This project aimed to identify factors that could substantially influence Bt efficacy in transgenic cotton. Cry1Ac protein concentration in cotton leaves was measured quantitatively using a commercial ELISA assay. Previous research suggested that Bt efficacy was compromised to some extent when environmental stresses were imposed on transgenic plants. Experiments were designed to investigate a range of factors that may affect Bt efficacy, including: crop nutrition, planting density, light intensity, water management, soil type, herbicides, temperature, soil fertility, growth regulators, and cotton cultivars.

Imposing very severe agronomic or environmental stresses on transgenic cotton had the potential to substantially reduce leaf Cry1Ac protein levels, although this did not always occur. Plant health/growth must be severely impaired before substantial reductions in leaf Cry1Ac protein levels occur.

Inadequate N nutrition reduced leaf Cry1Ac protein levels in the first year only, when N fertiliser application had a significant and positive effect on leaf Cry1Ac protein concentration. No effect was observed in the latter two years, despite there being significant responses to N fertiliser application. In some highly sodic commercial cotton fields, severe deficiencies of phosphorus and potassium were encountered that produced leaf senescence and a significant reduction in leaf Cry1Ac protein concentration. Early season zinc deficiency in other fields had no significant effect on leaf Cry1Ac protein concentration. Soil applied potassium fertilisers significantly reduced Cry1Ac protein in Bollgard II leaves.

Planting density had a small significant effect on leaf Cry1Ac protein concentration in the terminal leaves, with higher levels at higher plant density.

Herbicide application had no significant effect on leaf Cry1Ac protein concentrations. Similarly, the application of the plant growth regulator Pix® produced no significant effect on leaf Cry1Ac protein concentration.

Plants subjected to low light intensity (by shading) for one week contained slightly higher Cry1Ac protein concentrations in their leaves than plants subjected to normal light intensity.

Soil waterlogging produced no significant effect on Bt expression in two glasshouse experiments. However, in one experiment, Cry1Ac protein levels in Sicot 289i remained stable, whereas Cry1Ac protein levels in Siokra V-16i continued to decline as the soil dried out. Severe waterlogging of field-grown cotton produced a slight decline in leaf Cry1Ac protein concentration.

Imposing a period of water stress (drought) on Sicot 289RRi and Sicala V-3RRi significantly reduced the leaf Cry1Ac protein concentration.

Glasshouse experiments indicated considerable variability in Bt expression between individual plants of the same cultivar. Sicot 289i plants that expressed either high or low levels of Cry1Ac protein produced progeny with similarly high or low Cry1Ac protein levels.

The cotton industry sees transgenic Bt cotton as the basis for reducing the economic burden of Helicoverpa control and the environmental consequences of insecticide use. Identification of means of realising the potential of Bt cotton would assist the industry in economic terms and possibly help avoid problems of resistance to Cry1Ac genes.

This research has identified that agronomic factors have only small impacts on leaf Cry1Ac protein concentration assayed in cotton leaves. Continued research is required to assist cotton breeders to determine the efficacy of new cultivars.

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Limitations on the availability of irrigation water in eastern Australia has created

interest in the possibility of re-establishing cotton in the Oof

NW Australia, where extensive supplies of water are available and there is potentially the

area of Ord Stage II available for development. This project was undertaken to assess what

agronomic management practices may be required for a dry season cotton production system

in the ORIA.

The ability of plants to compensate after insect damage was investigated and

compared to what happens in traditional cotton growing areas of eastern Australia by

removing fruit, tipping out plants and applying a growth inhibitor (mepiquat chloride).

Mepiquat chloride had no effect on the ability of the plant to compensate for fruit loss while

tipping the plant out (removing the mainstem apex) had a negative impact on yield. Plants

that lost fruit later in the growing season were also unable to compensate and were later

maturing than the controls.

Irrigation scheduling experiments concluded that irrigation scheduling should consist

of irrigating every 21 days/125mm pan evaporation between emergence and mid-squaring,

after 110mm of pan evaporation between mid-squaring and cut-out and at least once between

cut-out and defoliation. The use of growth inhibitors such as mepiquat chloride should be

minimised as there appears to be little benefit in terms of lint yield or quality. It is suggested

that it only be considered on early sown (i.e. pre mid-April) crops and on relatively

indeterminant cultivars such as Sicot 289i and their Bollgard II equivalents.

Wet season cover crops appear to have a place in rotation with dry season cotton

production in the ORIA with dwarf pearl millet or sorghum being the prefered crops. This

should be sown at the start of the wet season and sprayed out after approximately 55 days

after sowing to allow time for thecrop to die and stubble to break down. Roundup Ready

cotton also appears to be a possible weed management option, particularly in a minimum

tillage situation where the cotton can be sown into the wet season stubble and weeds

controlled after the crop has emerged.

Fertiliser trials indicate that 80 kg ha-1 of phosphorus is required when sowing cotton

into land that has previously been unfertilised followed by replacement levels in subsequent

years. If fields are left fallow for extended periods of time (i.e. in excess of one dry season)

plants may have difficulty

Cultivars currently recommended for growing on the ORIA are Siokra V-16i and

Sicot 289i and their Bollgard II equivalents. Both have a high yield potential and produce

satisfactory lint quality. However, variety trials have identified several promising lines with

potential for dry season production on the ORIA. In particular, lines derived from Sicala 35i

Temperature plays a critical and complicated role in the growth and development of cotton. The cool starts to the last three seasons in southern regions have again highlighted of the problems of cold shock and slow crop development rates at low temperature. Low temperatures after sowing increase the time to emergence and reduce seedling vigour often leading to poor establishment, poor early growth and increased risk of seedling diseases. The timing of crop maturity, yield and fibre quality may also be affected. There has also been evidence to suggest that high crop temperatures may negatively impact on crop development.

Much of our current understanding of the impacts of cold temperature on cotton crop growth and development is based on experimental work undertaken by Dr Greg Constable in the early 70’s with cultivars quite different than those used commercially today. It was from these experiments that, the base temperature (12ºC) used in estimating crop development was derived, and the definition of a cold shock (<11ºC) was formulated. Dr Constable acknowledged even at the time there was considerable extrapolation of the information to derive these values the lowest daily temperature tested was 18ºC. His work on cooler temperatures also focussed on early season crop development, as was the need at the time in the Namoi Valley. No specific experimentation on the effects of low temperature has occurred in Australia since then. In addition there has been no definitive attempt to better understand and quantify the effects of temperature extremes on cotton growth and development at other stages and subsequent impact on crop yield (especially with current varieties and agronomic practices, particularly early season insect protection).

This project funding supports the development of a longitudinal research framework, to quantify the impact of investing through the Cotton Research Development Corporation(CRDC) People program. A skilled and capable workforce is known to contribute to the industry’s profitability, sustainability & competitiveness. A key challenge is identifying and establishing metrics through which the industry can assess the value derived from investing in the upskilling and further development of labour and the benefits obtained through increased capacity. Industry is seeking to understand how development programs contribute to attracting and retaining people on farm and the value that employees place on having good working conditions.

The CRDC invests significant funds annually to provide educational opportunities for the industry. The purpose of this project is therefore to contribute to the future decision making about what type of people projects would be expected to reap the greatest benefit based on outcomes achieved todate.

Managing sustainable cotton production is becoming more difficult with the ever-increasing demands for limited resources. To assist with management of cotton crops the Technology Resource Centre (TRC) of the Australian Cotton CRC aims to develop and distribute a range of decision support systems. Some of these systems are computerised eg. entomoLOGIC, nutriLOGIC, and hydroLOGIC, which all come under the banner of CottonLOGIC. The package is accepted as an industry standard for integrated pest management and is widely distributed and used across the industry (registered copies 785 Dec. 1998; currently 1177 Sep. 2002). However, supporting existing products, changing computer systems (eg. Windows 3.11 to Windows 95 and now Windows 98), increasing demands for other computerised decision support tools to be developed and demands by industry to investigate new opportunities (eg. GIS capabilities), have placed significant pressure on the resources of the TRC to meet these needs. Presently, one full time programmer is assigned to developing CottonLOGIC decision support tools, however, much of his time is dedicated in supporting and refining CottonLOGIC to meet users requirements.

Access to further programming support will allow some of the tasks that are necessary for continued progress of decision support to be completed and thus allow the benefits of these tools to be passed on to industry much quicker whilst maintaining support.

Forward weather predictions form the 7th March 2014 to 21st March 2014

With growers now making decisions about how much nitrogen to apply and when, it's worthwhile considering the findings of the CottonInfo N trials: lower upfront N application may help improve NFUE.

Temperature plays many important roles in the growth and development of cotton. Low temperatures after sowing increase the time to emergence and reduce seedling vigour often leading to poor establishment, poor early growth and increased risk of seedling diseases. The timing of crop maturity, yield and fibre quality may also be affected. In addition there is some evidence to suggest that high temperatures may impact negatively on crop development. Research is being conducted to improve our understanding of the impact of temperature extremes on cotton performance. These studies will help improve the precision of both research and management in scenarios where extremes of temperature are likely. This paper describes this ongoing work and presents some results that have enabled better estimates of crop development and attempts to quantity the impact of cold shocks.

The important role that beneficial arthropods play in cotton farming systems is increasingly being recognised across the industry. Many growers and consultants are now growing unsprayed &#39;nursery&#39; crops to generate beneficials on-farm, releasing mass-reared beneficials into crops to bolster their numbers, and using less disruptive insecticides to preserve them. In addition, some are regularly sampling beneficials to use estimates of their abundance and potential impact to make dynainic pest management decisions. An insight into the day to day behaviour of these beneficial species would greatly benefit integrated pest management (IPM) strategies for cotton by increasing our understanding of these biological control agents and our ability to better manipulate them. For example, would maculate ladybird beetles be less prone to an insecticide applied before or after sunrise&#63; Is there an overlapping within plant distribution of green mind nymphs and lynxx spiders&#63; The aim of the present study was to use direct visual observational methods to investigate the behaviour of a common predatory species, the damselbug in the cotton agro-ecosystem.