For the synthetics, grain of 137 Sa ears for SZA and 132 for SZB was evaluated for weevil resistance in the CTH laboratory at CIMMYT's research station at Harare, Zimbabwe.
The best 14 lines (10% of 137 lines) and the worst 14 lines were selected for SZA; and the best and worst 13 lines (10% of 132 lines) were selected for population SZB.
1] lines was being assayed for weevil resistance (above), remnant seed of all the 137 lines for SZA and the 132 for SZB was planted and the lines were advanced to [S.
At the same time, all six synthetics from SZA were crossed to their corresponding heterotically complementary synthetics in SZB to form six crosses, plus their reciprocal crosses.
Weevil resistance parameters for synthetics made from biparental populations were analyzed separately from those for SZA and SZB.
Means were computed for weevil resistance parameters for all synthetics formed by divergent selection for SZA, SZB, and the four biparental populations.
Differences for weevil resistance among synthetics were generally independent of source population, except that synthetics from SZB had somewhat longer MDP (suggesting greater weevil resistance) than those from SZA (Table 3).
2] selection succeeded to significantly improve weevil resistance and divergently separate the two populations, SZA and SZB (Table 5).
Divergent selection results from the four biparental populations and for SZA and SZB are summarized in Table 5.
Address correspondence to Sharon Vaughn, The University of Texas at Austin, College of Education, One University Station, SZB
D4900, Austin, TX 78712-0365 (e-mail: SRVaughnUM @aol.
Correspondence concerning this article should be addressed to Sharon Vaughn, The University of Texas at Austin, Texas Center for Reading and Language Arts, SZB
228, Austin, TX 78712 E-mail: SRVaughnUM@aol.