oxidation or dry combustion methods. Thus, these emerging techniques are highly attractive for studies where a large number of analyses are required. For 'in situ' measurement of SOC, spectral reflectance technology is developed to facilitate instant measurement in the field using the sensors or by remote sensing.

'Tomato spotted wilt virus' (TSWV) affects the production of many horticultural crops worldwide. It was first reported from Kenya in 1999. The occurrence, distribution and genetic diversity of TSWV were evaluated in four tomato production areas in Kenya a decade after this incursion. The awareness of TSWV and its vectors among farmers was assessed through a questionnaire while plant samples including tomato leaves and fruit were collected from diseased and non-diseased plants. The samples were assayed for TSWV using ELISA and reverse transcriptase-polymerase chain reaction, and the resulting positive samples were sequenced. There was less awareness of the virus, its vectors and alternate hosts among farmers, despite the occurrence of the disease for over a decade. A total of 89 of 408 tomato samples tested positive for TSWV. Most of the positive samples came from Nakuru, where the virus was first detected, with only a single positive sample being obtained from Loitokitok and none from Bungoma or Kirinyaga. A phylogenetic analysis based on partial nucleocapsid (N) protein gene sequences suggested that the Kenyan isolates formed a single subgroup nested within a cluster of isolates that came predominantly from Europe. This indicated a single introduction that had undergone limited diversification. The study revealed that the disease has persisted in the area to which it was first introduced but has had very limited dispersal to other areas.

'Tomato spotted wilt virus' (family 'Bunyaviridae', genus 'Tospovirus') is an important virus infecting horticultural crops and is transmitted solely by thrips species. The virus infects a wide range of plant species and presence of 'Frankliniella occidentalis', reported to be the most efficient vector species has complicated its management. TSWV was first reported in Kenya in 1999, causing serious yield losses in tomato production, and has continued to cause sporadic yield losses. This study was undertaken to determine the distribution and genetic diversity of the virus a decade after its incursion into Kenya. The study further evaluated important factors in the epidemiology of the disease and its management.

Thrips have been recognized as primary vectors of tomato spotted wilt virus (TSWV) with 'Frankliniella occidentalis' (Pergande) reported as the most important and efficient vector, while other species such as 'Thrips tabaci' Lindeman also include populations that can vector the virus. A study was undertaken to establish the diversity of thrips and presence of vectors for TSWV in four major tomato production areas in Kenya. The cytochrome oxidase 1 (CO1) gene was used to generate sequences from thrips samples collected from tomatoes and weeds, and phylogenetic analysis done to establish the variation within potential vector populations. 'Ceratothripoides brunneus' Bagnall was the predominant species of thrips in all areas. 'F. occidentalis' and 'T. tabaci' were abundant in Nakuru, Kirinyaga, and Loitokitok but not detected at Bungoma. Other vectors of tospoviruses identified in low numbers were 'Frankliniella schultzei' (Trybom) and 'Scirtothrips dorsalis' Hood. Variation was observed in 'T. tabaci', 'F. occidentalis', and 'F. schultzei'. Kenyan specimens of 'T. tabaci' from tomato belonged to the arrhenotokous group, while those of 'F. occidentalis' clustered with the Western flower thrips G group. The detection of RNA of TSWV in both of these species of thrips supported the role they play as vectors. The study has demonstrated the high diversity of thrips species in tomato production and the occurrence of important vectors of TSWVand other tospoviruses.

Dwarf nettle (Urtica urens) is an annual herbaceous plant, native to Mediterranean Europe, that grows between 10 and 75 cm in height. Figure 1 Life stages, from germination to floweringLeaves are up to 6 cm in length but often 1-3 cm, oval to elliptical in shape, deeply toothed or serrated on the edges, green to dark green, and covered with scattered stinging hairs. Clusters of small, greenish-white flowers form where the leaves join the stems.Dwarf nettle is also known in Australia as small nettle, lesser nettle, or stinging nettle. Vegetable farmers are likely to be very familiar with it where it is found on their farm, and to be well aware of how to identify it. However depending on its stage of growth, it may be possible to mis-identify it as tall nettle (Urtica dioica), native scrub nettle (Urtica incisa) or potentially deadnettle (Lamium amplexicaule), particularly where the plants are recently germinated.

Organic, pesticide free and safe use vegetable farming systems are considered as alternative farming systems. The three vegetable farming systems have different technologies. The produces from the different from farming systems have different 'clean and safe' levels. Economic returns of the three vegetable farming systems are still a question. Thus in this study, economic returns of the three vegetable farming systems were estimated. Farm-level data of organic, pesticide free and safe use vegetable farming were, collected from 377 farms in Chiang Ma province. Conventional vegetable farming was also collected as a benchmark of the study. The results found that vegetable production net incomes included the opportunity costs from household labour and household inputs shows that organic and pesticide free vegetable farms have lower net incomes than that from conventional farms. Safe use vegetable farming systems show similarity to conventional farms. Conversely, when the opportunity costs are excluded from the analysis, organic and pesticide free vegetable farms gain 30 per cent net income over that from safe use and conventional farms. The results could reflect potential of alternative farming systems in supplying clean and safe produce, supporting the environments and absorbing household labour.

Concerns about declining soil organic carbon (SOC) and increased greenhouse gas emissions due to practices such as intensive tillage and bare fallows have encouraged the adoption of practices such as no-tillage, crop rotations and residue retention. However, whilst no-till farming is suited for broadacre crops, it has not been widely adapted for most vegetable production systems. Vegetable production systems, especially organic ones, routinely use tillage to prepare beds and manage weeds. These tillage operations break soil structure and aggregates, which is known to accelerate losses of SOC stocks. Despite requiring multiple tillage operations, the vegetable systems are also characterised by little or no crop residue input, potentially further reducing SOC stocks. The effect of sweet corn ('Zea mays L. var. rugosa') residue management (RM; i.e. incorporation or removal) in a corn-cabbage ('Brassica oleracea' L.) rotation on SOC parameters in two soil management systems (SMS; i.e. organic and conventional) was examined because crop residue incorporation and application of organic fertilisers could be ways to counteract loss of SOC due to tillage in vegetable systems. The principal aim of this thesis was to examine the effect of RM in the two SMS on soil total carbon (TOC) concentrations and stock, soil carbon fractions and microbial biomass carbon (MBC) through a field experiment of a corn/cabbage rotation over two years. A laboratory experiment was performed to separate the confounding factors of SMS in the field experiment, i.e. herbicide and mineral fertilisers in the conventional SMS, and cultivation and organic fertilisers in the organic SMS. To supplement the field experiment, another laboratory experiment focused on how two potentially opposing determinants of TOC, residue incorporation and simulated tillage (sieving), influence the emission of CO₂-C. Although, the research objectives of this thesis are focused on SOC, agronomic and fertility parameters, the essential components of a crop production system, were also considered.

The tenacity of bendiocarb 50 w.p. applied with and without one of six adjuvants at a volume of 125 1/ha to the foliage of brassica plants ('Brassica oleracea germinifera') was evaluated before and after simulated rain by biological assay with 'Plutella xylostella' larvae. Of the adjuvants tested, only Bond Super Sticker and Codacide Oil caused a significant level of improvement in the rainfastness of bendiocarb. Bond Super Sticker and Codacide Oil, individually mixed with bendiocarb were also applied at high volume (600 l/ha) and a suspension of bendiocarb in undiluted Codacide Oil was applied at ultra low volume (5 l/ha). The ultra-low-volume treatment was most effective, providing complete plant protection even after 200 minutes of continuous high-intensity rainfall (36 mm/hour). Codacide Oil may be a suitable adjuvant for bendiocarb at all volumes of application.

This study was focused on the effect of environmental and host factors on the antagonism of Fusarium wilt of tomato, caused by Fusarium oxysporum f. sp. lycopersici (Fol), by non-pathogenic strains of F. oxysporum. Seven non-pathogenic strains of F. oxysporum were isolated and screened for antagonism of Fusarium wilt. Strains F1 and F4 were chosen for further experiments as they reduced disease severity more than other non-pathogens. The best method for applying non-pathogens and pathogens was to inoculate soil with conidial suspension. The non-pathogens reduced seed germination and growth of tomato plants in the absence of the pathogen. In a split root system, non-pathogens F1 and F4 induced resistance of tomato plant against Fusarium wilt although there was no direct contact between the pathogen and non-pathogens. Iron at high and standard concentration in the nutrient solution stimulated induced resistance. However, direct antagonism of Fol by F4 was greatest at low level of iron. Tomato root exudates increased in the vitro antifungal activity of non-pathogens toward pathogens and also increased spore germination of both non-pathogens and pathogens. The components of root exudates including sugars and organic acids influenced the antagonism of non-pathogens against pathogen in vitro. However, sugars and organic acids had little effect on disease suppression in pot trials. In dual culture, using NaNO3 as source of N, the inhibition of Fol by F1 and F4 was decreased at high level of N, whereas at high level of NaNO3 as source of N the antibiotic production increased. Using NH4Cl as source of N at high and low level, the inhibition of Fol by F1 and F4 was increased and the antibiotic production of non-pathogens also increased. In pot trials, the disease severity was less at low N compared with high level of N. In dual culture, at low level of K the antagonistic activity of s F1 and F4 against Fol was improved. However, at high level of K, the antibiotic production of non-pathogens increased. In glasshouse pot trials, non-pathogens improved plant health at low level of K, whereas the growth of non-pathogens was decreased at high level of K. At high level of Ca, the inhibition of growth of Fol by F1 and F4 was decreased. Also at low level of Ca the inhibition of growth of Fol by antibiotic production of F4 was increased. However, the inhibition of growth of Fol by antibiotic production of F1 was increased at high level of K. The inhibition of growth of Fol by F1 and F4 was decreased with high level of iron. The antibiotic production of F1 and F4 inhibited growth of Fol at low level of iron more than at high level. Biological control did not work well at high levels of iron. Further work is needed on the effect of non-pathogens on the growth of plants. More tests should be done on the effect of root exudate on antagonism. Biocontrol agents should be found that can work well at low nutrient levels.

This study was focused on the effect of environmental and host factors on the antagonism of Fusarium wilt of tomato, caused by Fusarium oxysporum f. sp. lycopersici (Fol), by non-pathogenic strains of F. oxysporum. Seven non-pathogenic strains of F. oxysporum were isolated and screened for antagonism of Fusarium wilt. Strains F1 and F4 were chosen for further experiments as they reduced disease severity more than other non-pathogens. The best method for applying non-pathogens and pathogens was to inoculate soil with conidial suspension. The non-pathogens reduced seed germination and growth of tomato plants in the absence of the pathogen. In a split root system, non-pathogens F1 and F4 induced resistance of tomato plant against Fusarium wilt although there was no direct contact between the pathogen and non-pathogens. Iron at high and standard concentration in the nutrient solution stimulated induced resistance. However, direct antagonism of Fol by F4 was greatest at low level of iron.
Tomato root exudates increased in the vitro antifungal activity of non-pathogens toward pathogens and also increased spore germination of both non-pathogens and pathogens. The components of root exudates including sugars and organic acids influenced the antagonism of non-pathogens against pathogen in vitro. However sugars and organic acids had little effect on disease suppression in pot trials.
In dual culture, using NaNO3 as source of N, the inhibition of Fol by F1 and F4 was decreased at high level of N, whereas at high level of NaNO3 as source of N the antibiotic production increased. Using NH4Cl as source of N at high and low level, the inhibition of Fol by F1 and F4 was increased and the antibiotic production of non-pathogens also increased. In pot trials, the disease severity was less at low N compared with high level of N.
In dual culture, at low level of K the antagonistic activity of s F1 and F4 against Fol was improved. However, at high level of K, the antibiotic production of non-pathogens increased. In glasshouse pot trials, non-pathogens improved plant health at low level of K, whereas the growth of non-pathogens was decreased at high level of K.
At high level of Ca, the inhibition of growth of Fol by F1 and F4 was decreased. Also at low level of Ca the inhibition of growth of Fol by antibiotic production of F4 was increased. However, the inhibition of growth of Fol by antibiotic production of F1 was increased at high level of K.
The inhibition of growth of Fol by F1 and F4 was decreased with high level of iron. The antibiotic production of F1 and F4 inhibited growth of Fol at low level of iron more than at high level. Biological control did not work well at high levels of iron.
Further work is needed on the effect of non-pathogens on the growth of plants. More tests should be done on the effect of root exudate on antagonism. Biocontrol agents should be found that can work well at low nutrient levels.

Crop residue management (RM) plays an important role in maintaining soil organic carbon (SOC) in horticulture, especially where annual crop rotations rely on frequent tillage. A trial investigating the short-term effects of sweet corn ('Zea mays' L. var. 'rugosa') residue incorporation on crop yields in a corn-cabbage ('Brassica oleracea' L.) rotation using organic (Org) and conventional (Conv) soil management systems (SMS) was established on 14 December 2009 in two contrasting soil types (Vertosol and Chromosol). The effect of mulched corn residue incorporation on weed biomass production was also studied. Corn was grown under the two SMS and residue was retained (+RES) or removed (-RES) after harvest on 23 April 2010. Cabbage was then grown from 4 May to 14 October 2010, under the same SMS in a three-way factorial design (SMS x RM x soil type). In both systems, equal quantities of macro-nutrients were supplied. Crop yields and weed biomass and apparent electrical conductivity (ECa) of soil were measured. There was no significant difference in total corn biomass for SMS or soil type. However, cabbage yield was significantly greater at the Chromosol site. The SMS x RM x soil type interaction was significant for weed biomass in cabbage, with Org having less weed biomass at the Vertosol site, especially in -RES. The +RES treatment had reduced weed biomass by 20 and 64% in conventional and organic SMS, respectively, in comparison to -RES in Chromosol. Soil ECa was significantly different for soil type only. The reduction of weed biomass in +RES treatment could be attributed to the mulching effect of the incorporated corn residue, the differences in weed seed bank and drainage between two sites. In conclusion, crop yields and soil ECa were not influenced by SMS or RM in short-term, but incorporation of residue in soil reduced weed biomass.

Background and Objective: Seaweeds and seaweed products have been applied in vegetable production systems for many years. Seaweeds and their extracts or by-products may have beneficial effects on vegetable production through increased growth. Possible mechanisms include the nutrient concentration of the seaweed product, the presence of organic compounds such as plant growth regulators (PGR), or through effects on soil processes. Materials and Methods: The effect of application rates and whether mineral nutrients alone can account for plant growth responses, was assessed by using two commercial seaweed products (Maxicrop® and Seasol®) applied at four rates (0, 1, 2, 4 ×recommended rate) as well as ashed product and an equivalent mineral fertilizer treatment with the same nutrient content as the recommended rates for each seaweed product. Results: The results show that both Maxicrop and Seasol can significantly increase crop performance. Maxicrop increased shoot biomass, root biomass and leaf chlorophyll content above that of the mineral treatments by 66, 47 and 9%, respectively, while Seasol increased root biomass only (by 50%). By ashing the seaweed product or preparing a mineral-only nutrient solution, we have confirmed that seaweed products can improve plant growth beyond that of mineral nutrients alone. However, seaweed fertilizer products with very low nutrient analysis may be unlikely to improve plant growth without supplementary nutrient additions from other sources. Where the nutrient content is adequate, growth may be greater than equivalent mineral nutrient applications. Conclusion: These pot trials demonstrate the potential value of some seaweed fertiliser products for nursery production and other containerised plant systems. Further research is required to clarify the role of various plant growth regulators, biostimulants and soil conditioning compounds.

The Dobra family are third-generation vegetable growers based in the Gingin district, approximately 90 km north of Perth, Western Australia.Maureen and Barry Dobra have over 40 years experience growing a range of vegetables, including carrots, beets, turnips, radish, lettuce, broccoli and rockmelons. Their children Deanne, Simone, Kevan and Peter, and now two grandchildren are involved in the business.

The Schreurs family have been growing vegetables in the Cranbourne district, approximately 50 km south-east of Melbourne, since the 1950s. Originally renowned for introducing Dutch carrots into the Australian market, Schreurs & Sons has now diversified into growing a variety of vegetable crops. Today, Schreurs & Sons own five farms in the outer Melbourne suburbs of Clyde and Devon Meadows, totalling approximately 550 hectares. Across these farms, approximately 400 hectares are dedicated to vegetable production. The business employs about 180 staff, rotating across the five farm sites depending on need for ground preparation, planting and sowing, crop management, and harvest activities.

Fat hen (Chenopodium album) is an erect annual herbaceous plant, native to Europe, that grows between 0.2 and 2 metres in height, and has ridged striped stems. Leaves are between 2-6 cm in length, oval to trowel-shaped, edged with teeth or irregular lobes. They vary in colour but are often blue/green or grey/green, and may have a mealy (powdery) surface. Flowers are green and white, in small clusters and continuous along the stem. The seed remains enclosed by flower segments at maturity.Fat hen may also be known in Australia as white goosefoot or common lamb's quarters. Nearly all vegetable farmers will be well aware of fat hen and how to identify it. However in some cases, depending on stage of growth and experience in identification, some other common annual heavy-seeding weeds of Australian vegetable production may be mis-named as fat hen, including nettle-leaf goosefoot (Chenopodium murale), crumbweeds (Dysphania spp.), amaranth (Amaranthus spp.), potato weed (Galinsoga parviflora) or blackberry nightshade (Solanum nigrum).

The overall aim of this project was to identify constraints that impede smallholders' capacity to adopt innovative farming practices and better marketing strategies to improve farm-level productivity and profitability. The key objectives of this SRA were: • To understand the technological, institutional and capacity constraints that cause a wide range of differences in productivity outcomes for smallholders. • To identify the main factors influencing productivity improvement for farmers and the kind of policy measures can be adopted to improve these criteria. • To review the marketing strategies adopted by smallholders to maximize their returns and, thus, identify policy options to accelerate market reform. • To evaluate: (a) the agricultural support strategies implemented by the government and donors to increase farm productivity, and (b) the capacity of these strategies to support productivity development. This research that addressed these objectives involved several stages, including: (a) reviewing the literature and analysing the existing policies to promote pro-poor agricultural growth; (b) developing survey tools and econometric methods to measure the main sources of horticultural sector performance and various constraints that are hindering smallholders' productivity and profitability; (c) policy workshop(s) and consultation with stakeholders including academics, government officials, international donors and industry representatives; (d) focus-group interviews with smallholders to identify priority area for reform; and (e) dissemination of research findings through conference participation and policy briefs.

This dataset consists of eight tabs (the first four relating to Chapter 2 and the remaining four relating to Chapters 3, 4, 5, and 6 of my thesis). All data related to this thesis was collected online from the Web of Science and Scopus search engines (Chapter 2), the CropPol and Rader et al. 2020 public databases, and in the field from Griffith, New South Wales, Australia (Chapters 3, 4, and 5), from the East-North Coast of New South Wales, Australia (Chapter 6), and from Northern Tasmania, Australia (Chapter 6). Each tab has an excel spreadsheet with data from each thesis research chapter, and the content of each tab is explained below: Chapter 2.1: A review of the life history needs of the larval and adult stages of crop flower-visiting flies (Diptera). This dataset consists of family, genus, and species names extracted from public pollination databases ('CropPol' or 'Rader et al. 2020'), the total number of searches the species name received from Scopus and/or WOS (Web of Science), whether the information for the diet and habitat needs were found ('Accessible' or 'Inaccessible'), the total number of larval and adult feeding guilds the fly may utilize ('Unknown', 'One', 'Two', 'Three', 'Four', 'Five', or 'Six'), whether the fly utilizes the same feeding guilds in both active developmental stages of life ('Unknown', 'Different', or 'Same'), and finally the dataset in which the species name was extracted from ('CropPol' or 'Rader et al. 2020'). Chapter 2.2: A review of the life history needs of the larval and adult stages of crop flower-visiting flies (Diptera). This dataset consists of adult fly life history information extracted from reviewed articles, such as the feeding mechanism (e.g., chewing decaying animal flesh, sucking blood, etc.), habitat, and feeding substrate of specific crop flower-visiting fly species. The quality of this extracted information is placed in two categories ('Validated in experiment', or 'Inferred (by authors)'). Chapter 2.3: A review of the life history needs of the larval and adult stages of crop flower-visiting flies (Diptera). This dataset consists of the larval fly life history information extracted from reviewed articles, including the feeding mechanism (e.g., chewing decaying animal flesh, sucking blood, etc.), habitat, and feeding substrate of specific crop flower-visiting fly species. The quality of this extracted information is placed in four categories ('Validated in experiment', 'Inferred (by authors)', '(Validated by) Expert', and 'Unable to access'). Chapter 2.4: A review of the life history needs of the larval and adult stages of crop flower-visiting flies (Diptera). This dataset consists of the data on the biogeographic host range of the species and was extracted from species catalogues, manuals, and websites (‘References’) managed by experts in the field of Dipterology. One species may occupy more than one biogeographical region. Chapter 3: Floral visitation surveys of insect visitors of hybrid seed carrot (Daucus carota subsp. sativus) crop plants. Surveys were conducted up to three times a week during full bloom (22 November to 5 December 2021) at six sites throughout the day (05:00 to 17:00). Surveys were conducted along two, 10 m transects: one along the edge of the carrot field and an additional walk in the middle (> 30 m into the field). All transects were conducted walking slowly (1 m per minute when possible) between two rows of carrot plants (either ‘Male’ and ‘Female’ or ‘Monoecious’ and ‘Monecious’). The temperature and relative humidity was recorded using Kestrel® Drop D2 data loggers permanently deployed in a shaded location within, or nearby, all study sites. All insects were identified to the lowest taxonomic level using dichotomous keys. Chapter 4: Deploying habitat to support the immature life stages of eristaline flies (Syrphidae) in hybrid seed carrot crop agroecosystems. In a paired experimental design, two habitat pools filled with substrates (‘carrot’ and ‘soil’) intended to attract eristaline flies were deployed at 7 sites. The pools were placed between 15 November to 24 November 2021 and left to decay for 12 to 21 days. Surveys of the immature life stages (‘eggs’ and/or ‘larvae’) were identified and counted within the pools. The state of the larvae (‘first instar’, ‘second instar’, ‘third instar’, or ‘dead’) as well as the location where batches of eggs were laid within the deployed habitat were determined. Chapter 5: Effectiveness of fly and bee pollinators at pollinating hybrid carrot plants grown for seed. This dataset consists of stigmas collected after a single visit by one pollinator species. The first column is date the replicate was collected, the second column is the pollinator species, the third column is the duration of time in seconds the pollinator spent visiting the replicate, the fourth column is the number of stigmas mounted on the slide, the fifth column is the number of pollinated stigmas (at least one pollen grain touching the stigma), and the sixth column is the total number of pollen grains touching the carrot stigmas. Chapter 6: Efficiency of fly and bee pollinators at pollinating blackberry (Rubus fruticosus) and raspberry (Rubus ideaus) crop plants. This dataset consists of berries harvested after single visitation (one visit to a flower), unlimited visitation (allowed access to flowers in a small cage setting), and open pollination (scale of a farm polytunnel) treatments under field conditions. The first column is the unique pollinator ID, the second column is the pollinator species, the third column is the type of trial (‘Cage’ or ‘Field’), the fourth column is the weight of the harvested fruits, the fifth column is the number of drupelets per fruit, the sixth column is type of defect found in the fruit (’None’, ‘Progressive’, or ‘ Critical’) as per industry standards, and the seventh column explains the type of defect seen in the fruit (if any). 



Food processing using local materials has the potential to create employment and income-generating opportunities for smallholder farmers and rural communities. In Papua New Guinea (PNG), the food manufacturing sector is small, and is dominated by a small number of foreign companies using primarily imported ingredients. To address these issues, the 'Development of a food processing and preservation industry' was identified by the PNG government as one of the priority programs for agricultural development in the National Agricultural Development Plan. The objective of this study was to assess the challenges and opportunities for developing a locally owned food processing sector in PNG using sweetpotato as a test case. The research involved an extensive literature review of sweetpotato processing research and development activities in PNG, as well as in China and Africa where such research and development activities have been the most extensive. Results showed that, given the current environment, promoting sweetpotato processing into commercially viable enterprises will be challenging. However, if the PNG government is determined to develop a food processing industry, sweetpotato processing can be used as a pilot both to build research and development capacity for food processing and to investigate whether and how an efficient food processing industry can be developed.

The response of 'Sclerotinia sclerotiorum' , the causal agent of stem rot of oilseed rape ('Brassica napus'), to toxic volatiles produced by the glucosinolate-myrosinase system was studied. Mycelium plugs were exposed to inoculated leaf discs of oilseed rape cultivars and two related species, black mustard ('Brassica nigra') and white mustard ('Sinapis alba'). Growth of exposed colonies was inhibited by more than 87% compared with controls. Despite inhibition of exposed fungal colonies, the fungus continued to grow in infected tissue. Repeated exposure of the fungus to hydrated mustard powder (which contains both glucosinolates and myrosinase) or synthetic isothiocyanates (ITCs) resulted in growth inhibition decreasing from initial levels of up to 80% to insignificant levels after 2–3 days, suggesting that 'S. sclerotiorum' has the ability to adapt to volatiles during the infection progress. This adaptation was studied by investigating induction of glutathione S-transferase-like genes identified from the 'S. sclerotiorum' genome. Three genes, with locus numbers SS1G_07195.1, SS1G_01918.1 and SS1G_10295.1, appeared to be up-regulated following exposure of 'S. sclerotiorum' to mustard powder or allyl ITC. A fourth gene, SS1G_07319.1, appeared to be down-regulated. In addition, glutathione S-transferase catalytic activity in crude mycelium extracts was doubled following 48 h of exposure to mustard powder volatiles. This adaptation could allow 'S. sclerotiorum' to parasitize tissues of 'Brassica' species despite the production of toxic metabolites.

The POTATOPLAN project aims to adapt comprehensive genetic evaluation systems used in forest tree and livestock breeding to potatoes. These systems use Best Linear Unbiased Prediction (BLUP) to incorporate all measurements from all relatives and correlated traits to best predict the additive and total genetic values of all genotypes for all traits. This enables optimal selection of genotypes for breeding and deployment as any genotype at any stage of testing can be compared with any other, including commercial varieties. The method can remove biases due to natural and artificial environmental variation while accounting for GxE, genetic trends over time due to selection, differences in data amount and quality, and varying sampling procedures. The models have been adapted to potatoes by estimating additive genetic effects using an additive relationship matrix that recognises the polyploid nature of most potato varieties. Family merit score counts (number of selected progeny) are converted into a binary selection trait for the genotypes in the family, with a value of 1 for selected named progeny and 0 for unselected progeny. This trait is used to predict the value of the selected progeny for all traits that contribute to the merit score through the genetic correlations determined on an experimental basis. Measurements of genotype performance using different plot or sample sizes is accounted for by using weighted analysis with the individual plant or standard sample size error variance as the reference point. These approaches should allow the more widespread adoption of BLUP methods in potato and other crop breeding. POTATOPLAN also includes a comprehensive database of pedigree, measurements, trial designs, genetic and other model parameters, and resultant genetic values to make them useable for breeders and growers.

Soil organic carbon (SOC) is reduced in annual horticultural systems due to accelerated CO₂emission from the frequent and intensive tillage required to prepare beds and manage pests. Conversely, crop residue incorporation has the potential to counteract the loss of SOC. We hypothesised that vegetable systems could be made more resistant to SOC loss by including a high-residue grain crop such as sweet corn ('Zea mays var. rugosa' L.) in the rotation. We incubated two Australian soils, an Alfisol and a Vertisol, in plant-free sealed chambers with a ± corn residue treatment and soils either sieved/disturbed or not to simulate tillage. Carbon dioxide-carbon (CO₂-C) flux was measured using air samples collected at 24 hours before , and 1, 120, 240 and 360 h after simulated tillage. Residue incorporation had a larger effect on CO₂-C flux than tillage for both soil types. The tillage x residue interaction accounted for 40% of CO₂-C flux; the effect of residue was highly significant but tillage alone was not significant. The effect of simulated tillage on residue incorporated soil was most stimulatory and the treatment without residue or without simulated tillage was the least stimulatory to CO₂ emission. Residue effects were 22% higher in the Alfisol compared with the Vertisol whilst tillage effects were 26% higher in the Vertisol than in the Alfisol. The Vertisol was more resistant to CO₂ losses than the Alfisol after disturbance as the gas fluxes stabilised more rapidly following soil disturbance. In summary, residue incorporation and tillage interactions were a function of soil type, and fine-textured soils such as the Vertisol may be less prone to CO₂ losses than lighter-textured soils.

The Market Development Project (MDP) was initiated by the Fresh Produce Development Company (FPDA) of Papua New Guinea (PNG) in 2006. The project involved FPDA acting as a wholesaler, buying fresh produce from farmers in the PNG Highlands and delivering it to supermarkets in Port Moresby and to a mining town, Tabubil, in the Western Province. In 2010 a review was undertaken to assess MDP's performance over the four years it had been in operation: what it had achieved and what it had not; how cost effective it was; whether and how it could have been done better; and whether a government agency should be involved in a seemingly private wholesaling business. The MDP was set up to link farmers to markets. It aimed to provide farmers with secure markets and stable prices; generate market information which the agency could use to develop policies and strategies; provide a learning ground to educate farmers and the staff to become commercial and market-oriented; and encourage farmers to save money through the establishment of bank accounts. The study showed that some of the objectives have been achieved, for example, gaining practical experience in marketing, building capacities of farmers and staff, establishing bank accounts and encouraging savings for some farmers. However, these achievements were not significant relative to the time and substantial resources that had been invested in it. More importantly, it failed to make significant inroads into addressing known supply chain issues of poor transport, poor post-harvest handling, and inconsistent supply. Our findings suggest that more effort should have been given to staff and farmers' training, gathering information on costs of production and marketing and identifying and addressing supply chain issues. In addition, a workable monitoring and evaluation framework should have been put in place so that problems and deficiencies in the design and operation of MDP, most notably its pricing structure and quality control measures, could be identified and rectified as soon as they occurred. The case of MDP demonstrates clearly that administered pricing (as is MDP pricing) is no substitute for the free play of market forces and farmers' interests can be better served by government acting as a facilitator, rather than as an interventionist.

The unique and somewhat problematic challenges of marketing fresh fruits and vegetables have received attention from a variety of perspectives in recent years. The role that price plays for consumer purchases of them is complex, and will depend on the buyer, product and situation. This article discusses the dimensions of individual product differences in terms of amount spent, whether purchased as a treat and whether the products are seasonal. These differences and their implications for buyer's attention to price are investigated. The major implication arising from this research is that increased sales of fresh fruits and vegetables are likely to be achieved by keeping the price as low as possible for products for which buyer attention to price is high, that is, products that are treats and seasonal. Further, retailer profitability will be optimised if, in conjunction with the previous suggestion, higher gross margins are included for products where buyer attention to price is low, that is, staples and non-seasonal products.

Marshmallow (also sometimes called ‘small-flowered mallow’ or ‘little mallow’) is an annual sprawling herb, native to the Mediterranean region, with a single long taproot. It can grow up to 1.2 m in height and 2.1 m in width.The plant is woody at the base. Leaves are dull dark green and surrounded with scalloped lobes and radiating veins. They are variable in size, at 2 to 12 cm wide and 1 to7 cm long. Flowers emerge in clusters, with five notched petals white to pale pink, around 5 mm in length. Fruit is a round capsule approximately 1 cm in diameter, containing between 8 and 12 non-hairy seeds. When ripe, these change colour from green to dark brown. There are several other Malva and related species present in Australia, many of which are also weeds of disturbed sites such as cultivation, gardens, drains and roadsides but less prevalent than marshmallow. These include: Tree mallow, Malva arborea; Musk mallow, Malva moschate; Dwarf mallow, Malva neglecta; Mallow-of-Nice, Malva nicaeensis; Cretan mallow, Malva pseudolavatera; Tall mallow, Malva sylvestris; Spiked malvastrum, Malvastrum americanum; Red-flowered mallow, Modiola caroliniana.

Nutgrass (Cyperus rotundus) is a highly variable perennial sedge.Although not a grass species, the name 'nutgrass' is commonly used for this plant in Australia. It is also sometimes called 'nutsedge'. It usually grows to between 20 and 50cm tall, and occasionally taller under favourable conditions. Stems are erect, smooth, not branched, and triangular in cross-section. Leaves are dark to bright green, glossy, up to 2-6 mm wide and 20cm in length, grass-like, and have a prominent vein on the underside. They are slightly serrated, and generally shorter than the plant stems. There are up to 20 leaves per plant, mostly emerging in three rows near ground level.The flowers are a cluster of brown to reddish-brown/purplish-brown narrow flattened spikelets of varying lengths. These tend to emerge from a common point on several slender flower stalks. Beneath the ground, the plant features a network of bulbs, roots, rhizomes, and multiple tubers in chains (over six per chain in some circumstances). Tubers are dark brown to black, irregularly shaped and up to 2 cm in length when fully grown. Each tuber has multiple buds, most of which remain dormant and are available as a reserve in the event the active shoot is destroyed. Dormant tubers can commonly persist in the soil for 3-4 years, but remain viable for up to 10 years in ideal conditions. Individual plants form a basal bulb, mostly within 7-18 cm of the soil surface. This basal bulb contains the plant growing point. The fibrous root system can extend up to 1.2 metres below the soil surface. Because the growing point remains in the basal bulb, leaves can regrow easily after being severed at the soil surface.

The soil nutrient status (0–10 cm) of two farming systems (organic (OF) and conventional or integrated (CF) vegetable farms) at three locations (Gatton, Stanthorpe and Dorrigo) was examined for the suite of fertility indicators. A wide range chemical parameters and microbial biomass carbon were similar between farming systems, in contrast to some broad-acre organic systems. Examination of farm management records revealed substantial overlap between nutrient inputs at all localities with CF systems also receiving organic inputs, e.g. green manure and composts. Labile soil phosphorus levels were high (>100 mg kgˉ¹) in both farming systems, at all sites. The nutrient levels of these intensive vegetable production systems revealed potential environmental risks especially in sandy well drained soils and should be monitored accordingly. Future research could be focused on crop management measures to mitigate runoff and deep drainage loss of nutrients from these farms.

Pigweed (Portulaca oleracea) is an annual, succulent herb. It is native to either South America or North Africa, and features a thick tap root with many fibrous secondary roots, forming a prostrate mat of up to 60 cm in diameter. The stem of pigweed is often reddish, succulent, and commonly with several degrees of branching observed from the main stem. Leaves are alternate and are often clustered at branch tips. They are smooth, succulent, thick, shiny, and are narrow at the base with broad, rounded ends, ranging from 2 to 13 mm in width and 4 to 28 mm in length. Flowers are pale yellow, around 4 mm long, and comprised of 4 to 6 petals. Fruit is a globular pointed capsule, 4 to 9 mm in diameter, and contains many tiny brown to black seeds, which are shiny and 0.5 to 0.8 mm in diameter. Pigweed is also sometimes known as 'purslane'. It is a distinctive weed species and most vegetable farmers will be familiar with it, however it may be possible to confuse it with 'giant pigweed' (Trianthema portulacastrum), particularly soon after germination. Also known as black pigweed, this species is considered a native of tropical areas, and in Australia is largely found in the Northern Territory, Queensland, and northern New South Wales. As an adult plant, giant pigweed may be distinguished from pigweed by its more rounded, crinkled leaves and pink flowers.

Seaweeds and seaweed products have been applied in vegetable production systems for many years. This is because seaweeds have beneficial effects in vegetable production systems. However, the mechanism by which seaweed can elicit the growth and development response is still not fully understood. Mineral nutrient concentrations are commonly too low to be effective, and plant growth regulators (PGR) have been suggested as a causal factor. PGR activity in two seaweed products (Maxicrop® and Seasol®) was investigated using field pea ('Pisum sativum' L.) bioassays. Treatments included a control, standard concentrations of the seaweed products, ashed seaweed products, auxin, cytokinin, gibberellin and mineral nutrients (matched to each seaweed product). The results obtained show that the seaweed products have potential plant growth regulator activity rather than a mineral nutrient effect alone. Ashing reduced the root growth effect of Seasol® but not Maxicrop®. Seasol® performed better than Maxicrop® based on the root and shoot length.

We analyzed the productivity levels of smallholder farms in northern Thailand practicing different 'clean and safe' vegetable farming systems or conventional vegetable (CV) production. 'Clean and safe' farmers are categorized into three groups based on their use of synthetic chemicals: organic, pesticide-free and safe-use. Farm-level data on vegetable production were collected from random samples of farms operating these farming systems. A standard stochastic production frontier model and a metafrontier model were estimated for each system to obtain estimates of technical efficiency (TE) with respect to their cohorts, metatechnology ratios (MTRs, showing the extent of technology gaps between farming systems) and overall productivity measures. Productivity levels were found to vary moderately between farming systems. 'Clean and safe' farms achieved a higher mean TE score than conventional farms, indicating a more efficient use of inputs in producing a certain level of output within their system. However, their MTRs were significantly lower than those of conventional farmers, indicating greater production technology constraints because of the need to conform to strict guidelines. All four farming systems had at least one farmer who could overcome the technological constraints to achieve the highest possible output regardless of the technology used. Effective assistance providers were found to be crucial for farmers to achieve high productivity in the organic farming system. Improvements are needed to raise low productivity levels through technology transfer, value chain improvement and farmer capacity in production and marketing. The required improvement strategies differ among farming systems.

Short and variable vase life of cut 'Acacia holosericea' foliage stems limits its commercial potential. Retrospective evaluation of factors affecting the vase life of this cut foliage line was assessed using primary data collected from 30 individual experiments. These data had been collected by four different researchers over 17 months, from late Summer to mid Winter across two consecutive years. Vase life data of cut 'A. holosericea' stems held in deionised water (DIW) was analysed for general vase life variation and to define the most influential factor affecting vase life of the cut stems. Meanwhile, vase life of cut stems exposed to various chemical and physical postharvest treatments was analysed using meta-analysis to evaluate their efficacy in prolonging vase life of the stems. The overall mean vase life (±standard deviation) of cut 'A. holosericea' stems was 6.4 ± 1.2 days (n = 30 trials). Longer vase life of ≥7 days was obtained from cut stems harvested at vegetative and flowering stage, which was between Summer and Autumn. Cut stems harvested at fruiting stage, between Winter and Spring displayed shorter vase life of ≤5.5 days. Mixed model analysis indicated that vase life variation of the cut stems was mostly determined by season (P<0.001). In averaged, postharvest treatments increased vase life 1.4-fold compared to stems in DIW, with 68.32% had a large positive treatment effect size (d). Among the treatments, nano silver (NS)and copper (Cu²⁺) were the most beneficial to vase life. Retrospective analysis was found to be beneficial for identifying conditions and targeting practices to maximise the vase life of cut 'A. holosericea' and,potentially for other species.

A major challenge of the 21st century is to produce more food for a growing population without increasing humanity’s agricultural footprint. Urban food production may help to solve this challenge; however, little research has examined the productivity of urban farming systems. We investigated inputs and produce yields over a 1-y period in 13 small-scale organic farms and gardens in Sydney, Australia. We found mean yields to be 5.94 kg⋅m⁻², around twice the yield of typical Australian commercial vegetable farms. While these systems used land efficiently, economic and emergy (embodied energy) analyses showed they were relatively inefficient in their use of material and labor resources. Benefit-to-cost ratios demonstrated that, on average, the gardens ran at a financial loss and emergy transformity was one to three orders of magnitude greater than many conventional rural farms. Only 14.66% of all inputs were considered “renewable,” resulting in a moderate mean environmental loading ratio (ELR) of 5.82, a value within the range of many conventional farming systems. However, when all nonrenewable inputs capable of being substituted with local renewable inputs were replaced in a hypothetical scenario, the ELR improved markedly to 1.32. These results show that urban agriculture can be highly productive; however, this productivity comes with many trade-offs, and care must be taken to ensure its sustainability.

The soil phosphorus (P) status (0-10 cm) of two farming systems (organic (OF) and conventional (CF) vegetable farms) at two locations (Gatton and Stanthorpe) was examined amongst a suite of soil fertility indicators. The P status was similar between farming systems, in contrast to some broad-acre organic systems. Examination of farm management records revealed substantial overlap between P inputs at both localities with CF systems also receiving organic inputs, e.g. green manure and composts. A statistical analysis of the effects of different inputs also indicated that P fertility did not vary significantly between farms. Soil P levels were medium to high across farm types indicating a potential environmental risk for vegetable producers particularly in sandy well drained soils. The three methods of extraction Colwell, Olsen and Resin were well correlated with each other and produced similar results indicating the similar nutrient pools exist between farming system.

An experiment aimed to examine the effect of aqueous extracts of three weed species on soybean roottip- cell mitosis has been carried out at the Laboratory of Plant Physiology and Biotechnology. Department of Agronomy and Soil Science, University of New England, Australia. Aqueous extracts of fresh weed material ('Amaranthus Cyperus rotundus' and 'Paspalum dilatation') at the concentration of 25% ( w/v) were added to the germination medium of soybean seeds cultivar Banjalong, Melrose, and Valiant. The germination was conducted at a growth cabinet with 25°C and total darkness. All experimental units were arranged in a completely randomized design with 5 replication. Radicles (roots) from the germinating soybeans were harvested when they were about 1 – 1.5 cm long. The soybean root tips were used to observe the mitotic index following a series of hydrolysis and staining process. Results indicate that aqueous extracts of the weeds reduced cell division of the soybean regardless of the cultivars. This contributes to the understanding of the modes of action of the allelopathic effect of the weeds. 'Amaranthus powellii' had the most inhibitory effect to the soybean cell division.