Response to selection, combining ability and heritability of coleoptile length in winter wheat

This paper reports analysis of 7 × 7 diallel crosses using a genotype main effect plus genotype-by-environment interaction biplot for determining cold tolerance at the germination stage in rice. ANOVA indicated that there were highly significant differences among the replications, genotypes, general combining ability (GCA) and specific combining ability (SCA) for percentage of reduction in radicle length (RL), coleoptile length (CL) and germination percentage (GP). The hybrid Neda × Hassani had the highest mid-parent heterosis for RL, CL and GP (–58.84, –68.47 and –80.77%, respectively). This result indicated that the reduction of three traits in crosses of Neda × Hassani was lower than their parents. The graphical representation by biplot analysis allowed a rapid and effective overview of GCA and reveals that Deilamani was an ideal general combiner for all traits and this parent is a superior variety for these three traits. Three potential heterotic groups are suggested for RL reduction. Four potential heterotic groups were identified for the two other traits, in the biplot. The first two principal component (PC) axes in the biplot for reduction in GP explained 85% of the variation with first and second principal components (PC1 and PC2, respectively). An important inference that can be drawn from these results is that cross combinations involving Hassani and Deilamani as one of the parents recorded desirable SCA effects for all or most of the studied traits. The information obtained from this experiment can facilitate the identification of hybrids that combine cold resistance traits in rice.

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Combining ability and gene action studies for yield-contributing traits in crosses involving winter and spring wheat genotypes

Acta Agronomica Hungarica ◽

10.1556/aagr.57.2009.4.4 ◽

2009 ◽

Vol 57 (4) ◽

pp. 417-423 ◽

Cited By ~ 1

Author(s):

S. Sharma ◽

H. Chaudhary

Keyword(s):

Winter Wheat ◽

Spring Wheat ◽

Combining Ability ◽

Gene Action ◽

Block Design ◽

Additive Gene Action ◽

Wheat Genotypes ◽

Diallel Mating Design ◽

Additive Gene ◽

Wheat Hybrids

The success of winter × spring wheat hybridization programmes depends upon the ability of the genotypes of these two physiologically distinct ecotypes to combine well with each other. Hence the present investigation was undertaken to study the combining ability and nature of gene action for various morpho-physiological and yield-contributing traits in crosses involving winter and spring wheat genotypes. Five elite and diverse genotypes each of winter and spring wheat ecotypes and their F 1 (spring × spring, winter × winter and winter × spring) hybrids, generated in a diallel mating design excluding reciprocals, were evaluated in a random block design with three replications. Considerable variability was observed among the spring and winter wheat genotypes for all the traits under study. Furthermore, these traits were highly influenced by the winter and spring wheat genetic backgrounds, resulting in significant differences between the spring × spring, winter × winter and winter × spring wheat hybrids for some of the traits. The winter × spring wheat hybrids were observed to be the best with respect to yieldcontributing traits. On the basis of GCA effects, the spring wheat parents HPW 42, HPW 89, HW 3024, PW 552 and UP 2418 and the winter wheat parents Saptdhara, VWFW 452, W 10 and WW 24 were found to be good combiners for the majority of traits. These spring and winter wheat parents could be effectively utilized in future hybridization programmes for wheat improvement. Superior hybrid combinations for one or more traits were identified, all of which involved at least one good general combiner for one or more traits in their parentage, and can thus be exploited in successive generations to develop potential recombinants through various breeding strategies. Genetic studies revealed the preponderance of additive gene action for days to flowering, days to maturity and harvest index, and non-additive gene action for the remaining six traits.

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