Comparison of morphological and molecular variation in seeds and seedlings of radish cultivars

Radish (Raphanus sativus L.) is an important vegetable crop around the world and it is very popular in Asia. Lack of uniform products reduces profitability for seed producers and farmers and this may be due to variation in seed quality. Variation is due to genetic and environmental factors and the aim of this research was to determine phenotypic and genetic variability and correlate phenotypic characters with molecular markers. Seeds of seven radish cultivars, Pyuthane Red, Mino Early, White Neck, 40 Days, and Tokinasi from Nepal, and Fire Ball and Long White Chinese from USA were examined. Individual seed were weighed and growth parameters were measured in 100 individuals of each cultivar. A positive correlation between individual seed weight and fresh weight and leaves/plant from 6-day to 4-week old-seedlings was observed. Differences in seed size influenced variation in seedling size, vigour and plant growth. RAPD analysis was used to study the genetic variation at a molecular level within and between cultivars. Ten primers yielded polymorphisms within and between varieties. Some polymorphisms were consistent within varieties while others differed between genotypes. The morphological and genetic data were correlated using multivariate analysis. DNA markers were associated with morphological traits, which would be helpful in seedling selection of interesting traits. Seed grading, improved genetic purity and marker-assisted selection will be helpful in future breeding and selection to reduce morphological variation and increase uniformity of radish.