Wednesday, November 15, 2006
274-9
Inheritance of Soybean Aphid Resistance in PI 567541B and PI 567598B.
Clarice Mensah, Chris DiFonzo, and Dechun Wang. Michigan State University, Dept. of Crop and Soil Science, East Lansing, MI 48824
Two soybean [Glycine max (L.) Merr.] plant introductions (PIs) were found possessing antibiotic resistance to the soybean aphid (Aphis glycines Matsumura) in early maturing germplasm in an earlier study. Plants with antibiotic resistance can negatively interfere with the reproduction of the aphid and can control the insect effectively. The objectives of this study were to determine the number of major genes that underlie the antibiotic resistance to soybean aphids. Information on the number of major genes controlling antibiotic resistance to soybean aphids is essential to design efficient breeding schemes to develop soybean varieties with antibiotic resistance to soybean aphids. All F1 plants from crosses between a susceptible and resistant cross were found to be susceptible to soybean aphids. Segregation data of aphid resistance in six F2 populations derived from susceptible x resistant crosses were collected in the field. The segregation data were tested for goodness of fit to a 15:1 (Susceptible: Resistant) ratio, which is the expected ratio for a trait controlled by two recessive genes. The observed ratios for the six populations did not deviate from the expected ratio.