Plant Genome III Conference

QTL ANALYSES OF YIELD AND RELATED DROUGHT RESISTANCE TRAITS IN GRAIN SORGHUM

1. Dept. of Plant and Soil Sciences, Box 42122, Texas Tech University, Lubbock, TX 79409
2. Texas A&Z University and TAES., Route 3, Box 219, Lubbock TX 79401
3. Crop Biotechnology Center, Texas A&M University, College Station, TX 77843.

Drought resistance has been a prime breeding objective in sorghum (sorghum biclor L.) improvement programs. However, the progress in this direction has been slow because of the complexity of the drought responses. The objective of this research is to identify DNA markers that are linked to yield and related drought resistance traits. The two genotypes, B35 and Tx430, and 98 of their F7 recombinant inbred lines (RILS) were planted under limited-irrigation (post-flowering drought stress) and rainfed (pre-flowering drought stress) conditions in two locations during 1993 and 1994. Fully irrigated (control) experiments were also maintained in two locations during 1994. Grain yield and its components, and other related drought resistance traits were recorded. More than 100 RFLP markers have been mapped using the RIL population. The results of the SAS and QM analyses involving traits such as the resistance to reduction in yield and its components in response to drought stress will be presented. The effect of genetic background on tagging these drought resistance traits will also be discussed using results of a similar study with the F7 RIL-population of B35 x Tlx7OOO. (This project is supported by USDA-NRI Grant No. 9300872.)