Size optimization of a cantilever beam under deformation-dependent loads with application to wheat stalks

In this paper, we consider the optimization of the cross-section profile of a cantilever beam under deformation-dependent loads. Such loads are encountered in plants and trees, cereal crop plants such as wheat and corn in particular. The wind loads acting on the grain-bearing spike of a wheat stalk vary with the orientation of the spike as the stalk bends; this bending and the ensuing change in orientation depend on the deformation of the plant under the same load.The uprooting of the wheat stalks under wind loads is an unresolved problem in genetically modified dwarf wheat stalks. Although it was thought that the dwarf varieties would acquire increased resistance to uprooting, it was found that the dwarf wheat plants selectively decreased the Young's modulus in order to be compliant. The motivation of this study is to investigate why wheat plants prefer compliant stems. We analyze this by seeking an optimal shape of the wheat plant's stem, which is modeled as a cantilever beam, by taking the large deflection of the stem into account with the help of co-rotational finite element beam modeling. The criteria considered here include minimum moment at the fixed ground support, adequate stiffness and strength, and the volume of material. The result reported here is an example of flexibility, rather than stiffness, leading to increased strength.

Pre-emptive Breeding for Russian Wheat Aphid Resistance

The aims of the project are to 1) identify closely linked molecular markers to resistance genes and validate them in Australian wheat and barley backgrounds, and 2) introgress RWA resistance into Australian wheat and barley backgrounds.

Development of pedigree mapping for wheat

The aim of this project is to build on the work done so far in applying pedigree mapping principals to northern adapted wheat pedigreed to identify robust QTL for quality traits.

Stay-green wheat for increased yield and yield stability

This project will provide information, germplasm, selection techniques and strategies for breeders to develop high-yielding stay-green wheat cultivars for Australian growers via a "three pronged" research strategy.

DAQ566 Genetic approaches to resist to Fusarium and Bipolaris in wheat/barley

Genetic approaches to resistance of bread wheat to crown rot and common root rot.

Improving management of summer weeds in dryland cropping systems with Cotton

In 2001 a scoping study (phase I) was commissioned to determine and prioritise the weed issues of cropping systems with dryland cotton. The main findings were that the weed flora was diverse, cropping systems complex, and weeds had a major financial and economical impact. Phase II 'Best weed management strategies for dryland cropping systems with cotton' focused on improved management of the key weeds, bladder ketmia, sowthistle, fleabane, barnyard grass and liverseed grass.In Phase III 'Improving management of summer weeds in dryland cropping systems with cotton', more information on the seed-bank dynamics of key weeds was gained in six pot and field studies. The studies found that these characteristics differed between species, and even climate in the case of bladder ketmia. Species such as sowthistle, fleabane and barnyard grass emerged predominately from the surface soil. Sweet summer grass was also in this category but also had a significant proportion emerging from 5 cm depth. Bladder ketmia in central Queensland emerged mainly from the top 2 cm, whereas in southern Queensland it emerged mainly from 5 cm. Liverseed grass had its highest emergence from 5 cm below the surface. In all cases the persistence of seed increased with increasing soil depth. Fleabane was also found to be sensitive to soil type with no seedlings emerging in the self-mulching black vertisol soil. A strategic tillage trial showed that burial of fleabane seed, using a disc or chisel plough, to a depth of greater than 2 cm can significantly reduce subsequent fleabane emergence. In contrast, tillage increased barnyard grass emergence and tended to decrease persistence. This research showed that weed management plans can not be blanketed across all weed species, rather they need to be targeted for each main weed species.This project has also resulted in an increased knowledge of how to manage fleabane from the eight experiments; one in wheat, two in sorghum, one in cotton and three in fallow on double knock. For summer crops, the best option is to apply a highly effective fallow treatment prior to sowing the crops. For winter crops, the strategy is the integration of competitive crops, residual herbicide followed by a knockdown to control survivors. This project explored further the usefulness of the double knock tactic for weed control and preventing seed set. Two field and one pot experiments have shown that this tactic was highly effective for fleabane control. Paraquat products provided good control when followed by glyphosate. When 2, 4-D was added in a tank mix with glyphosate and followed by paraquat products, 99-100% control was achieved in all cases. The ideal follow-up times for paraquat products after glyphosate were 5-7 days. The preferred follow-up times for 2, 4-D after glyphosate were on the same day and one day later. The pot trial, which compared a population from a cropping field with previous glyphosate exposure and a population from a non-cropping area with no previous glyphosate herbicide exposure, showed that the pervious herbicide exposure affected the response of fleabane to herbicidal control measures. The web-based brochure on managing fleabane has been updated.Knowledge on management of summer grasses and safe use of residual herbicides was derived from eight field and pot experiments. Residual grass and broadleaf weed control was excellent with atrazine pre-plant and at-planting treatments, provided rain was received within a short interval after application. Highly effective fallow treatments (cultivation and double knock), not only gave excellent grass control in the fallow, also gave very good control in the following cotton. In the five re-cropping experiments, there were no adverse impacts on cotton from atrazine, metolachlor, metsulfuron and chlorsulfuron residues following use in previous sorghum, wheat and fallows. However, imazapic residues did reduce cotton growth.The development of strategies to reduce the heavy reliance on glyphosate in our cropping systems, and therefore minimise the risk of glyphosate resistance development, was a key factor in the research undertaken. This work included identifying suitable tactics for summer grass control, such as double knock with glyphosate followed by paraquat and tillage. Research on fleabane also concentrated on minimising emergence through tillage, and applying the double knock tactic. Our studies have shown that these strategies can be used to prevent seed set with the goal of driving down the seed bank. Utilisation of the strategies will also reduce the reliance on glyphosate, and therefore reduce the risk of glyphosate resistance developing in our cropping systems.Information from this research, including ecological and management data were collected from an additional eight paddock monitoring sites, was also incorporated into the Weeds CRC seed bank model "Weed Seed Wizard", which will be able to predict the impact of different management options on weed populations in cotton and grain farming systems. Extensive communication activities were undertaken throughout this project to ensure adoption of the new strategies for improved weed management and reduced risk for glyphosate resistance.

DAQ00141 Recurrent Selection Program in Hexaploid Wheat

Joint project with the University of Queensland that will use the recurrent selection breeding method to produce adapted, high-yielding and disease resistant wheat parents to breeders.

Herbicide tolerance of barley and wheat cultivars in NR (phase III)

During the past 10 years, this project tested 23 barley and 51 wheat varieties with 19 and 34 registered herbicides, respectively. It concentrated on new varieties and herbicides. The research highlighted that Northern Region (NR) wheat and barley varieties differed considerably in their sensitivity to these herbicides. Overall, 9 per cent of wheat variety x herbicide combinations and 6 per cent of barley variety x herbicide combinations had significant yield losses (3 to 38%) from herbicides at recommended rates and crop stages. In addition, 21 to 23 per cent had significant yield losses from herbicides at double rates, indicating a narrow margin of crop safety.

Transition of EGA wheat breeding activities to Australian Grain Technologies

Transition of EGA wheat breeding activities to Australian Grain Technologies.

Genetic approaches to resistance to Fusarium and Bipolaris in wheat and barley

This project provided information on the genetics of crown rot (CR) resistance to help breeding work, located new parent lines in wheat and barley, and provided an insight into yield losses that occur in commercial varieties with increasing levels of CR for risk management. Genetic experiments found some highly resistant lines were poor parents, and CR resistance was complex. Best parent lines and many specific crosses were identified for further work. New potential parent lines were identified in wheat and barley, some now used in breeding programs. Yield loss can be severe even with low levels of CR when combined with drought stress. CR can reduce yield even with a wet finish.

SIP04 Defect Elimination Wheat

Defect elimination in wheat. Black point in bread wheat.

DAQ00096 - Emerging Foliar Wheat Disease Issues in the Northern Region

The emerging disease program seeks to gain information on the distribution of cereal pathogens\pathotypes and potential for outbreaks across the norther region and options for their control. It is looking for an improved understanding of varietal (APR) reaction to stripe rust (YR) in prevailing weather conditions and in the face of climate change. Replicated field trials are used in the evaluation of varietal, cultural and chemical management of YR. Best management practice packages are disseminated to stake holders, including a YR predictive tool.

Cropping options to limit root-lesion nematodes

Australia’s northern grain-producing region is unique in that the root-lesion nematode (RLN), Pratylenchus thornei predominates. P. neglectus is also present. RLN cause substantial yield losses, particularly in wheat, but they reproduce on numerous summer and winter crops. Each nematode species prefers different crops and varieties. This project provides growers with a range of integrated management strategies to limit RLN (i.e. identify the problem, protect uninfested fields, rotate with resistant crops to keep populations low and choose tolerant crops to maximise yields). It also provides new information about soil-borne zoosporic fungi in the region.

DAQ00104 Sponge and dough bread quality of Australian wheat germplasm

The main grade of wheat targeted for the export sponge and dough (S&D) market is Australian prime hard (APH). By association, protein should be a key parameter relating to S&D quality, specifically loaf volume (LV). Surprisingly, the project revealed a low level of correlation between total protein content and LV. It appears that protein composition may be the key to understanding S&D quality, as the glutenin Glu D1 5+10 subunit contributed to the highest LVs. The current varieties KennedyA and SunzellA, together with several breeding lines, provided a consistently high quality over a number of seasons. These varieties performed as well as, if not better than, North American S&D varieties.

Using wheat flour in the production of organic banana prawns

Banana prawn (Fenneropenaeus merguiensis) juveniles (1-2 g) were compared for survival, growth and condition after feeding in tanks over one month with several simple diets based on organically certified whole wheat flour. All feeds were applied once per day at 6% of the starting body weight, and produced high survival (>94%). A commercial Australian prawn feed used as the control diet produced the highest (P<0.05) growth (101% weight gain) and condition measured as the length of antennae (13.2 cm). The unfed control had significantly (P<0.05) lower survival (56%), and resulted in a weight loss (3.1%) and the shortest antennae (9.4 cm). Adding free flour to tanks produced lower (P<0.05) growth (6.9%) and shorter (P<0.05) antennae (10.3 cm) than adding pelletised flour with low levels (dry weight) of additional nutritional substances and feed attractants (chicken’s whole egg: 1.5%, polychaete slurry: 1.1% and 6.8%, molasses: 4.2%). Rolling the flour into a dough ball also appeared to marginally improve its direct utilisation by the prawns. These results are considered within the context of appropriate nutrition for Penaeids and successfully producing certified organic prawns in Australia.