Growth Performance and Polyploidy Characterization of M2 Mutants of Black Soybean (Glycine max L.) cv. Detam-2 Induced by Colchicine

Abstract

Background: Black soybean (Glycine max L.) cv. Detam-2 is an important Indonesian cultivar with potential for genetic improvement. Colchicine-induced chromosome variation can generate novel phenotypic and cytogenetic traits, but their expression and chromosome constitution require evaluation in subsequent generations. Methods: A total of 192 M2 plants comprising an untreated control and three mutant groups derived from 3,500 ppm colchicine-treated M1 plants were evaluated at the experimental field of Universitas Islam Riau, Indonesia. Agronomic traits were analyzed using analysis of variance followed by Duncan’s multiple range test at p less than 0.05, while chromosome number and karyotype characteristics were assessed cytogenetically in one randomly selected plant per treatment. Result: Mutant-1, Mutant-2 and Mutant-3 showed greater plant height than the control, reaching 61.32±15.03, 62.20±13.21 and 60.20±11.62 cm, respectively, compared with 33.20±12.30 cm. Mutant-1 and Mutant-2 produced significantly more pods per plant (192.87±32.66 and 193.32±44.51, respectively) than the control (111.12±42.01). Mutant-2 retained the purple-petiole phenotype, whereas Mutant-3 exhibited curly leaves. Cytogenetic analysis identified diploid complements in the control and Mutant-3 (2 n = 40) and triploid complements in Mutant-1 and Mutant-2 (3 n = 60). Karyotypes were predominantly metacentric, with one submetacentric chromosome observed in Mutant-3. Mutant-1 and Mutant-2 therefore represent promising materials for further breeding evaluation, although fertility, chromosome stability, heritability, seed yield and multilocation performance require further validation.