A comparative assessment of morphological and molecular diversity among Sechium edule (Jacq.) Sw. accessions in India

Genetic variation of 36 Sechium edule accessions collected across 12 states in India was assessed using morphological traits and DAMD markers. Eighteen fruit morphological traits (both qualitative and quantitative) were evaluated to confirm the variations in the present collection. Quantitative traits showed major variations with respect to fruit weight (7.85-498.33 g/fruit), fruit length (5.8-15 cm/fruit), fruit diameter (6-28 cm/fruit) and length of the spine (0-5 cm). Qualitative traits were also diverse in fruit colour, shape, spine density, reticulation, flexibility of spine and furrow depth. The first six principle components showed 82.88% variation in the principal component analysis. The principal component analysis revealed that fruit weight, fruit width, fruit diameter, fruit shape, length of spine, spine density and furrow depth had a significant contribution to the total variation. The DNA analysis performed using DAMD primers were used for deducing the diversity at DNA level. The collection produced 102 bands out of which 97 were polymorphic and the percentage polymorphism ranged between 66.66 and 100 per primer. Discrete pattern of clustering was obtained using UPGMA method of complete linkage percent disagreement revealing high diversity among the collected accessions. Thus, the present study indicates that molecular and morphological marker map would improve our knowledge of S. edule and would facilitate efforts to breed improved S. edule cultivars.