Inheritance of Resistance to Whitefly Bemisia Tabaci (Gennadius) in Soybean.

Whitefly Bemisia tabaci (Gennadius) is a common economic pest in a great number of crops throughout the world. In soybean, they can be vectors of viruses, e.g. soybean crinkle mosaic and soybean dwarf mosaic. Resistance to whitefly has been identified in soybean, however, whitefly resistance genes have not been identified. The objectives of the study were: 1) to screen germplasm to identify soybean resistance and susceptible accessions, 2) to determine the inheritance of resistance to whitefly in soybean, and 3) to locate the resistance locus (or loci) to a linkage group (or groups) using simple sequence repeat (SSR) markers. Ten lines were screened for whitefly resistance. An F2:4 population derived from the cross between the selected whitefly resistant line ‘Cajeme' and the susceptible line ‘Williams 79' was developed to determine the inheritance of resistance to whitefly. Parental lines were screened with 120 SSR of which 90 polymorphic markers were selected to screen the lines in the F2 population. In 2003 and 2004, F2:4 populations and parents were evaluated for whitefly infestation in a complete randomized design at one location in Mexico. This location was selected because whitefly is a common pest of soybean in this country. Marker data were analyzed for linkage and combined with phenotypic data to identify QTL. The range of continuous variation in whitefly infestation observed in the F2:4 segregating population indicates evidence of polygenic inheritance of whitefly resistance.