Genetic Variance Revealed in Cowpea by Partial Diallel and Factorial Mating Designs

Abstract

Genetic variability and heritability are two important factors for plant improvement programs where the magnificence and type of this variability determine the selection criteria to be used by the breeder. This study aimed to estimate the genetic components associated with variance and covariance based on partial diallel crosses and factorial mating designs, as well as, to identify the association between yield components and other quantitative traits to extend an orientation for selection. Six cowpea varieties were used in this study. All possible crosses were done according to partial diallel mating design in addition to the F1 hybrid which were arranged in a factorial mating design. The parents, F1 and their F2 generations were evaluated in a field trial experiments at El-Baramon station, Dakahlia Governerate, in a randomized complete blocks design with four replicaties. The results revealed that both two mating designs were suitable to study the genetic parameters. The means of F1 hybrids exceeded the mid parents (MP) and the better parent (BP). Significant values of heterosis were obtained for all studied traits. The highest values were 43.84% for pod length versus MP and 15.68% for number of pods per plant versus BP. The magnitude of both additive and non-additive genetic variances were high that means the possibility to development inbred lines of cowpea through selection. The higher values of broad-sense and narrow-sense heritability indicating good genetic variability for effective selection. The following traits; pod length, pod weight, weight of 100-seeds, and number of seeds per pod could be considered in breeding for grain yield, as they contribute significantly to its improvement.

Diallel analysis of cowpea [<i>Vigna unguiculata</i> (L.) Walp.] for seed size, and resistance to <i>Alectra vogelii</i> Benth.

“…The high narrow sense heritability for 100 seeds weight reported in this study is in agreement with the findings of previous studies where medium to high narrow sense heritability effects were reported (Lopes et al, 2003;Idahosa et al, 2010;Tignegre, 2010;Egbadzor et al, 2013;Ameen et al, 2014). However, predominant non-additive effects indicating low heritability was also reported for this character (Raut et al, 2017).…”

Relationships between Hybrid Performance and Genetic Distance Revealed by Morphological and Molecular Markers in Cowpea (Vignaunguiculata (L.) Walp)

“…Similar finding was reported by Ameen et al (2014), who found higher values of broad-sense and narrow-sense heritability indicating good genetic variability for effective selection in cowpea. High heritability value for 100-seed weight, vegetable pod yield and pod weight were reported by Resmi (1998) and Thiyagarajana (1989).…”

“…The dominance variance (H 1 ) was higher than the additive variance (D) for all traits except TF, WP, WS and TS, these results are in agreement with Mohamed et al (2015). The results illustrated that diallel crosses appeared the relative magnitudes of mean squares for GCA variances in F 1 hybrids and F 2 generations which were larger than those of SCA for all traits in cowpea (Ameen et al, 2014). Supriyo et al (2010) reported that the magnitude of nonadditive gene effect was higher than that of additive gene effect for each studied trait in black gram.…”