Studies of Heterosis for Exploitation of Heterotic Boxes in Seed Cotton Yield and its Attributing Characters

Abstract

One hundred twelve inter specific hybrids between G. hirsutum x G. barbadense derived from twenty eight G. barbadense lines and four G. hirsutum testers DH 98-27 (T 1 ), ZCH 8 (T 2 ), 178-24 (T 3 ) and DH 18-31 (T 4 ) were evaluated to study heterosis for seed cotton yield and its component traits. Significant heterosis was observed for the characters under study indicating the presence of genetic diversity among the parental lines. For seed cotton yield, thirty crosses showed significant positive heterosis and only one cross showed significant negative heterosis over their mid parent. The cross DH 98-27 X (DB 533 x DB 534 F 4 IPS 49) (39.97) recorded highest significant positive heterosis over commercial Bt check MRC 6918 and the cross 178-24 X (DB 533 x DB 534 F4 IPS 33) (-44.37) exhibited lowest significant negative heterosis over MRC 6918. Two crosses showed significant heterosis in positive direction and two crosses showed significant heterosis in negative direction over MRC 6918. In case of DCH 32 non Bt check, the cross DH 98-27 X (DB 533 x DB 534 F4 IPS 49) (44.31) showed highest significant positive heterosis over this check, but the cross 178-24 X (DB 533 x DB 534 F4 IPS 33) (-42.65) recorded lowest significant negative heterosis value over DCH 32 commercial check. Two crosses exhibited significant positive heterosis over DCH 32 commercial check and only one cross showed significant negative heterosis.