Nature of gene action and combining ability for yield and its related traits in hybrid rice

Oryza 05/2011; 4:288-296.


A study was undertaken with a fixed effect model i.e. line x tester mating design involving 3 CMS line and 20 elite genotypes of rice to identify heterotic combinations expressing high hybrid vigour. On the basis of overall performance the male lines, IR 35454-18-1-1-2R followed by IET 201108 and IR 52256-9-2-2-1R were identified as most promising parents having good general combining ability for grain yield and major components. Out of 60 crosses, about 30% crosses showed significant and desirable sca effects for grain yield along with its three important traits, viz., number of fertile spikelets, number of spikelets per panicle and biological yield. The crosses NMS 4A x IR 633-76-1R, IR 58025A x IR 19058-107-1R, IR 58025A x IR32419-28-3-1-3-3R, NMS 4A x IR35454-18-1-1-2R and NMS 4A x IR 5226-9-2-2-1R exhibited high estimates for parents and good sca effects, hence, they may be considered for hybrid breeding programme. The higher magnitude of sca than gca variance, greater values of average degree of dominance and lower predictability ratio was observed in all the characters studied. This suggested significant role of non-additive gene action which resulted from dominance, over dominance, epistatic and various other interaction effects. Results on gene action and combining ability indicated that both general and specific combining ability effects are important but predominance of non-additive genetic variance indicated the presence of heterozygosity in the population.

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Available from: Praveen Pandey, Aug 21, 2014
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    • "Therefore, Kempthorne (1957) suggested line × tester analysis as a faster and more reliable method to estimate combining ability and screen suitable lines for hybridization. Since then, many researchers have used line × tester analysis for hybrid rice genotypes (Kumar, 2007; Saidaiah et al, 2011; Tiwari et al, 2011; Patil et al, 2012; Raju et al, 2012). However, most of these studies have focused on yield and yield components using traditional methods. "
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    ABSTRACT: A study of combining ability for improving rice cooking quality was carried out via genotype plus genotype × environment (GGE) biplot. Four restorer lines and three male sterile lines were used to obtain F1 in a line × tester trial at the Rice Research Institute, Amol, Iran in 2009. GGE biplot analysis showed that Neda and IR56 were the best general combiners for amylose content (AC), whereas Nemat and IR28 had the highest general combining ability (GCA) effects for gelatinization temperature (GT), and IR58 and IR59 showed the highest GCA effects in terms of gel consistency (GC). Meanwhile, IR58 and IR59 showed large specific combining ability (SCA) effects for AC, while Neda and SA13 had high SCA effects for GT. Nemat and IR28 had large SCA effects for GC. Because intermediate levels of AC, GT and GC are ideal, Nemat × IR59 was considered as the best possible cross. Based on these results, the GGE biplot showed good potential for identifying suitable parents, heterotic crosses and the best hybrids in line × tester data.
    Rice Science 09/2014; 21(5):282-287. DOI:10.1016/S1672-6308(13)60193-6