The sensitivity of genetic fingerprinting rests in the ability of the procedure to detect the rare or subtle differences that exist between the genes of one individual and another. In a typical experiment, discrete subsets of the genetic material (DNA) of two or more organisms are analysed for genetic similarities and differences, and calculations are made as to the likely relatedness of the organisms based on the observed genetic similarity. In the present investigation, we have applied the RAPD-PCR technique 1 to strains of V. dahliae isolated from cotton plants from a range of production regions in Australia. By using genetic fingerprinting to identify different strains of V. dahliae, we hope to achieve a better understanding of the epidemiology of Verticillium wilt disease in cotton.

A three-year project to obtain baseline data describing the average soil condition in the lower Macintyre, Gwydir and Namoi valleys. A priority for this study is to establish a store of soil information (of known precision) that can be used in land management planning and environmental modelling. The focus of this paper is on distributionpatterns of soil salinity in the Macintyre portion of the study.

While among researchers simulation models are consider to be useful tools, modelling has a badreputation in the industry. Many people feel it has very little connection with what happens in the field. Part of the problem is a misunderstanding of how models are developed and what sort of information we can expect to get from them. In this paper I will consider some of the steps we go through in building a model and what we can do with them. I will also give an outline of the CERCOT model currently under development at the Australian Cotton Research Institute.

In cotton, the best known of the secondary metabolites isolated, Gossypol, have been found to have antifungal and antitumour activity (Harborne and Baxter, 1993) and to target enzymes in the signal transduction system, notably protein kinase A and myosin light chain kinase (Jinsart, 1991, 1992) . This project aims to define the chemical structure, high affinity biochemical sites of action and biological activities (especially anti-insect and antifungal activities) of cotton defensive proteins and secondary metabolites.

Nutgrass (Cyperus rotundus) remains one of the major problem weeds of cotton production. However, extensive research has show nutgrass can be controlled using management strategies which: ensure a strong, competitive crop; use herbicides to control nutgrass when its actively growing; use cultivation when nutgrass is stressed, in hot, dry conditions, and; prevent nutgrass spreading on equipment. Results from last season were very promising, with even a single, shielded Roundup application dramatically reducing the nutgrass population. Two growerswho applied glyphosate in-crop last season, were extremely pleased with their results. Research plots in one fieldfield showed a 0.8 bales/acre yield increase when shielded Roundup was applied in-crop on 3 occasions.

The computer based decision support system, entomoLOGIC was first developed five years ago as a basic prototype. The first release of the DOS version for commercial use was at the Cotton Conference in 1992. This program was developed and improved over the next 3 years and has been widely used by cotton growers and agronomists. Following much feedback from users, entomoLOGIC was completely rewritten in a Windows environment and released as entomoLOGIC 95 for the 1995/96 season. entomoLOGIC 95 was easier to use and also more capable than the DOS version. As well as insect management technology, it incorporates a field and crop history system which allows growers to record all production activities

Although growers spend much of their time and resources in protecting their cotton crop against attack by insect pests and diseases the plant itself is already well armed against these invaders and your task might be hopeless if not for the complex array of natural chemicals produced by the plant. Of particular note are the terpenoid aldehydes, such as gossypol, found in the oil rich gossypol glands all over the plant. These glands are characteristic of cotton and its wild relatives and are full of an oil that is rich in different terpenoid chemicals. When an insect eats some of a leaf these glands burst and release a toxic array of chemicals, some of which have been shown to have a high potency against insects. Besides this constitutive defence against herbivory, the plants also have an inducible defence mechanism that can detect and respond to disease pathogens with the production of more terpenoids and other antifungal chemicals as a first line of defence to limit their invasive capacity.

The introduction of Bt-transgenic cotton (Ingard) should lead to an overall reduction in insecticide use. increased survival of predators should follow, which will help to reduce outbreaks of secondary pests, such as spider mites and aphids. Paradoxically, reduced pesticide use may increase problems with minds and their control with broad-spectrum insecticides could reduce beneficial numbers and increase secondary pest outbreaks. Synthetic insecticides will remain a key component of cotton production for the foreseeable future and this also has implications for secondary pests in Bt-cotton. These and other possibilities for the transgenic era are discussed below. What actually occurs will depend on many factors, such as the price of transgenic technology, cotton prices, rainfall, refuge requirements, insecticide resistance and so on. Crystal ball gazing is a risky business - in 10 years' time my thoughts will appear either prophetic or pathetic. Nevertheless, I have tried to analyse the likely pest status of secondary pests in the transgenic era and to indicate some of the measures that could reduce or deal with potential problems now and in the future.

The CSIRO Cotton Cultivar Trial (CCT has been run cooperativeIy by CSIRO and DPIQ for 22 years and is used as the last stage in our breeding fine evaluation. Early generation testing following single plant selection involves unreplicated progeny rows at the Australian Cotton Research institute, further progeny row tests and multiple row replicated trials at a haired number of farm sites. At each stage, lines with poor seedling vigour, disease susceptability, poor fibre quality or low yield are removed from further testing. The CCT involves 13 irrigated sites and three dryland sites in all major cotton growing regions in Australia from Central Queensland (Emerald, Bitoela and Theodore), manstteam western areas (Bourke, Collarenebri and St. George), mainstream eastern areas Ovarren, Merail North, Myall Vate, Moree, Boggabilla and Dalby) and cool season areas Breeza and Brookstead).

Summary Following square and boll loss, damaged plants may became taller and leafier than undamaged plants. Due to these changes, damaged plants may be better able to compete with their neighbours for light, water and nutrients. This explains why undamaged plants with damaged neighbours yielded about 50% less than undamaged plants with undamaged neighbours in field experiments at Narrabri. Yield reductions due to fruit loss could be greater than expected because of the negative influence of damaged plants on undamaged neighbours.