Genetic differentiation of bottle gourd [Lagenaria siceraria (Molina) Standl.] landraces assessed by fruit qualitative traits and simple sequence repeat markers

Abstract

Phenotypic and genotypic characterization of plant genetic resources is fundamental for breeding and strategic conservation. This study assessed the genetic diversity present in bottle gourd landraces using 10 fruit qualitative traits and 11 simple sequence repeat (SSR) markers. Thirty six South African bottle gourd landraces collected from various geographic locations were used for the study. Phenotypic diversity was estimated using Shannon-Weaver diversity indices, principal component and cluster analyses. Phenotypic diversity index was 0.98, showing high genetic diversity among bottle gourd landraces. Principal component analysis identified four PCs which contributed for 75.3% of the total phenotypic variation. Presence or absence of fruit neck, fruit shape, degree of neck bending and fruit neck length positively correlated with PC1, which accounted for 37.6% of the total variation. Primary fruit colour and fruit texture highly correlated with PC2 which accounted for 15.78% of the total variation. Number of alleles varied from 3 to 9 with a mean of 6 per SSR locus. Number of effective alleles ranged from 1.99 to 6.72 with a mean of 3.75. Expected heterozygosity values ranged from 0.5 to 0.87 with a mean of 0.71 with polymorphic information content varying from 0.5 to 0.85 and a mean of 0.7. Qualitative traits and SSR markers analyses had significant correlation (r=0.15, P=0.02) in clustering the landraces. The present study revealed that fruit qualitative traits are useful attributes in bottle gourd breeding and genetic analysis.