EVALUATION OF GENETIC DIVERGENCE AND HERITABILITY IN WINTER FIELD PEA GENOTYPES

Abstract

The aim and tasks of the study. The research was aimed at studying genetic variability and heritability for various traits of winter pea, which may contribute to selection of genotypes for further breeding programs.Materials and methods. The investigations were carried out at the Institute of Forage Crops (Pleven, Bulgaria) in 2011-2012. The starting materials was eight genotypes - No 58 (Fenn x Pleven 4), No 57 (Fenn x Pleven 4), No 9 (Fenn x Usatyy 90), No 6 (Mir x Kharkovskiy Etalonnyy), No 12A (Mir x Rezonator), No 10 (Kerpo x Mir), No 14 (Pleven 10 x Usatyy 90). Variety ‘Mir’ served as the standard. The plot area was 2 m2 in three replicas. Structural elements of productivity were analyzed for 10 plants. The growing season length was also determined.Statistical processing was performed using analysis of variance (DL Vandev) and hierarchical cluster analysis (JH Ward). The heritability in broad sense was determined by the I. Mahmud and HH Kramer’s formula; the coefficients of genotypic and phenotypic variation - by the M. Fikreselassie’s formula.Results and discussion. Analysis of variance confirmed significant differences for all parameters, except for ‘seed weight per plant’. Small differences were observed between the coefficients of genotypic and phenotypic variation for the traits of ‘plant height’, ‘pod number per plant’ and ‘seed number per pod’. This suggests that the variability of these traits is linked to genetic factors. For ‘1000-seed weight’, variability is due to environmental factors.High coefficients of heritability in broad sense were obtained for the growing season length (98%), plant height (62%), pod number per plant (42%), and 1000-seed weight (42%). These data do not partially tally with other investigators’ ones, which may indicate that the heritability coefficients are valid only for a given population under given conditions. The centroid method determined that line No 10 was low adaptable by the pod and seeds numbers per plant; line No 57 - by seed weight and plant biomass. Line No 6 was noticeable for high adaptability by the pod seed numbers per plant and growing season length.Conclusions. Analysis of variance showed significant differences between genotypes for all traits, except for ‘seed weight per plant’. The results of analyzing the coefficient of variation showed that genotypic variability determines the growing season length. All the test traits, except for ‘seed number per pod’ and ‘seed weight per plant’ were found to have high coefficients of genotypic variability. This means that these traits can be improved via selection.Line No 6 (Mir/Kharkovkiy Etalonnyy) excelled at high adaptability by the pod and seed numbers per plant and growing season length.