Elucidation of genetic purity in castor (Ricinus communis L.) genotypes through morphological markers

Abstract

The present investigation was undertaken to assess genetic purity in sixteen genotypes of castor (Ricinus communis L.), which were evaluated in Randomized Block Design (RBD) during the late kharif season of 2020-21 to assess the genetic purity based on morphological character performance. Based on the variations in the shape of seed, fourteen genotypes were grouped as oval and two as elongated. Based on seed coat colour, four genotypes were grouped into light brown, five genotypes as brown and seven genotypes as dark brown. Based on the variations in leaf shape, twelve genotypes were grouped as flat, shallow cup in three genotypes and deep cup in one genotype. Based on the variations in inflorescence: types of flowers on primary spike, twelve genotypes were grouped as interspersed, pistillate in three genotypes and monoecious in one genotype. Based on the variations in spike shape, only one genotype shows umbrella, four are cylindrical and eleven are conical. Based on the variations in spike compactness, only one genotype shows compact, four genotypes as loose and eleven genotypes are semi-compact. Based on the variations in branching pattern, three genotypes showed convergent and thirteen genotypes are divergent. The plant was observed very tall due to environmental factors. The significantly maximum number of spikes per plant was observed in genotypes GCH 9 (7.43) followed by GCH 4 (7.0), GCH 7 (7.0), DCS 89 (7.0) and PCS 124 (7.0) with mean value of 6.42. Whereas, number of capsules per spike was observed in genotypes GCH 4 (65.33) followed by 48-1 (50.84), GC-2 (49.67), JP-96 (48.67) and VP 1(M) (48.00) with mean value of 46.21. The number of seeds per capsule was the same for all genotypes (3). Characters like 100-seed weight, days to flowering, number of nodes on the main stem, length of the primary spike, plant height, days to maturity and seed yield per plant varied significantly among the genotypes. The seed yield per plant ranged from 264.32 (GC 3) to 396.93 g (GCH 8) with a mean of 361.48 g. The seed germination percentage ranged from PCS 124 (67.33 per cent) to GCH 9 (95.33 per cent) with a mean seed germination percentage of 88.66 per cent. The seedling vigour index I ranged from 1434.05 (GCH 9) to 2677.24 (DCS 89) with a mean seedling vigour index I of 2045.07. The seedling vigour index II ranged from 36.98 (PCS 124) to 129.16 (GCH 8) with a mean seedling vigour index II of 84.79.