Analysis of genetic diversity in caigua (Cyclanthera pedata (L.) Schrad.) in mid-hill of the Indian Himalayas

The genetic diversity of Cyclanthera pedata was assessed through agro-morphological, mineral composition and biochemical traits. Field surveys across India documented its wide ecological distribution (18.66 degrees-31.02 degrees N, 78.05 degrees-83.27 degrees E, 131-3665 m AMSL) in Andhra Pradesh and northwest Himalayan region. Field evaluations were conducted during Kharif 2021 and 2022 at ICAR-Vivekananda Parvatiya Krishi Anusandhan Sansthan, Almora (1250 m AMSL). Significant genotypic variation was observed in fruit yield (195-1505 g/plant), fruit numbers (36-364 per plant), chlorophyll content (0.49-2.61 mu g/g) and antioxidant activities (16.02-39.04 mM Trolox equivalent/g DW). Notable genotypes included RK-40 (highest yield of 1505 g/plant), RK-01 (early flowering) and RK-33 (early fruiting). High coefficients of variation (>23%) were noted in total chlorophyll, carotenoids and FRAP values. Genotype RK-42 excelled in antioxidant activities and carotenoids. Hierarchical cluster analysis grouped the germplasm into four clusters based on critical traits independent of geographic origin. In contrast, principal component analysis identified traits like polyphenols, antioxidants, seed weight and fruit yield as significant contributors to phenotypic variation. The biplot revealed relationships between traits, such as positive correlations between fruit yield, fruit and pulp weight, and biochemical traits like DPPH and ABTS. Genotypes such as IC 430006, IC 356007, IC 393261, IC 393308, UKAl 1 and IC 361297 display distinct profiles. These findings highlight critical traits for breeding and conservation efforts, particularly for enhancing fruit yield and biochemical attributes in C. pedata germplasm.