ALTERNATIVE DWARFING GENES FOR IMPROVING EMERGENCE AND WATER USE EFFICIENCY IN WHEAT UNDER DROUGHT Abstract uri icon

abstract

  • The projected global and India’s wheat demand is 1090 and 140mt by 2050 respectively. This target can be achieved with annual production growth of 1.7 percent. There is ceiling in wheat yield under high productive areas, hence the other potential source to increase yield is stressed environment. Worldwide 84mha of wheat growing area is affected by drought and traditional breeding efforts focused on yield rather than survival, this present a challenge to wheat scientists to develop wheat cultivars that are both productive and adapted to abiotic stress. Recently physiological traits (PTs) have become a target for plant breeders aiming to improve yield potential in stressed environment. Currently >70% of modern semi-dwarf wheat cultivars possess major GA3-insensitive Rht1 and Rht2 dwarfing genes to increase the grain yield. But these dwarfing genes have negative effect during deeper sowing as along with reducing plant height it also reduces coleoptile length. But GA sensitive or alternative dwarfing Rhts like Rht 4,5,8, and 13 have advantages as they do not have negative effect for emergence from deeper soil layer but they do reduce the plant height. A set of 62 wheat lines with different GA sensitive Rhts along with their commercial checks were received from CSIRO Australia to India under Indo Australian collaborative project. The presence of designated Rhts in these imported lines were confirmed by using molecular markers and also by external application of GA. They were validated for their emergence both at 10 and at 15cm depth of sowing and also at early and timely sowing conditions at three different drought stress areas of India namely at Karnal, Indore and Pune for two years. The phenotypic data necessary for evaluation at seedling stage and pre & post-harvest data were also recorded along with coleoptile length and plant height. The emergence data showed that genotypes with GA sensitive Rhts had good establishment both at 10 and at 15cm depth of sowing compared to Rht 1 and 2. The best lines with good emergence were identified for different study locations and also for across the locations. The identified lines were extensively used in rainfed wheat breeding programme of India and four lines developed are under national coordinated yield trial for rainfed condition in India. Hence, this study provided an opportunity to introgress new GA3 sensitive genes in Indian cultivars for improving drought tolerance and water use efficiency in wheat.

publication date

  • July 2019