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The changing global climate of more variable rainfall patterns and increasing temperatures is a severe threat to worldwide food security. There is need for adaptive technologies, agronomy, and crop varieties that will be capable of meeting and exceeding the projected demands of an increasing human population in the changing climate. An increase in average temperatures will result in crop cycles shortening and as such the vigour of varieties will need to increase to ensure optimum production occurs (Malhi et al. 2021). With up to ~20% of all calories consumed coming from wheat grain, it is therefore a vital component of food security and a focus for yield improvement (Erenstein et al. 2022). A proposed new wheat ideotype, of a highly early vigorous plant with a shortened lifecycle has been tested in Australian conditions, and has applicability on a global scale.
Australia is one of the largest wheat exporters, and is essential to worldwide food security. In the southern Australian wheatbelt, wheat is traditionally sown in the autumn to be grown over winter, flower in spring and then be harvested in early summer. With water availability the greatest limiter to yield, this allows for sufficient time for moisture to be harvested by the crop, and develop enough biomass before anthesis for conversion to grain yield (Richards et al. 2014). The timing of sowing in the autumn is crucial as it enables the plant’s phenological requirements of vernalisation, photoperiod, and earliness per se to be met over winter. This results in anthesis occurring in spring when the relative risks of frost and heat and drought stress are at their lowest. Mistimed flowering results in the sensitive floral parts being damaged, and a resultant drop in grain yield (Flohr et al. 2017). However, the timing of sowing in autumn, to ensure correct timing of anthesis, is often dictated by the colloquially termed autumn break. This is a flush of rainfall that growers will wait for until they sow. The autumn break provides good soil moisture, ensuring consistent and even germination of the crop. The changing climate has reduced the reliability of this rainfall and so many growers are being forced to sow into dry soil, and are encountering issues with poor germination, emergence, and crop stand establishment (Unkovich 2010). The proposed ideotype tested here negates the need for the autumn rainfall by delaying sowing into mid-winter into near guaranteed moisture. This delay in sowing requires the ideotype to have exceptionally high early vigour for biomass development, as well as hastened phenology to still time anthesis in the optimum flowering window in the spring (Chen et al. 2020). This paper covers a definition of the ideotype drawing upon global literature of short season, highly vigorous wheat varieties in addition to a multi-trait multi-environment analysis of short season wheats in Australian conditions.
References
Chen C, Wang B, Feng P, Xing H, Fletcher AL, Lawes RA (2020) The shifting influence of future water and temperature stress on the optimal flowering period for wheat in Western Australia. Science of The Total Environment 737, 139707.
Erenstein O, Jaleta M, Mottaleb KA, Sonder K, Donovan J, Braun H-J (2022) Global trends in wheat production, consumption and trade. In 'Wheat improvement: food security in a changing climate.' pp. 47-66. (Springer International Publishing Cham:
Flohr BM, Hunt JR, Kirkegaard JA, Evans JR (2017) Water and temperature stress define the optimal flowering period for wheat in South-Eastern Australia. Field Crops Research 209, 108-119.
Malhi GS, Kaur M, Kaushik P (2021) Impact of climate change on agriculture and its mitigation strategies: A review. Sustainability 13, 1318.
Richards R, Hunt J, Kirkegaard J, Passioura J (2014) Yield improvement and adaptation of wheat to water-limited environments in Australia—a case study. Crop and Pasture Science 65, 676-689.
Unkovich M (2010) 'A simple, self adjusting rule for identifying seasonal breaks for crop models, Proceedings of 15th Australian Agronomy Conference.'
| Keywords | Wheat; Short-season; Vigour; Australian: Ideotype |
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