Morphological Characterization and Genetic Diversity Assessment of Seven Radish (Raphanus Sativus L.) Genotypes Based on Germination, Root, and Leaf Traits

Radish (Raphanus sativus L.) is a globally important root vegetable whose breeding progress depends on the availability and systematic characterization of morphologically diverse germplasm. In the present study, seven locally maintained radish genotypes — Red Neck Purple, Green Neck, Mino Local, Lal Pari Round, Lal Gol, Sufaid Pari, and Guang Suang — were evaluated for germination behaviour and twelve quantitative root and leaf traits recorded at the root-development and harvest stages. Data were analysed in R (v4.3.3) using descriptive statistics, Pearson correlation, principal component analysis (PCA), and hierarchical cluster analysis (Ward's method). Genotypes differed markedly in germination percentage (20–98%), root length (12.5–32.4 cm), root girth (11.2–25.0 cm), leaf area (127.4–559.8 cm²), and single root weight without leaf (0.10–0.38 kg), with coefficients of variation ranging from 25% to 80% across traits. Root length was strongly positively correlated with root weight (r = 0.78) and number of leaves (r = 0.77), and strongly negatively correlated with root girth (r = -0.77), indicating a length–girth trade-off in root development. Leaf length, leaf width, and leaf area were tightly inter-correlated (r = 0.70–0.93), reflecting coordinated canopy expansion. The first two principal components jointly explained 86.8% of total morphological variance, and cluster analysis grouped the genotypes into three morphologically distinct clusters, separating the slow-emerging, low-germinating Guang Suang and the large-leaved Lal Pari Round from the remaining genotypes. These results demonstrate substantial exploitable morphological diversity among the studied radish genotypes and identify root length, root girth, and leaf area as the most discriminating traits for genotype selection in future radish breeding and germplasm conservation programmes.