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The article discusses the applied sciences of food and fibre production. Topics mentioned include the shortage of people in the qualified workforce of the agricultural sector, the estimated number of people around the world being fed by Australian agriculture as of September 2016, and the vision of an Australian community by the Primary Industries Education Foundation Australia.

Genetic diversity for traits such as fibre quality or disease resistance to microorganisms is limited in the elite cotton germplasm; consequently, cotton breeders are looking for novel alleles in the secondary or even in the tertiary gene pools. The wild Australian Gossypium species (tertiary gene pool) represent an alternative source of novel alleles. However, to use these species efficiently, enabling tools are required. Chromosome-specific molecular markers are particularly useful tools to track the transmission of this exotic genetic material into the cultivated cotton during introgression. In this study, we report the construction of a genetic linkage map of the Australian wild C-genome species Gossypium sturtianum. The map, based on an F2 population of 114 individuals, contains 291 AFLP loci. The map spans 1697 cM with an average distance of 5.8 cM between markers. To associate C-genome chromosomes with the A and D subgenomes of cultivated cotton, 29 SSR and RFLP-STS markers were assigned to chromosomes using cultivated cotton mapped marker information. Polymorphisms were revealed by 51 AFLP primer combinations and 38 RFLP-STS and 115 SSR cotton mapped markers. The utility of transferring RFLP-STS and SSR cotton mapped markers to other Gossypium species shows the usefulness of a comparative approach as a source of markers and for aligning the genetic map of G. sturtianum with the cultivated species in the future. This also indicates that the overall structure of the G. sturtianum linkage groups is similar to that of the A and D subgenomes of cotton at the gross structural level. Applications of the map for the Australia wild C-genome species and cotton breeding are discussed. [ABSTRACT FROM AUTHOR]

Improving the quality of Australian cotton fiber is essential for maintaining industry viability. Two field experiments were conducted to assess the fiber quality and yarn performance of Australian bred cotton (five Gossypium hirsutum L. and one G. barbadense L.) genotypes. The work included the novel measurement of fiber maturity ratio, fiber linear density, and fiber diameter (ribbon width). The strongest yarns were produced using genotypes with the longest and finest fiber, for example, the strength of 20 tex yarns for the G. barbadense L. cultivar Sipima 280 (length = 36.6 mm, linear density = 143 mtex, ribbon width = 13.7 μm) was 25.4 cN tex-1 cf. the G. hirsutum L. cultivar Sicala 350B (length = 32.5 mm, linear density = 185 mtex, ribbon width = 14.5 μm) yarn strength of 18.1 cN tex-1. Micronaire was an inferior indicator of yarn performance, for example, the G. hirsutum L. breeding lines CHQX12B and CHQX377 each had micronaire values of 4.4, but CHQX377 spun stronger yarns due to its finer and more mature fiber. Lint cleaning had the greatest influence on nep (fiber knot) generation for G. hirsutum L. genotypes, generating on average 104 neps g-1 per lint cleaner passage. There was a negative association between fiber quality and yield, and a cost benefit analysis showed that fiber yield was the dominant economic factor compared to price premiums for better fiber quality. Alternative methods of determining fiber fineness will improve the value of Australian cotton. [ABSTRACT FROM AUTHOR]

The most common explanation for species diversity increasing towards the tropics is the corresponding increase in habitats (spatial heterogeneity). Consequently, a monoculture (like cotton in Australia) which is grown along a latitudinal gradient, should have the same degree of species diversity throughout its range. We tested to see if diversity in a dominant cotton community (spiders) changed with latitude, and if the community was structurally identical in different parts of Australia. We sampled seven sites extending over 20° of latitude. At each site we sampled 1–3 fields 3–5 times during the cotton growing season using pitfall traps and beatsheets, recording all the spiders collected to family. We found that spider communities in cotton are diverse, including a large range of foraging guilds, making them suitable for a conservation biological control programme. We also found that spider diversity increased from high to low latitudes, and the communities were different, even though the spiders were in the same monocultural habitat. Spider beatsheet communities around Australia were dominated by different families, and responded differently to seasonal changes, indicating that different pest groups would be targeted at different locations. These results show that diversity can increase from high to low latitudes, even if spatial heterogeneity is held constant, and that other factors external to the cotton crop are influencing spider species composition. Other models which may account for the latitudinal gradient, such as non-equilibrium regional processes, are discussed. [ABSTRACT FROM AUTHOR]

Abstract: Data on seasonal population abundance of Bemisia tabaci biotype B (silverleaf whitefly (SLW)) in Australian cotton fields collected over four consecutive growing seasons (2002/2003–2005/2006) were used to develop and validate a multiple-threshold-based management and sampling plan. Non-linear growth trajectories estimated from the field sampling data were used as benchmarks to classify adult SLW field populations into six density-based management zones with associated control recommendations in the context of peak flowering and open boll crop growth stages. Control options based on application of insect growth regulators (IGRs) are recommended for high-density populations (>2 adults/leaf) whereas conventional (non-IGR) products are recommended for the control of low to moderate population densities. A computerised re-sampling program was used to develop and test a binomial sampling plan. Binomial models with thresholds of T=1, 2 and 3 adults/leaf were tested using the field abundance data. A binomial plan based on a tally threshold of T=2 adults/leaf and a minimum sample of 20 leaves at nodes 3, 4 or 5 below the terminal is recommended as the most parsimonious and practical sampling protocol for Australian cotton fields. A decision support guide with management zone boundaries expressed as binomial counts and control options appropriate for various SLW density situations is presented. Appropriate use of chemical insecticides and tactics for successful field control of whiteflies are discussed. [Copyright &y& Elsevier]

Considerable amounts of phosphorus (P) fertilizer will be required on soils in the proposed Ord Stage II area of northwestern Australia if a sustainable dry-season, cotton-production system is to be established, because in their virgin state, the soils are known to be inherently low in P. This study aimed to determine P-fertilizer requirements on these soils to optimize cotton yield as well as nutrient uptake. Five rates of P fertilizer were applied to soil recently cleared of trees and prepared for irrigation. In the second year, these same rates were imposed over the trial. It was concluded that the application of 60 kg ha-1 of P was sufficient to allow maximum yield and quality for dry-season cotton grown in the first season on virgin soils in the Ord River Irrigation Area (ORIA), and a total of 80 kg ha-1 of P was required when cotton was grown over two seasons. [ABSTRACT FROM AUTHOR]

Helicoverpa armigera (Hubner) (Lepidoptera: Noctuidae) is an important lepidopteran pest of cotton (Gossypium spp.) in Australia and the Old World. From 2002, F2 screens were used to examine the frequency of resistance alleles in Australian populations of H. armigera to Bacillus thuringiensis (Bt) CrylAc and Cry2Ab, the two insecticidal proteins present in the transgenic cotton Bollgard II. At that time, Ingard (expressing CrylAc) cotton had been grown in Australia for seven seasons, and Boilgard H was about to be commercially released. The principal objective of our study was to determine whether sustained exposure caused an elevated frequency of alleles conferring resistance to CrylAc in a species with a track record of evolving resistance to conventional insecticides. No major alleles conferring resistance to CrylAc were found. The frequency of resistance alleles for CrylAc was <0.0003, with a 95% credibility interval between 0 and 0.0009. In contrast, alleles conferring resistance to Cry2Ab were found at a frequency of 0.0033 (0.0017,0.0055). The first isolation of this allele was found before the widespread deployment of Bollgard H. For both toxins the experiment-wise detection probability was 94.4%. Our results suggest that alleles conferring resistance to CrylAc are rare and that a relatively high baseline frequency of alleles conferring resistance to Cry2Ab existed before the introduction of Bt cotton containing this toxin. [ABSTRACT FROM AUTHOR]

A survey of cotton ( Gossypium hirsutum) volunteers was conducted along the 1400 km of a cottonseed transport route in north-east Australia to determine the extent of naturalisation from spilt seed. In each year, 1% of the road distance was inspected for volunteer plants. The survey results were juxtaposed with the eco-climatic suitability predictions from inferential modelling. Over 3 years, 22 cotton plants were found at eight sites. Within the cotton production region, volunteers averaged 2.28 plants km−1 of road; their most likely source was seed cotton spilt during the previous harvest. Further north, three plants were found over 3 years, at an average density of 0.089 plants km−1 of road; all three plants were found in locations with a positive Ecoclimatic Index. No secondary spread was detected. Roadside slashing reduced plant survival and the potential to produce seed. In the wet tropics, weed competition and slashing prevented volunteers establishing. The surveys indicate that roadsides in north-east Australia are a hostile environment for the establishment of cotton plants, with no evidence of naturalisation or secondary spread. Current transport practices utilizing fully covered loads present negligible risk of producing naturalised populations of cotton (either transgenic or non-transgenic) on roadsides in north-east Australia. [ABSTRACT FROM AUTHOR]

Much of the hemp plant is a carbohydrate known as cellulose, found mostly in the outer bark of the stem, which is about 75% cellulose, while the core is about half that or more. This is in fact typical of plants, making cellulose the most common compound in the vegetable kingdom. It is a simple compound, utilising the three common elements of carbon, hydrogen and oxygen, and is a structure of many glucose molecules compounded together. There are slight differences in the arrangement of the glucose from plant to plant, making for different qualities in the cellulose yielded. Hemp if one of the best plants for cellulose production for the reasons that the cellulose it produces is well suited for paper manufacture and textiles, and further, it grows quickly without any great need of pesticides. Hemp use has been suppressed in recent times, but due to its usefulness and the ecological advantages in harvesting hemp over cotton and trees, there has been a call for hemp use which is growing worldwide. Businesses such as Minawear in California and Ecofibres in Australia have been working for the last several years with hemp and both have seen an increase in demand. At present most hemp is grown in China, Canada and Eastern Europe, but has in history been grown in almost every country of the world, due to the ease with which it is cultivated and the need for the cellulose fibres that it yields. [ABSTRACT FROM PUBLISHER]

Little is known about the impact of sucking insects on cotton grown in tropical production areas. To examine this, an experiment was conducted at Katherine in northern Australia to determine the impact of mirids ( Creontiades dilutus (Stål) and Creontiades pacificus (Stål), green vegetable bug ( Nezara veridula (L.)) and red-banded shield bug ( Piezodorus hybneri (Gmelin)) on the yield and fibre quality of the transgenic cotton variety DP50bx containing genes for the expression of Cry1A(c) and Cry2A(b) δ-endotoxins of Bacillus thuringiensis Berliner variety kurstaki. The trial examined the impact of sucking insect populations in the range 0.5–2.0/m2. Yields of unsprayed plots were approximately 30% of those obtained in plots sprayed on a threshold of 0.5/m2 which did not differ significantly from plots sprayed regularly to exclude sucking insects. The increase in yield in the low pest density treatments was the result of improved fruit retention in the middle part of the plant. Fibre quality was similar in all treatments. However, damage ratings to individual bolls did differ between treatments. Bolls in the high insect density treatments received more damage than those in the low density treatments. As a result of this study, a tentative treatment threshold of 0.5 sucking insect/m2 is recommended in determinate Bollgard II cotton varieties grown in winter production areas. [ABSTRACT FROM AUTHOR]

Over the last 10 years, there has been a rapid expansion of rainfed cotton production in Australia. The majority of this area has used “skip row” configurations in which certain rows in the crop are not sown with the aim of providing a slowly available supply of soil moisture during periods of low rainfall. In the past, the OZCOT cotton crop simulation model has been used with long-term climate records to assess the impact of different management strategies for irrigated cotton production and to study the prospects for rainfed cotton production in the major cotton growing regions. In this paper, we present modifications made to OZCOT to better accommodate skip row. First, a simple procedure previously used to approximate light interception of row crops was assessed for its ability to enhance the capability of OZCOT to simulate skip row configurations and second, a modification to allow for the possibility that water in the skip is not as freely available as the water in the plant row was also explored. Including modifications to allow for differences in soil water extraction significantly improved predictions of crop yield for cotton in skip row configurations across a number of locations in the Eastern Australian cotton producing regions, but modifications to account for light interception in row configurations reduced the ability of the model to simulate skip row cotton yields. The modified model gave reasonable predictions of yield for solid planted and skip row crops. The performance was within the range of results published for solid planted crops over a range of nitrogen and irrigation treatments and planting dates. The model’s simulation of skip row yields when compared to solid planted crops grown under the same conditions, reflected the relationships seen in the measured data and those published in the industry literature. [Copyright &y& Elsevier]

Reports on the attempts of Australian crop scientists to improve the quality of natural cotton fibers by genetic engineering. Regulatory aspects of fiber development; Characteristics of genes expressed only in fiber cells.