1a. Objectives (from AD-416)
The objective of this project is to develop an improved understanding of the physiological, molecular, and genetic basis of abiotic stress tolerance in sorghum in order to increase the productivity and nutritional quality of sorghum. Over the next 5 years we will focus on the following specific objectives: Objective 1: Develop and utilize new screening tools to identify and create novel sources of drought tolerance in sorghum. Objective 2: Identify quantitative trait loci (QTLs) contributing to abiotic stress tolerance and implement molecular marker-assisted selection for sorghum improvement. Specifically, germplasm collections will be mined for traits that will extend the growing season and enhance yield and biomass production. The genetic bases of cold and heat tolerance will be elucidated initially via genetic mapping of these traits from a new mapping population synthesized specifically for this purpose. Objective 3: Identify physiological traits associated with abiotic stress tolerance in superior germplasm and improved breeding materials. Objective 4: Enhance pre-flowering and post-flowering drought tolerance in sorghum by characterizing physiological drought stress responses throughout plant development, genetic mapping of these traits, identifying photoperiod-sensitive sorghum lines with post-flowering drought tolerance, and combining photo-period sensitivity and post-flowering drought tolerance in one sorghum genotype or line.
1b. Approach (from AD-416)
A comprehensive approach integrating Plant Physiology, Genetic Mapping, and Plant Breeding will be used to study the mechanisms of abiotic stress tolerance in sorghum and to develop superior germplasm with enhanced abiotic stress tolerance.
3. Progress Report
A method to screen for the post-flowering drought tolerance (staygreen) trait was tested in the field on known pre- and post-flowering drought-tolerant lines, and the method has been published. New genetic sources of pre- and post-flowering drought tolerance were identified from the Sudan sorghum germplasm collection. These new drought-tolerant lines will be confirmed in the field in the growing season of 2010. Milestone 4, sub-objective 2B was suspended due to loss of a sorghum breeder; all the milestones are fully or substantially met.
Lu, C., Xin, Z., Ren, Z., Miquel, M., Browse, J. 2009. An enzyme regulating triacylglycerol composition is encoded by the ROD1 gene of Arabidopsis. Proceedings of the National Academy of Sciences. 106(44):18837-18842.