Reproductive Diversity in Cultivated Tomato (Solanum lycopersicum L.): Relationships Among Floral, Fruit and Seed Traits.

The extensive diversification of flower shape and organs underpins the adaptive success of angiosperms. Despite substantial knowledge of the molecular mechanisms controlling flower induction and development, few studies have quantified the variability in floral traits within species or explored their correlation with other reproductive traits. In cultivated tomato (Solanum lycopersicum L.), human selection has driven fruit diversification in terms of size and shape. In the present study, 48 landraces representing tomato diversity in reproduction-related characteristics were phenotyped for 18 flower structural or dimensional traits. Flower traits exhibited lower coefficients of variation compared to other reproductive traits, though organ numbers showed high heritability values. Flower organ number and size were tightly correlated, but the correlation between dimensional traits was weaker. This likely reflects the selective pressures on pistil traits during domestication, including specific mutations affecting carpel number and ovary morphology. While ovary and fruit size were positively correlated, no relationship was found between ovule and seed size, suggesting that genes related to seed size generally act after fruit set. The collection was genotyped at the Fasciated (Fas) locus, and 13 floral traits were significantly different in fas mutants. The phenotypic variability described in this study could help breeders select for more fertile flowers and assist reproductive biologists in linking genes to flower development.