This report presents the results of a successful collaboration between Rod Mahon and Karen Olsen (CSIRO Entomology) and Dr David Heckel (Max Planck Institute for Chemical Ecology, Jena, Germany). For the duration of this project David retained linkages to the University of Melbourne where a significant component of the work was performed.

The project explored resistance to Cry2Ab in the cotton pest Helicoverpa armigera. This species has a remarkable track record of evolving resistance to conventional insecticides and is thus the most likely of the two Helicoverpa species found regularly in cotton (the other is the native H. punctigera) to evolve resistance to the toxins present in transgenic cotton. In other research funded by CRDC, we have found that forms of genes, (alleles) conferring resistance to Cry2Ab toxin in H. armigera are surprisingly common. Because we found the resistance prior to the widespread deployment of transgenic cotton that express this toxin (Bollgard II®), it is clear that the presence of these ‘resistant alleles’ pre-dates man’s activities. Because these alleles are unexpectedly common, (approximately 4 in 100 alleles tested are the ‘resistant’ form) it is important to understand the characteristics of this resistance in order to assess the likelihood that it will become a threat to the long-term efficacy of cotton varieties that express the Cry2Ab toxin as well as a second toxin, Cry1Ac.

We have found that the resistance present in a colony of insects derived from field-collected H. armigera allele is due to a single gene. This fact was established by two quite distinct methods. Firstly, it was found that comparative bioassays of resistant, susceptible, F1 offspring and various backcrosses to the parental (susceptible and resistant) colonies implied that resistance was due to a single autosomal gene. This was confirmed through the study of linkage relationships between genetic variants and resistance. Importantly, the resistance was recessive in the laboratory. If extended to field conditions, this makes this form of resistance less of a threat than would be the case if it was dominant (like most forms of resistance to conventional insecticides).

Of immediate significance to the current varieties of transgenic cotton grown in Australia was the finding that insects seemingly totally resistant to Cry2Ab toxin, are fully susceptible to Cry1Ac, the second toxin in Bollgard II®. Thus it is only during the latter part of the cotton season when Cry 1Ac toxin is diminished in Bollgard II® (similar to the situation in Ingard varieties) that insects resistant to Cry2Ab possess an advantage over susceptible insects. Only under these conditions are the ‘resistant’ alleles likely to increase in frequency. Nevertheless, this window of opportunity is of concern, as if that advantage persists over time, it will lead to a loss of efficacy of this toxin. Clearly careful watch on the frequency of such resistance is important to enable the industry to enjoy the full benefit of any technology that involves Cry2Ab toxin.

CRDC funds an active program to monitor the frequency of resistance to Bt toxins. The most effective means to assess the frequency of resistance is by the use of a simple, but labour intensive genetic system, the F2 screen. Work in this project has identified a likely candidate gene ‘Bre-5’, mutations at which may result in the resistance we have studied. If this information proves to be correct, and can be exploited to develop a DNA means to detect these mutations, this would enable the detection of changes in frequency of the ‘resistant alleles’ earlier, and thus allow more opportunities to respond in a manner that would limit additional changes in frequency before field-resistance became a problem.

This project built on many years of weeds work supported by CRDC and value added to earlier research, while providing strategic information to growers in support of MyBMP, based around updating WEEDpak.

WEEDpak, the guide to integrated weed management in cotton, was a collaborative document written in 2001/2 and released in hard-copy in the spring of 2002. It covered a wide range of weed issues, weed identification material, guidelines for developing an Integrated Weed Management (IWM) approach for cotton, and extensive research findings on the management of specific, hard to control weeds. It was released with 37 weeds and 276 pages of information. WEEDpak has gradually been updated and at the time this project was initiated, included 102 weeds and 612 pages of information, including the Herbicide Damage Identification and Information Guide, a totally new section for WEEDpak. This additional information is only available through the cotton website, where WEEDpak has been the most frequently sought information on the site.

Nevertheless, some strategically important parts of WEEDpak were badly out of date and need updating, such as the IWM Guidelines, Section B2, which were written in the early days of Roundup Ready cotton and primarily covered the conventional cotton production system of the 1990’s. This document needed updating and linking through to the weed components of MyBMP.

The herbicide damage section of WEEDpak is becoming increasingly important, with the spread of cotton into new areas and the growing complexity of the farming system. This guide will need to continue to grow in response to growers seeking information on new herbicides.

The weed threshold work has been a world-class research break-through, but results in research have highlighted limitations to the weed density based approach. Further research will explore the option of going to a weed biomass based threshold to overcome these issues and improve usability.

The Improving energy efficiency on irrigated Australian cotton farms project has developed resources for cotton growers to reduce their energy consumption, updated the cotton industry's myBMP energy module, delivered training, workshops and two energy events, the Big Day Outs. It has also coordinate industry-wide energy use benchmarking and compiled these results and recommendations into a benchmarking report. The Improving energy efficiency on irrigated Australian cotton farms project hhad several objectives and the resulting outcomes have had a significant impact on energy efficiency knowledge, skills, awareness and attitude in the Australian cotton industry. Over 1000 irrigated cotton farms (SMEs) have directly participated in energy efficiency capacity building and awareness raising events held via this project: close to every Australian irrigated cotton SME. This project has developed nearly thirty written information resources and has delivered these directly to 850 irrigated cotton SMEs via thirteen field days, workshops and training sessions, including two large scale events, the Big Day Outs.

This project has captured 213 energy assessments of Australian irrigated cotton businesses and compiled these into an important legacy document: Improving Energy Efficiency in Australian Irrigated Cotton Production Benchmarking Report. This report provides the cotton industry a comprehensive analysis of energy consumption, efficiency and future focus areas to continue to improve energy efficiency on irrigated cotton farms across Australia. This data highlights the significance of diesel as the dominant energy source in the Australian cotton industry - clearly clearly identifying this industry as being significantly different to other broadacre industries in Australia where electricity dominates as the energy supply.

The Level 2 and 3 energy assessments have highlighted irrigation efficiency as an area of particular focus to implement energy efficiency activities on irrigated cotton farms. It is recommended three groups should receive special attention in relation to their energy consumption and pumping costs due to their relatively high consumption of energy – groundwater irrigators; irrigators that use large mixed flow pumps; and irrigators that use heavy tillage. The tractor and heavy tillage trials confirm that up to 20 per cent fuel saving is possible with the correct and appropriate ballasting, tyre pressures, and implement depth control.

The assessments have also highlighted that potential water savings in surface irrigated cotton fields can be 10 to 20 per cent, and 20 to 40 per cent in on-farm storages. As such, every effort should be made to conserve irrigation water at the field level, in distribution systems, and in water storages, as any water lost that has already been pumped is simply lost energy expenditure.

In the most recent Australian Cotton Grower Survey (2014), irrigated SMEs were asked whether they had made any changes to improve the efficiency of water pumping. The three most common actions identified by the respondents were: replacing pumps (56 per cent), replacing pump engines (47 per cent) and increasing attention to maintenance schedules (30 per cent). These activities reflect the emphasis on Level 3 pump efficiency assessments undertaken as part of this project and the relatively high proportion and variation of energy consumption for irrigation.

This report covers the Border Rivers, Moonie and Lower Balonne catchments in the Queensland

Murray Darling Committee, Inc. , (QMDC) management area with the focus of determining priority

groundwater projects. There are three major alluvial groundwater management issues in the QMDC

management area. In the east the Dumaresq River is highly connected to the alluvial aquifers which

are used for groundwater extraction by the irrigation sector. The groundwater model that covers

these alluvial aquifors, and which was used as part of informing the water allocations between NSW

and QLD, needs to be updated. There is new information in the form of longer hydrograph records,

better understanding of river aquifer interactions, longer river flow records and new approaches to

catchment water balance modelling that can all be integrated to give a better catchment water

balance model for input into groundwater management decisions. The main issue for the

cotton/irrigation industry is that over use of goundwater from the Dumaresq River alluvia may

influence river flows, including water released for downstream users.

Given the recent extensive work in the west of the catchment from Goondiwindito Mungindi and the Lower Balonne, it is suggested that the focus should shift to other regions and similar scales of investigation to that done in the Lower Balonne be undertaken in

order to generate similar quality baseline hydrogeological data.

partnering with the Primary Industry Centre for Science Education (PICSE) has been a key strategy for the cotton industry to ensure it has access to, and availability of skilled professionals into the future. PISCE is an industry/university/school partnership designed to stimulate student interest in studying science at university and creating a pathway into real primary industries careers. PISCE brings together Government, RDC's, CRC's and industry investors, and has a national co-ordination centre hosted by the University of Tasmania. Regional Activity Centres (AC's) hosted by universities and industries nationwide implement the PICSE program. The project supports direct engagement with employers so they can experience real professional cotton industry careers in action, and thus supports a stronger employee supply chain.

The PICSE investment has strongly supported workforce development in cotton and has been successful in being able to incorporate aspects of cotton production in able to reach a number of schools (17 in 2014) resulting in 739 student hearing the PICSE/Cotton story. Further the PICSE program has been a strong supporter of the Science and Engineering Investigation Awards and also the annual cotton camp through which 20+ students annually receive much greater immersion into the cotton industry. Many of these students are then linked through to Horizon scholarships which provide further benefit to the industry.

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.

Latest weather news Observed rainfall totals (for the week ending 16 Nov): The Southern Annular Mode: Summary of climate indicators; Rainfall and temperature guidance summary; Madden-Julian Oscillation (MJO); Why won't it rain? ; The impact of Sea Surface Temperatures

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.