Recurrent phenotypic selection and recurrent selection based on combining ability in tetraploid bahiagrass

Abstract

Paspalum notatum Flüggé is an apomictic grass used for forage and turf. The recent generation of a sexual synthetic tetraploid population of the species provides the uniqueadvantagetoexploitheterosisbyaccumulatingfavorableallelesthroughrecurrent selection cycles. The objective was to evaluate recurrent phenotypic selection (RPS) and recurrent selection based on combining ability (RSCA) as breeding methods. The best sexual genotypes in terms of warm-season growth from a sexual synthetic tetraploid population were selected by RPS and RSCA. The selected genotypes were polycrossed and two new sexual populations were created, which were crossed with superior apomictic genotypes. Both methods allowed obtaining families that were evaluated for summer, fall, and spring growth. Breeding values and heterosis were also calculated. Summer growth for RPS families was greater than for RSCA families (33.1 and 29.08 g plant−1, respectively); however, fall, spring, and accumulated growth were similar. The breeding value for RPS sexual parents was greater than for RSCA sexual parents for summer growth, whereas those for fall and spring growth were similar. A greater level of families with heterosis (80%) was observed for RPS than for RSCA (30%) for summer growth, whereas the levels for fallandspringgrowthweresimilar.Theseresultsindicatethatbothbreedingmethods were successful in improving tetraploid P. notatum. They increased the mean value of the progenies and produced families superior for forage yield by accumulating favorable alleles.