Reciprocal Full‐Sib Selection in Maize 1

Reciprocal full‐sib selection was initiated in BS10 and BS11 maize ( Zea mays L.) populations to emphasize selection for specific combining ability. Grain yield was the primary trait under selection, but consideration also was given to maturity and lodging resistance. Selection was based on performance of full‐sib progenies, and S 1 progenies of the parents of the superior full‐sib progenies were intermated to synthesize the next cycle population. The original populations and their population cross, and the most advanced cycle populations and their crosses, also were included in most evaluation trials to provide information on relative response to selection. The primary objective of this paper is to summarize results of seven cycles of reciprocal full‐sib selection in BS10 and BS11. Direct response in the population cross was 2.1% per cycle for yield. Correlated response in BS10 and BS11 was 2.7 and 2.4%, respectively. Gradual improvement was realized in BS10 and the population cross, but most of the improvement in BS11 was made in the first cycle of selection. Relative to the mean of the six check hybrids included in all trials, the mean yield of the full‐sib progenies increased six standard deviations. There was no evidence that the variability among full‐sib progenies had decreased with seven cycles of reciprocal full‐sib selection. Evidence suggested that maturity was not later in advanced cycles and that stalk quality was improved. Percentage of root lodging and dropped ears did not show any trend with selection. Direct and correlated responses of reciprocal full‐sib selection in BS10 and BS11 were similar to those reported for other recurrent selection methods in other populations. Reciprocal full‐sib selection is somewhat more complex than other methods of recurrent selection, but it seems useful in certain situations where desired to select for general and specific combining ability.