Plant Genome III Conference

MAJOR QTLs FOR POST-FLOWERING DROUGHT RESISTANCE IN GRAIN SORGHUM.

1. Department of Plant and Soil Sciences, Mail Stop 2122, Texas Tech University, Lubbock, TX 79409
2. Texas A&M University and TAES, Route 3, Box 219, Lubbock, TX 79401
3. Crop Biotechnology, Texas A&M University, College Station, TX 77843.

Drought resistance is a complex and important trait for the high and stable yield production in grain sorghum (Sorghum bicolr (L.) Moench). The objective of this study was to tag the stay green, a post-flowering drought resistance trait, in sorghum by using molecular markers. The F7 recombinant inbred line (RIL) population of B35 x Tx7000 was genotyped with RFLP makers and evaluated in the replicated field experiments in three locations of Texas for two years. Inbred lines B35 and Tx7000 show distinctly opposite responses to the drought at pre- and post-flowering stages. B35 is susceptible to preflowering drought and resistant to post- flowering drought. A molecular genetic linkage map presently with over 120 loci has been developed with the RILs. Three major regions have been found to control the stay green trait consistently in different environments. Results from a similar study with the F7 RIL-population of B35 x Tx430 will also be discussed to elucidate the effect of genetic background on tagging the stay green trait. (This project is supported by USDA-NRI Grant No. 9300872.)