description
- There is increasing global awareness of the importance of agriculture and food security. Predictions of a 50% population increase by 2050 emphasise the urgent need for sustainable, effective agricultural systems. Strategies for improved crop productivity without increasing environmental impact are critical. Selective breeding for key traits, combined with the use of hybrid lines has the potential to realise these goals. Hybrids are the progeny derived by crossing two distinct individual together. Hybrids tend to show "hybrid vigour", this can be seen in terms of increased growth, but also overall yield. Hybrid vigour results in the superiority of a hybrid over its parents, for example hybrid rice has 20-30% increased yield compared to inbreds as such hybrids are extremely valuable and in China hybrid rice constitutes >50% of all rice grown. However, the generation of hybrids is difficult and expensive, and has not been easy to achieve in temperate cereals, such as wheat and barley. Emasculation is often needed to generate hybrids, because plants frequently self-fertilise before cross-fertilising, this is labour intensive, requires specific germplasm, or has high environmental impact. The slow development of hybrid temperate cereals is a reflection of the bottleneck in the availability of germplasm and understanding of traits controlling male fertility. Recently there have been reports of Hystar hybrid wheat (Syngenta) with yield increases of ~0.5t/ha and hybrid barley (Syngenta) showing >10% increased yield. However, these reports are restricted by a lack of molecular understanding of cereal reproduction. There is also a need for subsequent rescue of male sterile lines, therefore approaches involving inducible gene systems, or switches in fertility based on environmental sensitivity are needed. It also seems likely that environmental changes, such as low/high temperature may be impacting on pollen viability and therefore reducing yield. A better molecular understanding of cereal pollen development that would facilitate effective control of male fertility would aid in increasing yield potential. Much of this knowledge of the molecular processes of pollen development has/is being developed in the model systems of Arabidopsis and Rice. This proposal will exploit this knowledge and utilise newly available techniques in wheat and barley genomic analysis to develop a Cereal Fertility Pipeline (CerFip) for trait transfer from model systems into temperate cereals for the control of male fertility. It will generate germplasm and genetic resources for the manipulation of fertility for selective breeding, maximal fertilization/seed set, and hybrid production, which are essential for yield improvement and food security. It will use comparisons between the different genomes to identify the corresponding genes in barley and wheat. These newly identified genes will be tested to confirm their role in pollen development and provide greater insight into male reproduction in temperate cereals. Germplasm will be developed to test selected genes for their application in switchable systems between male fertility and sterility. Such material will be potentially very valuable in the future development of systems to control fertility for hybrid development.