Combining Ability of Different Agronomic Traits and Yield Components in Hybrid Barley
Selection of parents based on their combining ability is an effective approach in hybrid breeding. In this study, eight maintainer lines and nine restorer lines were used to obtain 72 crosses for analyzing the general combining ability (GCA) and special combining ability (SCA) for seven agronomic and yield characters including plant height (PH), spike length excluding awns (SL), inter-node length (IL), spikes per plant (SP), thousand kernel weight (TKW), kernel weight per plant (KWP) and dry matter weight per plant (DWP). The results showed that GCA was significantly different among parents and SCA was also significantly different among crosses. The performance of hybrid was significantly correlated with the sum of female and male GCA (TGCA), SCA and heterosis. Hu1154 A, Mian684 A, 86F098 A, 8036 R and 8041 R were excellent parents with greater general combining ability. Five crosses, Hu1154 A×8032 R, Humai10 A×8040 R, Mian684 A×8037 R, Mian684 A×8041 R and 86F098 A×8037 R, showed superior heterosis for most characters.
Combining ability of salinity tolerance on the basis of NaCl-induced K+ flux from roots of barley
Salinity is a major abiotic stress affecting agricultural production. To understand the genetic behavior of salinity tolerance traits, a half-diallel cross was made among six barley cultivars (Hordeum vulgare L.), with contrasting levels of known tolerance, to study the combining ability of salinity tolerance on the basis of K+ loss from plant roots under saline conditions. The glasshouse pot experiments showed that the six parents were significantly different in salinity tolerance and those tolerances were highly correlated with the K+ flux measurements. The combining ability analysis showed that the variances of both general combining ability (GCA) and specific combining ability (SCA) were highly significant. Two tolerant cultivars, CM72 and Numar, showed significantly higher GCA for salinity tolerance (less K+ loss under salinity stress). Cultivars with medium GCA were YU6472 and Yan90260. Salinity tolerance was mainly controlled by additive effects with the tolerance allele showing partial dominance. High positive SCA was also found between two tolerant cultivars and between tolerant and medium-tolerant cultivars, indicating possible different tolerant genes or some minor genes in these cultivars. The combination of these genes from different sources of tolerant cultivars should produce cultivars with even greater tolerance. © Crop Science Society of America. All rights reserved.
Genetic Analysis of Yield and its Component Traits in Barley
Combining ability analysis in six-rowed barley (Hordeum vulgare L.) involving 10 diverse parents and their 45 F1's and F2's progenies indicated significant differences among the parents for gca and crosses for sca for all the characters studied. The gca and sca components of variance were significant for all the traits. The gca:sca ratio showed that among the two types of genetic effects, the non-additive gene effects were more important in comparison to additive gene effects in controlling the inheritance of the characters under study. Among the parents RD 2052, RD 2503 and BL 2 were the best general combiners for grain yield and average to high combiners for other important traits. The best specific crosses for grain yield were BL 2 x ISBYT 17, RD 2503 x RD 2585, BL 2 x ISBYT 4, RD 2052 x BL 2, RD 2508 x ISBYT 4, RD 2053 x RD 2552, RD 2035 x RD 2052 and RD 2035 x BL 2 in both F1 and F2 generations. To ensure further increase in grain yield, combinations of desirable yield components is advocated. The exploitation of additive and non-additive gene actions through bi-parental mating and/or diallel selective mating systems are suggested for tangible advancement of grain yield in barley.