Agriculture, Food and Wine publications

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Browsing Agriculture, Food and Wine publications by Author "18th Australian Agronomy Conference (24 Sep 2017 - 28 Sep 2017 : Ballarat, Victoria)"

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    Differences in yield physiology in wheat cultivars grown under frost-prone field conditions in Southern Australia
    (Australian Society of Agronomy, 2017) Ferrante, A.; Zerner, M.; Leske, B.; Biddulph, B.; March, T.; 18th Australian Agronomy Conference (24 Sep 2017 - 28 Sep 2017 : Ballarat, Victoria)
    Low temperatures during the flowering period of cereals can lead to floret sterility and subsequent yield reduction. In this study we aimed to understand the physiological bases of yield determination among wheat genotypes grown under frost conditions in southern Australia. One experiment was carried out at Mintaro in South Australia in 2016. Treatments consisted of five wheat cultivars and a synthetic-derived wheat line sown at two different times of sowing (TOS) under field conditions. Yield and yield components were analysed at maturity. To analyse in more detail changes in grain number m-2 in response to frost, we mapped the distribution of grains within the spike. The trial experienced early frosts that mostly affected TOS 1, as a result the grain yield of TOS 2 was 3-fold higher than TOS 1. Sterility varied depending on TOS, cultivars and their interactions. For example, the later maturing variety ‘Yitpi’, which in part avoided the early frost, had the lowest level of sterility in contrast to the earlier maturing varieties such as ‘Scout’, ‘Wyalkatchem’ and ‘Mace’ which showed up to 100% sterility in TOS 1. In addition, we showed a clear trend to increase the number of spikelets exhibiting a significant difference in fertility between TOS. Therefore, optimising flowering time to minimise frost exposure is amongst the most important strategies to minimise frost damage while managing heat and drought stress.
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    The effects of wheat seed quality are greatest in high yielding environments
    (Australian Society of Agronomy, 2017) McDonald, G.; Hussein, S.; 18th Australian Agronomy Conference (24 Sep 2017 - 28 Sep 2017 : Ballarat, Victoria); O'Leary, G.; Armstrong, R.; Hafner, L.
    The size and composition of seed varies considerable between sites and seasons and it is often suggested that plump seed with a high nutrient concentration will benefit yield. There have been few field experiments that have examined this idea critically. Experiments were conducted over three years at low and medium rainfall sites in South Australia to examine the relative effects of seed source and seed size on yield. Grain was selected from National Variety Trials (NVT )sites based on differences in seed nutrient concentrations and graded into two or three size categories. Grain nutrient concentrations varied considerably between sites and grading the seed did not influence seed nutrient concentrations. Seed source influenced yield in only two of the eight experiments and the effects of seed source varied with variety. The effect on yield varied from about 4% up to 28%. Seed P concentration was the nutrient most commonly associated with yield variation. Using large seed improved crop establishment and crop vigour but yield benefits of large seed were only achieved at higher yielding sites where the benefit was about 5%. There was no improvement in yield. In one instance there was a yield penalty from sowing large seed where yields were lower than 2 – 2.5 t/ha. The results suggest that seed size has a smaller, but more consistent effect on yield compared to seed source, and the effects of seed source varied with variety. The benefits from improved seed quality were only achieved at sites where yields were higher than approximately 3 t/ha.