HETEROSIS AND ITS ASSOCIATION WITH GENETIC ATTRIBUTES USING LINE X TESTER MATING IN RICE (Oryza sativa L.)

Abstract

An investigation was carried out to assess the combining ability effects. heteroses from parent.,; and their hybrids during November. 2007 to November. 2008 at Bangladesh Rice research Institute (BRRI). Gazipur. The analysis of variances were carried oul for 14 agronomic and yield related characters indicated that the genotypes were differed significantly From each other for all the characters studied. Combining ability studies revealed that the specific combining ability (SCA) effects were higher that and general combining ability (GCA) effect for most of the traits except panicle length. primary branch panicle4, spikelet panicle-1 and spikelet fertility which indicated that importance of both additive and non-additive gene actions were governing the inheritance on the coneerncd traits but the non-additive gene action were prcdominant. Among the CMS lines BRRI3A produced significant and desirable OCA effects for shorter plant height. earliness, tiller hill', panicle length (cm) and number of tmicles mete(2 which was considered as a good general combiner for these traits concerned. Similarly, the restorer BRRII2R identi fled as the best general combiner for shorter plant height, earliness and number tiller hill' and the an other restorer line I3RRI I 7R selected as the best general combiner due to their desirable and significant (WA effects for spikelet fertility (%) 1000-grain weight and yield plant". Result indicated that the hybrid combinations 1R73328A113R736. 1132A/BR736R. BRRI I 0Afi3R6723-i - 1-2k and 1132A1BR6839-41-5-IR were found as the best specific combiner for yield plant-'. spikelet fertility (%) and 1000-grain weight for their highly significant and positive SCA values. Ihe combinations IJRRI3A/I3RRI I 7R. 1R73328A/BR6723- I-I -2R, BRRI9A/BR6839-41 -5-I R 13RR1 1 OA/RRI 68R and 1132A/BR827R were also identified as good specific combiner for shorter plant height and earliness due to their significant and negative SCA effects. On the other hand. the hybrids: BRRI3A/13RRJ 12R. BRRI3A/BRRI I 7R. I3RRI9eVBRRII OR. BRRI9A'BRRI 12R and I3RRI9AJBRRII7R manifested significant and desirable heterosis over mid parent. better parent and over standard checks For grain yield plant'. 1000-grain weight, plant height, days to 50% flowering and days to maturity, therefore, these hybrids combinations were selected as the best performer among the combinations evaluated in this study. Considering the character association studies, it was observed that out of 227 significant and desirable SCA effects 69 were produced by High x Low OCA parental conibination, where as the maximum number of heterotic crosses were evolved from I-ugh x Average OCA parental combination for both mid-parent and better parent heterosis.