Assessment of genetic diversity of ninety-one bottle gourd [Lagenaria siceraria (Mol.) Standl.] genotypes from fourteen different agro-climatic zones of India using agro-morphological traits and SSR markers.

BACKGROUND: The evaluation of the magnitude of genetic diversity present in the germplasm collection is prerequisite for bottle gourd improvement programme. The characterization of the diversity pattern of Indian bottle gourd accessions will facilitate the optimal use of genetic resources for breeding improved cultivars. METHODS: In the present study, the magnitude of genetic diversity was evaluated in ninety-one genotypes of bottle gourd collected across fourteen different agro-climatic zones of India. RESULTS: Significant variations were observed for all the studied ten quantitative and nine qualitative traits. The ninety-one genotypes were grouped into nine clusters based on cluster analysis of morphological characteristics. Eigen value from principal component analysis depicted first seven quantitative traits accounted for more than 97.5 cumulative percent of the total variations. The first two components accounted for 50 cumulative percent of the total variation, which signifies a high degree of correlation between the analyzed traits. Molecular diversity with the 40 SSR markers screened revealed 11 polymorphic markers in the genotypes studied. Population structure analysis divulged five populations, conforming to the Principal Coordinate Analysis. Molecular analysis revealed genetically diverse genotypes along with the morphologically divergent genotypes from the quantitative traits and highest inter-cluster distance would be the most appropriate parents for exploiting heterosis. CONCLUSIONS: The results of this study will facilitate the optimal use of genetic resources for breeding improved cultivars of bottle gourd and the adoption of the identified superior genotypes directly by the breeders.

Genetic diversity and population structure detection in sponge gourd (Luffa cylindrica) using ISSR, SCoT and morphological markers.

Investigation of genetic diversity is essential for the selection of parents for crop breeding and conservation of genetic resources. To estimate the genetic variability and population structure in the midst of 45 accessions of sponge gourd brought together from different geographical areas of India, morphological traits and two molecular markers, ISSR and SCoT markers were compared. Principal components analysis of 20 morphological traits showed 72.70% variability and significant positive correlations between fruit traits. All three marker techniques clustered all accessions into two groups with few outgroups. High level of polymorphism was observed among ISSR (74.6%) and SCoT (71.5%) primers. The Bayesian model revealed the hidden grouping and showed admixture type of population. The diversity pattern is influenced by genetic marker used, as different molecular markers have different polymorphism evaluation efficiency. This study can be helpful in amplifying the genetic base and selection of specific traits for breeding. Thus, ISSR and SCoT markers are potential marker for identification in sponge gourd and provide valuable data on its genetic correlation and structure.

Simple cryopreservation protocol for Luffa pollen: enhancing breeding efficiency.

This study aimed to develop a long-term pollen storage protocol for Luffa species (L. acutangula, L. cylindrica, L. echinata, and L. graveolens) and assess its potential for crop improvement. The optimal medium for in vitro pollen germination varied by species, with Brewbaker and Kwack (BK) medium with 10% sucrose suitable for L. acutangula, L. cylindrica, and L. echinata, and BK medium with 3% sucrose ideal for L. graveolens. Overestimation in staining tests compared to in vitro pollen germination was observed. The best results for cryopreservation were achieved with desiccation periods of 20, 30, and 40 min, maintaining moisture content between 14.04% and 18.55%. Pollen viability was negatively correlated with storage temperature (25, 4, and -20°C) and duration. Cryopreserved pollen at -196°C exhibited the highest viability over a prolonged period (2 months) and was comparable to fresh pollen in terms of germination, ovule fertilization, and fruit and seed set. This study presents a simple and reproducible pollen cryopreservation protocol applicable across Luffa species, facilitating long-term storage and its use in crop improvement efforts.