description
- This proposal centres on the exploitation of a wheat line generated at Nottingham containing a wild relative chromosome segment (introgression), that will enable the development of a robust hybrid wheat system. Hybrid varieties, proven to yield significantly more than inbred varieties, exhibit enhanced resilience to adverse climate conditions and disease resistance (BBRSC's current responsive mode spotlight) ensuring more predictable yields. Global food production faces a critical challenge due to rapid global population growth exacerbated by the negative effects of the changing environment. Over the next 50 years, the total grain production of wheat, a primary global food source and vital for the UK, must exceed that produced over the last 10,000 years since agriculture began, just to sustain current nutrition levels. In many in-breeding crops, a switch to hybrid breeding has substantially increased production, resilience, environmental sustainability, and quality of crops, e.g., 65% of maize production is now from hybrids. Hybrid seed production requires the inter-crossing of two genetically different genotypes: a female parent which is male-sterile, so that self-pollination is not possible, and a fertile male parent. The hybrid seed generated is more productive than both parents because of hybrid vigour and is harvested solely from the female parent to be sold directly to the farmer. A key requirement for hybrid production in in-breeding crops is the development of a system that enables the continuous production of female-fertile but male-sterile plants to be used as the female parent of the hybrid seed. While this has been achieved in crop species such as maize and rice, it has proved to be a major hindrance for hybrid production in wheat, a bottleneck this proposal seeks to address. This proposal outlines the development of such a system in wheat, exploiting a wheat-Aegilops mutica introgression line, carrying genes for restoring male fertility and blue grain colour. When crossed with the 'Probus' male-sterile ms1 deletion wheat line (used as the female parent of hybrid seeds), it confers a characteristic blue coloration to seed in the segregating progeny. The male-sterile female parent line is thus maintained by physically separating the seeds generated by colour sorting. However, for the system to function, a gene in the Ae. mutica introgression must be knocked out. This gene is of significant interest as it confers its own preferential transmission through both male and female gametes. The phenomenon of preferential transmission is widespread throughout wheat's wild relatives and has also been observed within wheat itself. However, the gene(s) responsible, its mode of action and evolutionary consequences still need to be determined. The proposed work will result in: 1) development of a robust system for hybrid wheat production, 2) identification of the gene(s) responsible for preferential transmission. The development of higher yielding, more resilient, hybrid wheat varieties that are adapted to the changing environment would transform global wheat production (aligns with essential components of BBSRC's Strategic Delivery Plan, Forward Look for UK Bioscience and the UK Plant Science Research Strategy). Furthermore, identifying the gene(s) responsible for preferential transmission will provide a springboard for understanding its mode of action and the impact it has had during the evolution of the Triticeae, allowing it to be used as an important tool for breeding wheat and other cereals.