Soybean Genetics Newsletter


One of the major objectives of the proposal is systematic screening of all available soybean germplasm of Maturity Groups III to VIII for a natural resistance to a major insect pest, the Mexican bean beetle (MBB). These six Maturity Groups (III-VIII) cover abouL 5,000 plant introductions (Pis), 350 commercial varieties, and 80 breeding lines. Selected accessions of the most resistant (35% or less leaf defoliation) and highly susceptible (over 75% leaf defoliation) in general screening under field conditions were re-evaluated in triplicate in 1985 and in quadruplicate in 1986 (Table 2). About 20 special selections were evaluated for MBB under controlled environmental conditions.