Wheat Information Service
Number 96: 20-22 (2003)
Research article
Genetic divergence study in durum wheat based on seed vigor parameters
Raghuvirendra Singh, R.P.S. Kharb and Vikram Singh
Department of Seed Science and Technology, Department of Plant breeding, CCS Haryana
Agricultural University, Hisar-125 004, India
Summary
Genetic divergence by using Mahalanobis D2 statistics was studied for eight seed vigor parameters in 24 durum wheat genotypes. All the genotypes were grouped into six different clusters, which were not related to their geographical origin. It could be suggested that hybridization between parents included in clusters III and II followed by selection in segregating generations may help in isolating the desirable strains with early seedling vigor.Introduction
India is a major durum wheat (Triticum durum Desf.) growing country in the world. It is traditionally grown under rainfed conditions in marginal soils. In such situation, the crop remains in stress right from the sowing to harvesting which results in poor and marginal yields, consequently low average productivity. It is also well known fact that highly vigorous seed performs better under wide range of environmental conditions, particularly stress conditions. For genetic amelioration of this crop, precise information on the nature and degree of genetic diversity helps in making of choice of desirable parents for a meaningful hybridization program. For identifying genetically divergent parents for hybridization, few worker adopt D2 statistics based on yield and its components in tetraploid wheats (Lee and Kaltsiek 1973; Joshi and Singh 1979; Raut et al. 1985; Sethi et al. 1992; Singh 1994; Deshmukh et al. 1999). But no such information is available on the basis of seed vigor parameters, hence an attempt has been made to study the genetic diversity in twenty-four genotypes.Materials and methods
Present study was carried out on twenty-four genotypes (including elite international germplasm nursery strains, advanced breeding line and cultivars) of durum wheat. Various seed vigor tests were employed in seed quality testing laboratory of Department of Seed Science and Technology, CCS Haryana Agricultural University, Hisar (India). The observations were recorded on the following parameters viz. seed density (mass/volume, g/cc), standard germination (ISTA 1996), vigor index-I (germination % x seedling length), vigor index-II (germination % x seedling dry weight), electrical conductivity of seed leachates (mu mhos/cm/seed), accelerated ageing test (41°C, 100% rh, 72 hrs). Field emergence index was calculated following the procedure given by Maguire (1962). The total number of seedlings after 20 days of sowing was considered as seedling establishment potential. Following the ANOVA, the genetic diversity was assessed by using D2 statistics of multivariate analysis given by Mahalanobis (1936) and the method suggested by Tocher (Rao 1952) was used to determine the group constellation.