Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 3/3/2007
Publication Date: 3/5/2007
Citation: Burow, G.B., Franks, C.D., Xin, Z. 2007. Genetic and Physiological Analysis of an Irradiated Bloomless Mutant (Epicuticular Wax Mutant) of Sorghum[abstract]. Southern Section of the American Society of Plant Biology. Mobile, Alabama. March 3-5, 2007.
Technical Abstract: Sorghum (Sorghum bicolor (L).Moench.) is one of the most drought tolerant and water efficient grass species. A distinctive feature of sorghum is the profuse deposition of epicuticular wax or bloom on the abaxial side of the leaf and sheaths which has been proposed as one of the possible trait contributing to the species’ over all abiotic stress tolerance. However, the role and contribution of epicuticular wax to drought tolerance has been inconclusive. In this study, we characterized a bloomless mutant, (KFS2021 developed via gamma irradiation) using a combination of genetic and physiological approaches and provided evidence for the contribution of epicuticular wax in reducing night transpiration. Phenotypic segregation for the bloomless trait in an F2 population developed from a cross between KFS 2021 and BTx623, suggest that in this cross, the bloomless phenotype is a result of mutation in a single nuclear recessive gene. The bloomless parent and F2 progenies had lower frequency of guttation, more leaky cuticular layer (measured based on chlorophyll leaching in 80% ethanol) and higher rate of seedling water loss than the wild type and bloom progenies. More important, bloomless progenies consistently showed 3 to 6- fold higher night time transpiration based on measurement of night time conductance. Genetic correlation analysis of traits showed significant associations which indicate the important role of epicuticular wax in the various physiological traits analyzed in this study. Taken together these results suggest that sorghum epicuticular wax or bloom may enhance water use efficiency by depressing night time water loss.