The question for plant breeders is how do we set priority in a breeding program which meet the fibre quality needs of everyone in the market place while developing competitive high yielding varieties? Fibre quality parameters are complex and plant breeders need to consider various issues when setting priorities and making decisions on fibre quality.

Rapid changes in cotton farming practices and the introduction of new synthetic insecticides and control strategies over the last 10-15 years are likely to have led to significant changes in the species diversity and abundance of beneficial crop canopy insects, soil fauna and soil microflora. However, there have been no studies investigating the effects of these changes in Australian cotton farming practices on beneficial soil fauna since the 1970s and early 1980s (Bishop and Blood 1977; Room 1977; Bishop and Blood 1980). As the Australian cotton industry strives to develop more viable, sustainable and environmentally responsible farming and crop protection practices, detailed and up to date knowledge of the key functional groups of soil fauna and their respective contributions to the cotton agroecosystem performance becomes increasingly essential. The objectives of this baseline research project, which started late in the 1993-94 growing season, were to: (a) develop a soil fauna sampling protocol for cotton agroecosystems, (b) enumerate the principal ecological groups of soil fauna present and (c) for chosen groups, characterise and compare the resultant short term changes in soil fauna biodiversity under different farming and crop protection practices. For the 1995-96 cotton growing season the effects of cotton production on the biodiversity of surface-active soil meso- and macrofauna were studied using pitfall traps and soil cores in single irrigated cotton fields at &quote;Doreen&quote; and at the Australian Cotton Research Institute (Environfeast demonstration field). Here we report on the results for the soil predators component of the 1995-96 season at &quote;Doreen&quote;.

B-type Bemisia tabaci, known commonly as the 'silver leaf white fly' is in Australia and becoming more widespread. The silver leaf whitefly was first detected in Australia in October 1994. It is now established in the Northern Territory, Queensland and New South Wales. This species damages crops through the effects of its feeding, through the effects of the honeydew it produces, which causes moulds on leaves and contaminates cotton lint, and through the spread of geminiviruses. Among the geminiviruses of potential concern to the cotton industry is the cotton leaf curl virus currently causing serious problems in cotton producing regions of Pakistan. Two other whitefly species are often encountered in cotton regions, the native Bemisia tabaci and the greenhouse whitefly, Trialeurodes vaporariorum. A recent brochure &quote;Silver leaf Whitefly: A potential problem for Australian crops&quote;, produced by the CSIRO Division of Entomology, illustrates and describes the differences between these whitefly species(copies can be obtained from Dr De Barro). Overseas, the silver leaf whitefly has rapidly developed resistance to a wide range of insecticides. Given these experiences, and the evidence that the B biotype in Australia is resistant to organophosphate, carbamate and many synthetic pyrethroid insecticides (Robin Gunning, NSW Agriculture pers. comm), sole reliance on chemical insecticides is unlikely to lead to long term control. The common experience in areas where such a situation has prevailed has been the rapid selection of populations that are resistant to the insecticides applied. This is true not only for the conventional insecticides but also for the new novel chemistries such imidacloprid, buprofezin and pyriproxifen. In such circumstances, management becomes extremely difficult. In contrast, in regions where insecticides have not been the sole means of control, natural enemies, both introduced and native, have proven to be effective in reducing damage.

Where does the Australian cotton industry see itself in ten years time? What challenges will it face? How will it address those challenges?

Microplitis demolitor (Hymenoptera: Braconidae) is a mid to late season parasitoid of Helicoverpa spp. larvae. Female M. demolitor prefer to lay eggs in second instar larvae. The host larva is killed before serious damage has been done to the crop and where any reasonable reduction in numbers will be important. Parasitised larvae effectively stop feeding and consume only about 10% of that consumed by healthy larvae (Murray and Rynne, 1992). Numbers of M.demolitor can build up very rapidly in the field. The cotton industry is committed to reducing the use of insecticides because of the economic and environmental costs. With the imminent release of Bt cotton, a very real reduction in insecticide use is expected. Due to reduced expression of Bt toxins in Bt cotton late season (Fitt, 1996), the action of natural enemies should be encouraged at this time. Use of insecticides that disrupt natural enemies should be reduced, however, data on the effects of many insecticides on beneficial insects are lacking under Australian conditions.

The National Farmers' Federation represents a substantial proportion of Australia's 120,000 farming operations around the country, and those farmers represent just about every sector of the rural industry. Through its structure, NFF receives feedback on every major commodity through their representative bodies and State organisations, and policy is formulated to cover the entire industry. Over-riding all of our decisions and action is a vision for Australian agriculture as profitable, environmentally sustainable and competitive. To achieve that vision, our operations are both pro-active and reactive.

Organic matter in soil can supply more than 50% of the nitrogen (N) to cotton crops, but this pool of N supply is dynamic and difficult to predict. Soil bacteria are responsible for mineralising soil organic N and hydrolysing dissolved urea to ammonium. Most plants can take up both ammonium and nitrate forms. However, nitrate is susceptible to leaching and can be denitrified into inert and greenhouse gases. Filterable organic N (dissolved organic nitrogen, DON) is the most readily available form for microbial mineralisation and can also leach. The type and timing of N fertiliser and irrigation may regulate N supply and loss, as the severity of soil drying between irrigation events regulates microbial activity. The ‘Optimising nitrogen and water interactions in cotton’ project investigated how ammonium, nitrate and organic N in soil is affected by urea and DMPP-treated urea fertilisers during wetting and drying cycles of irrigated cotton. DMPP urea is an enhanced efficiency fertiliser that slows the conversion of ammonium to nitrate in soils.

The main objectives of this research were to: (1) investigate how N fertiliser formulations; namely: urea and DMPP-treated urea, and wet/dry cycles affect within- season patterns of soil N supply, (2) identify how well a rapid soil test based on water extraction and measurement of dissolved organic N or potassium chloride-extractable inorganic N species can inform predictions of soil mineralisable N, and (3) suggest how currently available nutrient management DSSs can be improved by improved knowledge of within-season patterns of soil N supply.

The research was conducted in soils established to overhead irrigated cotton on commercial farms over the 2016/17 and 2017/18 seasons in the Darling Downs of south-east Queensland. Soil was sampled after key irrigation or rainfall events, and at critical cotton growth stages. Soil was sampled from outside and inside root exclusion tubes that were placed in the soil to a depth of 300 mm at the beginning of each season,

to monitor the plant-available pools of soil and fertiliser N in the presence and absence of roots, respectively. Novel, low-cost, rapid methods were used to measure nitrate, ammonium and total dissolved N (mineral N and DON). The results were compared with conventional N testing methods for their ability to predict crop N availability.

This project aimed to enhance and support the sustainability of the Australian cotton industry by: providing continued capacity in plant virology expertise and diagnostics, building industry awareness of viral disease threats, and developing preparedness for viral diseases that pose serious biosecurity threats to the Australian cotton industry.

Disease surveys targeting viruses in northern Australia were done over 4 years in areas that may be exposed to possible incursion pathways for biosecurity threats and also in emerging cotton production regions in far northern Western Australia and Queensland. No viruses were detected in cotton production areas of Kununurra and northern QLD. However, six different polerovirus species were detected in other hosts. None of the newly detected poleroviruses are likely to affect cotton but it does indicate there is a diverse range of poleroviruses in northern Australia and emerging cotton production regions may be exposed to new virus threats.

Disease surveys were also done in commercial cotton in Queensland. From 158 disease counts from 35 farms, no symptoms typical of exotic viruses were seen. Generally, there was very low incidence of virus-like symptoms for endemic viruses (Cotton bunchy top virus – CBTV and Tobacco streak virus - TSV) in cotton crops inspected with the exception of a few sporadic disease outbreaks of CBTV. Old volunteer or ratoon cotton appears to be the major source of infection for CBTV moving into crops and as such it is recommended to maintain effective crop hygiene to break the infection cycle and reduce the risk of virus disease outbreaks.

This project has confirmed that two distinct polerovirus species infect cotton in Australia, CBTV-1 and CBTV-2. We found that CBTV-2 is always associated with disease symptoms in cotton while CBTV-1 is not. All symptomatic plants were infected with CBTV-2, either with or without CBTV-1. This will help to focus any future work on the control of CBTV-2 which is likely the only causal agent for disease while it appears that CBTV-1 is most likely non-symptomatic in cotton and of little concern.

Three virus surveys were done in Timor-Leste (East Timor) with the primary focus to establish how common Cotton leafroll dwarf virus (CLRDV) is and what potential threat there may be for incursion into Australia. Gossypium samples were collected from across much of the country and CLRDV was detected from more than 30% of plants tested from several sites. Hence, CLRDV in Timor-Leste was found to be relatively common and widespread in three Gossypium species (G. arboreum, G. barbadense and G. hirsutum). Improved diagnostics developed for CLRDV strains from Timor-Leste, Thailand and other countries will support preparedness for this biosecurity threat.

Other new poleroviruses were also found in Timor-Leste and northern Australia, suggesting there may be natural movement of virus-infected aphids in wind currents from Timor-Leste. This example of potential virus movement may be of concern for the expansion of cotton production in northern Australia.

Host plant resistance has long been a focus of the CSIRO cotton breeding program with emphasis on both morphological (okra leaf, frego bract) and biochemical factors (high gossypol) for resistance to insects. Some of this work was reported at the last cotton conference (Fitt et at 1994). Conventional breeding for pest resistance makes small incremental improvements in the tolerance of varieties to insect feeding and damage. With the advent of genetically engineered cotton the stage is set for quantum leaps in pest resistance, through the introduction of the INGARD Bt gene. However, this does not mean conventional approaches are no longer useful. Ally change to the plant to make it less attractive to pests or more tolerant to damage will only enhance the value of genetically engineered traits by providing a stronger, more stable basis on which to manage those genes. We have continued our work on conventional pest resistance, though now with the added aim of screening breeding lines and other genotypes for resistance to sucking pests like minds, in addition to Helicoverpa and mites. With increasing concern about the possible emergence of Bemisia tabaci Type B (silverleaf whitefly) as a major pest of cotton following its recent introduction to Australia we have also taken the opportunity to evaluate genotypes against whitefly and aphids. This opportunity arose when the unsprayed plots at one of our study sites (Plant Breeding institute, Narrabri) became quite heavily infested with these pests during the 1995/96 season. Here we report the results of these evaluations for the 36 cotton genotypes grown at the PBl site

Achieving reliable, even crop establishment has been identified through the Dryland Cotton Research Association (DCRA) project meetings as one of the major concerns dryland cotton growers face. This issue has gained significant importance with the current commercial varieties available which typically have poorer seed vigour than their predecessors due to the small seed size. Planting, particularly in marginal moisture conditions, is therefore a crucial process in dryland cotton production.

There are various manufacturers producing cotton planters incorporating a range of styles from older style tine planters to single and double disc planters. The goal behind this construction project was to mount different styles of commercial cotton planting units onto a single bar so that the establishment achieved could be compared between units while planting into exactly the same conditions at the same time over a range of soil types and moisture levels.