Floral Characteristics and Reproductive Biology in Brazilian Melon Accessions: Insights from Commercial and Exotic...

Melon has great economic importance in Brazil, and flower development is the basis for fruit and seed production. The objective of this study was to elucidate the variability of flowering characteristics and to compare qualitative and quantitative reproductive variations in relation to pollen viability and stigmatic receptivity in 21 genotypes, which includes 15 Brazilian accessions. In addition, we evaluated the influence of time on the growth of the pollen tube and its arrival at the ovule in vivo at different intervals (1 h, 2 h, 3 h) after hand pollination in three commercial varieties, one exotic accession, and two intervarietal hybrids, by epifluorescence technique. Three groups were distributed by the clustering method of Scott-Knott at 5% probability; group III included only commercial varieties for the flower width descriptor. C. melo germplasm presented 81% andromonoecious plants and 19% trimonoecious plants. Through the multivariate strategy, these 21 genotypes were distributed into six groups with distinct reproductive characteristics, and male flowering was accelerated compared to female flowering. Regarding pollen viability, it was greater than 95% according to staining methods. Pollen germination rate in vivo was affected by time, with an almost 12.5% increase between 1 h and 3 h after hand pollination, and the in vivo pollen germination in hybrids was lower than in commercial varieties. Brazilian accessions, despite stability in pollen viability and stigma receptivity, have great differences in reproductive terms, such as variations in the quantitative and qualitative characteristics of floral pieces and flowering. This work contributes to the knowledge on varieties, hybrids, exotic accession, and Brazilian melon germplasm by characterizing some of their main agricultural traits, such as reproduction floral biology, and opens up prospects for yield evaluation in plant breeding programs.