Assessment of genetic variability, diveristy and association in fifteen bread wheat genotypes

الملخص EN

The present work was conducted at Nubaria Research Station Farm to assess the genetic behavior of fifteen bread wheat genotypes during the two growing seasons of 2013/2014 and 2014/2015.

The experimental design used was a randomized complete block design, with three replicates.

The Analysis of variance and covariance were computed to estimate broad sense heritability (h2).

Also, genotypic and phenotypic correlation coefficients and path analysis were computed between grain yield and its related characters, as well as cluster analysis was automated to identify the interrelationships among the tested genotypes.

Results showed significant differences among wheat genotypes for all studied characters in the first and second seasons and across the two seasons.

Genotypes No.

2, 6 and 11 outyielded the average grain yield of the three check cultivars (Giza 168, Sids 12 and Misr 1) by 25, 6.07 and 12.35 %, respectively, indicating their magnitude as promising genotypes that could be recommended for release.

Large values of h2 couple yield.

Highly significant and positive correlation coefficients were detected between grain yield and each of number of spikes/m2 followed by number of kernels/spike at the genotypic and phenotypic levels.

Also, path analysis showed that number of spikes/m2 and number of kernels/spike gave the maximum influence directly and indirectly upon grain yield in wheat crop.

As a result, the above mentioned characters could be used as selection criteria in wheat breeding program.

The cluster analysis classified the tested genotypes into four main different groups (clusters), where each group contained the genotypes which showed similar phenotypic performance.

It is clear that the second cluster included the maximum number of items (seven out of fifteen genotypes), followed by the third cluster (four genotypes) and the first cluster (three genotypes) and finally the fourth (two genotypes).

Accordingly, the results exhibited the presence of considerable genetic diversity among the tested genotypes, which gave a good chance to achieve sufficient steps for genotypic improvement of wheat through the hybridization among genotypes, taken from divergent clusters