A seven-parental diallel analysis of nutritional composition of common beans

Abstract

Genetic information on combining ability and the type of gene action that governs the inheritance of economically important quantitative characters can be an immense help to the breeder. Such information can assists the plant breeders in selection of suitable parents and the appropriate breeding procedure. Therefore, a 7 × 7 diallel analysis of combining ability of three nutritional components in beans (Phaseolus vulgaris L.) were conducted. The aim of the study was to obtain information on the inheritance of traits and to identify best parents for hybridization. This study showed that estimates of both the combining ability (general and specific), and reciprocal variances were significant for both protein and tannin content, whereas only reciprocal variance was significant for phytate. The protein and tannin ratios of the general to specific combining ability variances were 1.0 and 2.0, respectively. These values indicated that both additive and non-additive genetic variances are important in the inheritance of protein. However, the magnitude of general combining ability of tannin was higher than the specific combining ability variance, indicating the predominant role of additive genetic variance. The performance of the parents for percent protein content was highly associated with their general combining ability effects. The three parents, BBL 254 (P7), PI 300657 (P4), and BBL 290 (P3) were good general combiners for protein and, thus, could be utilized for breeding high protein genotypes. The best combiners for tannins were BBL 254, BBL 290, N80097 (P5), and Eagle (P1). The best specific combinations for protein were PI 300657 × PI 304833 (P4 × P6), Eagle × PI 304833 (P1 × P6), Eagle × N80097 (P1 × P5), Pinto 111 × PI 300657 P2 × P4), and Eagle × BBL 290 (P1 × P3). Lower tannin content was observed in white-seeded genotypes compared to black or pinto beans. Reciprocal crosses were also significant and desirable for protein, tannin, and phytate values. Therefore, it is suggested that caution should be exercised when selecting male and female parents in hybrid production. Recurrent selection and reciprocal recurrent selection could be suitable breeding procedures for rapid improvement.