Genetic diversity of bottle gourd [Lagenaria siceraria (Mol.) Standl.] Genotypes of Eastern India through agro-morphological traits and ISSR markers: implication for future breeding

Genetic characterization of plant genetic resources is a prerequisite for a strategic breeding programme. Bottle gourd is an important cucurbit grown throughout India for its tender fruits used for culinary purposes. For the present investigation, twenty-four genotypes of bottle gourd were collected from Eastern India to examine the magnitude of genetic diversity based on 16 quantitative traits and seven ISSR (Inter Simple Sequence Repeats) markers. In the morphological study, genotypes performed significantly in all traits; however, BRBG-65 (591.10 q/ha) proved to be a high yielder with other attributing traits in a pooled analysis of two growing seasons, compared to all three check cultivars of the region. Almost all the traits under study showed a high percentage of genotypic coefficient of variation, phenotypic coefficient of variation and heritability with genetic advance. Quantitative traits like fruit weight, number of fruits per vine and yield of marketable fruits per vine displayed a strong character association with the yield per hectare. The principal component analysis of quantitative traits depicted six principal components, accounting for 79.33% of the total variations. The first two components accounted for 44.92 cumulative percent of the total variation, signifying a high degree of correlation between the analyzed traits. In the molecular study, the average polymorphism percentage was obtained by the ISSR marker pattern studied by seven primers. Totally, 48 reproducible amplicons were generated, with an average of around 6.85 amplicons per primer. The values of polymorphic information content, major allele frequency, Nei's gene diversity, and Shannon's information index were obtained in a wide range. A wide range of values regarding Jaccard's similarity coefficient was also ensured through ISSR markers. Dendrogram and similarity matrix produced from ISSR data were then compared and confirmed the discrimination among genotypes within these clusters. Most genotypes studied in the present experiment differed according to their geographic origin. The investigation highlights the potential utilization of these germplasms for further genetic analysis.