Determination of Genetic Variability and Divergence for Root Yield and Quality Characters in Temperate Radishes

Abstract

There is a need to study variability and divergence for horticultural traits in temperate radishes (Raphanus sativus L.) to develop new cultivars for commercial cultivation in Himachal Pradesh. The study was carried out at the Experimental Farm of the Department of Vegetable Science, Dr. Y.S. Parmar University of Horticulture and Forestry, Nauni, Solan, India, during the months of September–January in 2009–2010. Plant material consisted of 35 temperate environment radish genotypes. Observations were made on plant emergence, days to marketable maturity, number of leaves, leaf length, leaf width, root color, root shape, root/top ratio, root length, root diameter, average root weight, crown diameter, dry matter, and contents of total soluble solids, ascorbic acid, total sugar, and fiber. Genotype affected all characters. Genotype CGN-17290 had 51% more yield over the check ‘White Icicle’ and performed better for plant emergence, days to marketable maturity, leaf length, leaf width, root/top ratio, root length, dry matter, average root weight, and fiber content. Genotypes CGN-23811, CGN-11997, and CGN-11994 performed better than the check for total soluble solids, ascorbic acid, and total sugar. High coefficients of variability (phenotypic and genotypic) were found for root length, average root weight, total soluble solids, root/top ratio, fiber content, and total sugar, indicating close association between phenotype and genotypes. High heritability (h 2), with moderate to high coefficients of variability, and genetic gain were recorded for all characters except plant emergence and days to marketable maturity, indicating a role of additive gene action for their inheritance and the possibility of improvement through selection. There was moderate genetic divergence among genotypes. Genotypes could be grouped into four clusters. The highest intercluster distance was between clusters II and IV, and hybridization between entries in these clusters can be utilized for developing transgressive segregants in subsequent generations. Variety CGN-17290 appeared to be the best genotype, followed by ‘CGN-23811’, ‘CGN-11997’, and ‘CGN-11994’, for yield and quality characters of temperate radishes and can be used in breeding programs to improve yield and quality of temperate radishes.