Comparison of Half-Sib and S1 Recurrent Selection in the Krug Yellow Dent Maize Populations1
- A. H. Tanner and
- O. S. Smith2
Eight cycles of half-sib family [BSK(HI)] and St progeny [BSK(S)I recurrent selection have been completed in cv. Krug Hi I Syn.3 (BSK), a strain of the open-pollinated maize (Zea mays L.) cv. Krug Yellow Dent. Experiments were conducted to evaluate and compare the changes in grain yield, grain moisture, and lodging in BSK(S), BSK(HI), and in crosses with testers used in the BSK(HI) program. The genetic gains per cycle for grain yield in the populations per se for Cycles 0 to 4, adjusted for the effects of finite population size, were significantly larger for BSK(S) than for the BSK(HI). Cycles 4 to 8, genetic gains (adjusted for drift) in BSK(S) were lower (not significantly) and higher for BSK(HI), compared with their respective rates in Cycles 0 to 4. This resulted in a nonsignificant difference between methods for Cycles 4 to 8. In the populations selfed and in crosses with testers used in the BSK(HI) program (averaged over three testers), genetic gains paralleled gains in the populations per se, except for Cycles 4 to 8 in BSK(HI). The effects of finite population size (genetic drift) were significant for grain yield for both methods and confounded the observed response to selection, especially in Cycles 4 to 8. The effects of drift were larger in BSK(S). Genetic gains, adjusted for drift, were smaller than predicted gains for both methods.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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