Development of a rapid mass screening technique for the selection of cotton plant antibiotic resistance to Helicoverpa spp.

Abstract

ABSTRACT: When searchinq for an ideal mass screening technique for cotton plant antibiotic resistance to Helicoverpa spp., a 48 hour feeding on squares using final instar larvae bioassay was found to be the most suitable. It correlated better, than the techniques trialed, with the Standard larval bioassay traditionally used as an antibiotic resistance measurinq tool and was more energy efficient than the 'Standard'. An ideal mass screening technique usinq the two spotted mite (Tetranychus urticae} on cotton seedlings failed to correlate with the 'Standard1 rendering it unsuitable for measuring antibiotic resistance to Helicoverpa spp . ...The widely reported finding that gossypols are very important to the antibiotic activity against the cotton bollworm (Helicoverpa arnigera was supported with highly significant correlations between gossypol content of plant material and percent larval weight gains. In contrast, condensed tannin content of 'fresh plant' diet incurred insignificant antibiotic activity against the cotton bollworm but important antibiotic activity against the two spotted mite (Tetranychus urticae).

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Irrigated cotton strain and cultivar testing in Queensland

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The objective of this project was to evaluate preliminary and advanced breeding selections from the Narrabri and Biloela programs at up to five locations in Queensland. Over the period 1986/87 to 1988/89 this project played a vital role in selecting new cotton varieties for commercial production. Hundreds of lines from the Biloela and Narrabri breeding programs were evaluated in preliminary trials at Emerald, Biloela and Brookstead, while advanced material was tested in the Australian Cotton Cultivar Trials at these sites plus Theodore.

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Development of Improved Cotton Varieties

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This project is a long-running one concerned with breeding varieties adapted to Australian conditions, growing practices and markets. During the interval of this particular grant much progress occurred with the development of the original Siokras and Sicala's from a breeding program that began in 1974. The development of Siokra has been widely regarded as a noteworthy achievement since it marks the first time anywhere that an okia leaf variety has been successfully and widely grown commercially. The significance of the okra leaf has been that it has provided some tolerance to Heliothis and considerable tolerance to mites. Titls pest tolerance has resulted, where keen attention has been paid to pest management, in the savings of two or even more sprays. Very importantly both Siokra and Sicala had genes for bacterial blight resistance incorporated and had ready marketable fibre. These properties led to their readily acceptance by cotton farmers and they soon comprised between 65-75% of total Australian cotton plantings.

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Improved irrigation techniques for cotton production in the Macquarie Valley

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The overall aim of the soils research program based at Trangie has been to develop management strategies that maximise the profitability of irrigated cropping by: (i) correcting yield limiting soil physical problems; and (ii) by preventing further problemfrom developing. The work has been carried out on cracking clays and hard-setting red soil is with a strong emphasis on extension of the results to irrigation farmers. This project concentrated on evaluating the hydrological effects of deep ripping, chisel ploughing, mouldboard ploughing, minimum tillage, gypsum, and severa1 rotation crops on a furrow irrigated cracking clay. The subsequent effects upon cotton performance and farm economics were also measured and extended to cotton growers. Similar experiments were carried out on a hard-setting red soil.

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SIRATAC - An investigation of SIRATAC's Role in the Australian Cotton Industry

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Our objective was to undertake a collaborative research study to identify and investigate problems associated with the perceived "poor adoption rate of Siratac, and develop an action plan and advisory programme to significantly improve adoption

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Evaluation of Pix on Cotton

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Objective: Instigate research into application strategies for Pix on cotton in Australia and compare results with similar experiments from California. Of particular interest was the recent discovery that multiple applications of Pix gave superior yield results compared with a single application.

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NATO Advanced Research workshop on Mechanics and Related Processes in Structured Agricultural Soils, Univ. Minnesota, USA

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In the last year I requested funds for partial support towards a conference trip in the USA, together with a visit to the principal laboratory in the USA investigating tillage and compaction. After I made this application, I received a further invitation to undertake some work in West Germany with Professor Rainer Horn, a leading worker in the field of compaction. This work in West Germany was not supported by the Cotton Research Council, nor was it directly concerned with cotton soils. Nevertheless, the work that we undertook on compaction is of direct relevance to my work on the cotton soils, so I shall report on this visit also.

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