Abstract:

Genetic diversity study among 34 pea genotypes (Pisum sativum L.) was performed using 16 morphological markers and 15 SSR markers. The 34 genotypes included the 7 already adapted varieties of this region, 21 advanced breeding lines and 6 local cultivars. The status of the morphological traits was scored in codes ranging from 1 to 9 as per the National Test Guidelines for the Conduct of Tests for Distinctness, Uniformity, and Stability of Pea (Pisum sativum L.). Among the genotypes evaluated, Matek and DDR-88 have the tallest (117 cm) and shortest (19 cm) mean plant height, respectively. Genotypes which show early flowering were DDR-23 (45 days), E-6 (53 days), Makuchabi (55 days), KPMR-885 (58 days) and late flowering genotypes were Pant P-142, IPFD 09-3 and HUDP-15 (> 80 days). HUDP-15, HUDP-904, KPMR-871 and IPFD 09-2 were leafless and thirty genotypes showed presence of normal leaves. Purple petal colour was observed only in the six local cultivars and the rest were recorded to be white colour petal. The genotypes which showed relatively high yield are Rachna, IPFD 09-2, CAU FP-1, IPFD 1-10 and Pant P-136. Seed weight ranged from 134 g per 1000 seeds (VL-52) to 280 g per 1000 seeds (CAU FP-1). The minimum genetic distance based on morphological marker was 0.00 which were found in DDR-50 with DMR-61, KPMR- 871 with IPFD 1-10 and Pant P-142 with NDP 9-408 showing their close relationship to each other. The maximum genetic distance observed was 0.81 in the genotype E-6 with Apakpi and Pant P 09-2 with Makuchabi with an average of 0.33. The number of alleles per SSR marker varied from 2 to 5, with an average number of 2.866 alleles per locus. Polymorphic information content values (PIC) ranged from 0.105 to 0.560 per locus, with an average of 0.401. Variability among groups (FIS=0.938) and variability within individuals (FIT=0.948) were low due to high fixation index of the alleles. However, there was high variability among the individual genotypes within groups due to low fixation index of the alleles (FST=0.163). The minimum and maximum molecular genetic distances were found to be 0.12 (Pant P-136 with VL-51) and 0.78 (E-6 with LP-4) with an average of 0.41. In cluster analysis, morphological and marker-based GO grouped the local cultivars separately from the advanced breeding lines and adapted varieties. A significant, positive correlation (r=0.219 at p=0.002) between the morphological data and SSR marker-based matrices indicated that SSR genetic distance tended to reflect morphological distance. The diverse genotypes revealed from both the dendrograms were IPFD 09-2, HFP-620, Azad P-1, Matek, IPFD 1- 10, CAU FP-1, IPFD 09-3, Pant P-136, Rachna, E-6, Matek and LP-3. In future, pea improvement through hybridization is being proposed by utilizing the diverse genotypes identified as it may generate ample variability to allow effective selection and maximizing genetic gain. Key note : Fixation index, genetic diversity, genetic distances, Pisum sativum,SSR