Plant & Animal Genome V Conference
Town & Country Hotel, San Diego, CA, January 12-16, 1997.
PAG-V: W6 - IDENTIFICATION OF QTL FOR FLOODING TOLERANCE IN SOYBEAN
W6
IDENTIFICATION OF QTL FOR FLOODING TOLERANCE IN SOYBEAN
VANTOAI, TARA T
USDA-ARS, Soil Drainage Research, Columbus, OH 43210
Flooding adversely affects stand establishment, growth and productivity of soybean in many areas of the U.S. and the world. Tolerance to flooding can be divided into two types based on the mechanism involved: a) tolerance of seeds and seedlings to complete submergence and b) tolerance of established plants to soil waterlogging. Tolerance to flooding is a quantitative trait which, in other crops is controlled by a small number of genes. Quantitative trait loci and DNA markers for flooding tolerance were identified in soybean using the recombinant inbred population of Minsoy x Noir. The Minsoy x Noir map based >200 RI lines currently have >400 markers divided into ca 30 linkage groups. Eighty seven lines were screened for tolerance to complete submergence by drowning 3-day seedlings in degassed buffer for 18 h. At the end of the stress, the seedlings were allowed to grow for three days. Flooding tolerance was determined by scoring the seedlings for survival and for primary root growth. QTL on several linkage groups were identified at a level of significance <0.001. Primary root growth also was associated with QTL. Tolerance to soil waterlogging was screened with 130 lines under field and greenhouse conditions. At two weeks after planting, the soil was flooded to 2- 3 cm above the surface. Flooding continued for six weeks (8 weeks after planting) in the greenhouse or to the end of the season in the field. Flooding tolerance was determined by leaf color and plant height at six weeks of flooding and seed yield at the end of the season. QTL for these traits also have been determined. The correlation between greenhouse, potted plant and field assays will be discussed.