Development of RAPD and ISSR markers for genetic diversity analysis in pointed gourd

Abstract:

Pointed gourd (Trichosanthes dioica Roxb.) occupies roughly 42,500 hectares of Bangladeshi vegetable acreage yet lacks a systematic picture of its genetic base, leaving breeders to work with unclear parental material. This research screened 24 pointed gourd accessions, collected across five agro-ecological zones between July 2021 and December 2022, using 30 RAPD and 18 ISSR primers. After quality filtering, 15 RAPD and 12 ISSR primers were retained for full-scale profiling. RAPD markers produced 218 amplicons (72.5% polymorphic) with an average polymorphism information content (PIC) of 0.37, while ISSR markers produced 196 amplicons (78.1% polymorphic, PIC = 0.42). ISSR outperformed RAPD on reproducibility (re-run concordance 94.2% versus 81.6%) but RAPD detected a small set of rare bands. Jaccard similarity values ranged from 0.29 to 0.86 across accession pairs. UPGMA clustering split the panel into four groups that aligned broadly with geographic origin, with two accessions from the Barind tract forming a distinct sub-cluster. Combined RAPD-ISSR fingerprints separated all 24 accessions unambiguously, pointing to a combined-marker strategy for downstream germplasm management and parent selection.