Heterosis in multiple environments for yield components and its relation with genetic divergence in cotton

Heterosis for four major yield components of G. hirsutum L. cotton was estimated in a half diallel cross of nine genetically diverse parents. The heterosis in a single environment was 102.3% for boll number, 51.6% for boll weight and 1393 and 169.4% for seed cotton and lint yield, respectively. Boll number appeared to be the major component of yield heterosis. G X E interaction was detected for all the four traits studied. The hybrids Laxmi X Kop-557 at Rahuri, Kop 557 X Kh-2 and Kop-557 X AC-738 at Padegaon, and Kop-557 X Kop-495 at Jalgaon, were most heterotic, while Reba-B-50 X Kh-2 and Laxmi X MCU-5 with standard heterosis of 47.1 and 25.3%, respectively, for seed cotton yield over H-4, were most promising. High heterotic crosses are not necessarily high yielding. While selecting parents for hybrid breeding programme on the basis of genetic divergence, their per se or cluster mean performance also needs to be considered.