Abstract
The studies were conducted during December 2007 to May 2010 at Bangladesh Agricultural Research Institute (BARI), Gazipur and four different regional stations i.e. Regional Agricultural Research Station (RARS) at Jamalpur, RARS at Hathazari, RARS at Rahmatpur and Agricultural Research Station (ARS) at Burirhat, Rangpur. The study areas were included identification of parental lines through genetic diversity and combining ability study, selection of heterotic F1 crosses and stability analysis of some promising crosses over five locations for exploiting high yielding hybrids in maize. Forty eight maize inbred lines were evaluated for 11 morpho-agronomic traits at Gazipur in two consecutive years (2007-08 and 2008-09). The lines varied significantly for yield and yield contributing traits. Based on the relative magnitude of the D2 values, all the 48 inbred lines were grouped into 12 and 11 clusters, respectively, under rabi season of 2007-08 and 2008-09. Ten inbred lines were selected based on per se performances and genetic diversity and crossed in a half diallel fashion. The genetic studies suggested the importance of both additive and non-additive gene actions for the expression of yield and yield contributing characters. However, variances due to GCA were much higher in magnitude than SCA for all the characters indicating preponderance of additive gene effects for the inheritance of these traits. Four parents viz. P2(Ki21), P3 {FS8B(T)}, P,(CML298) and Ps(CML285) were found good general combiner for grain yield and other important yield contributing characters. Higher SCA effects for different characters appeared in high high or high average or high × low or average × average GCA effects of the parents. Six crosses viz. P2P8(Ki21×CML285), P3 × P4{FS8B(T) CA34502), P3 x P,{FS8B(T)-CML298}, P3 Pg{FS8B(T)-CML285}, P4 × P8(CA34502×CML285) and Ps x Pg(BML2-CML285) expressed significant and positive heterosis coupled with significant high SCA effects for grain yield and most of the important yield contributing traits. The highest heterosis for kernel yield. was 9.95% over the commercial hybrid variety, NK-40 used as check. The pooled analysis of variance over locations revealed significant difference among the genotypes and environments (locations) for most of the characters. Genotype x location interaction was significant for all the traits suggesting that genotypes interacted significantly with the changing environments. The two crosses viz. P3 x P4{FS8B(T) CA34502) and P4 × Pg (CA34502×CML285) could be considered as stable and selected for commercialization across diverse environments.