Combining ability and multiple parent‐based approach to derive simultaneous transgressive segregants for multiple traits in cotton (Gossypium hirsutum L.)

Abstract

Plant breeders are always in pursuit of desirable genes and gene complexes, leading to identification of potential and promising individuals/segregants often exhibiting traits with higher intensity. Identifying segregants with desirable combination of multiple traits would enable a breeder to develop superior cultivars. In this study, combining ability and multiple parent‐based approach was employed to derive segregants simultaneously superior for multiple traits. Single and double crosses were developed by crossing 11 parental lines in half diallel fashion and were evaluated under seven environments. To create crosses, the parental lines with the highest positive gca effects were selected in addition to desirable yield and fibre quality traits (SCYP, NOBP, BW, GOT, UHML and FS). The positive and significantly higher gca effects in these parents is an evidence of prominence of additive and additive × additive component of genetic variance. To identify desirable segregants, six F2 populations derived from four single and their two double crosses were evaluated by raising an optimal population size of 910–935 and 3040–3055 plants for single and double crosses, respectively. In each population, proportion of desirable and simultaneous transgressive segregants was estimated. A total of 19 (2.87%), 22 (3.32%) and 24 (3.60%) plants were transgressive in nature simultaneously for multiple traits in single crosses, namely, RAHH‐1755 and RAHH‐455, and double cross, namely, RHDC‐1933, of Group I, respectively. While in Group II, 22 (3.32%), 22 (3.32%) and 24 (3.60%) plants showed simultaneous transgressive segregation in RAHH‐1702, SHH‐818 and RHDC‐1940, respectively. The per cent simultaneous transgressive segregants were found to be higher in the double crosses compared with their respective single crosses, possibly for the reason that double crosses involve more number of parents owing to increased recombination. Hence, breeding for desirable segregating recombinants using diallel and multiple parent‐based approach paves the way towards directional selection based on combining ability making it more efficient compared with conventional means of hybridization followed by selection.