COMBINING ABILITY AND HETEROSIS ESTIMATES FROM LINE X TESTER MATING DESIGN UNDER WATER STRESS CONDITIONS IN RICE (Oryza sativa L.) | ||||
| Journal of Plant Production | ||||
| Article 13, Volume 3, Issue 12, December 2012, Page 3117-3137 PDF (629.72 K) | ||||
| Document Type: Original Article | ||||
| DOI: 10.21608/jpp.2012.85374 | ||||
 View on SCiNiTO | ||||
| Authors | ||||
| H. M. Hassan; S. A. A. Hammoud; A. M. El-Moghazy; A. B. El-Abd | ||||
| Rice Research Section, Filed Crops Research Institute, ARC, Giza, Egypt. | ||||
| Abstract | ||||
| A Study on combining ability and heterosis were conducted on 15 F1 hybrids along with eight rice genotypes (five lines and three testers) to understand the pattern of inheritance of yield, its components and some root traits for selecting superior genotypes. The experiment was carried out using line x tester mating design, during 2010-2011 rice growing seasons at the experimental farm of Rice Research and TrainingCenter, Sakha, Kafr El-Sheikh, Egypt. Analysis of variance revealed significant differences among genotypes, lines, testers and line x tester interactions for days to 50% heading, plant height, panicle length and weight, number of filled grains/panicle, number of panicles/plant, number of roots/plant, root length and volume and grain yield/plant traits under water stress conditions, indicated that the genotypes had wide genetic diversity for the studied traits. Significance of the means of sum squares due to lines and testers indicated a prevalence of additive variance. However, significant differences due to interactions of line x tester for the above mentioned traits, indicating the importance of both additive and non-additive variance in the inheritance of these traits. The mean squares due to GCA as well as SCA were significant for all studied traits except 100- grain weight and root/shoot ratio. Thus, the significance of GCA (variances due to lines and testers) and SCA (variances due to lines x testers) implied that both additive and non-additive types of variation was available for all the traits, yet additive genes were more important than the dominant genes because variance due to GCA was higher than that of SCA for all mentioned traits. Moreover, the ratio of GCA and SCA variances was greater than unity for all the traits studied that revealed the preponderance of additive gene action over the non-additive gene action. IET 1444, Morobrekan and Giza 178 rice genotypes were the best general combiners due to highly significant GCA effects for number of roots/plant, root volume and root length traits. Moreover, Wab 450-JR-4-1-1 as tolerant to water stress conditions was the best general combiner for panicle weight, number of filled grains/panicle, otherwise, Sakha 102, rice genotype was the poorest combiner comparing with other rice genotypes for all the studied traits, except days to 50% heading. The crosses, Sakha 105 x IET 1444, Sakha 103 x Sakha 102 and Morobrekan x Wab 450-JR-4-1-1 were found to be the best cross combinations for most of the studied traits; these crosses had high and significant SCA in desirable direction under water stress conditions. Highly significant and positive estimates of heterosis and heterobeltiosis were recorded in Morobrekan x IET 1444, Sakha 105 x IET 1444 and Sakha 104 x Sakha 102 for number of panicles/plant, panicle length and number of roots and their volume/plant, respectively. The highest estimated values of phenotypic (Vph) and genotypic (Vg) variances were observed for number of filled grains/panicle, root number/plant and root volume indicating better scope for the genetic improvement in these three mentioned traits. High broad-sense heritability, coupled with high genetic advance, were observed for plant height, panicle weight, number of panicles/plant, sterility % and grain yield/plant, indicating the role of additive genetic variance in the expression of these traits and direct selection might be highly effective in early generations to improve these traits under water stress conditions. | ||||
| Keywords | ||||
| rice; combining ability; water stress conditions; heterosis; yield; root traits and line x tester design | ||||
|
Statistics Article View: 217 PDF Download: 413 |
||||
