Prevalence of viviparous germination as a function of seasonal conditions and seed phenotypic characteristics in the bottle gourd Lagenaria siceraria (Molina) Standley (Cucurbitaceae)

Selection for resistance to viviparous germination is an important step and one of the most effective strategies for solving the problem of vivipary in orthodox seed species. Vivipary generally occurs when mature fruits are exposed to rain. To understand the existing relationships between seed phenotypic characteristics, seasonal conditions and the prevalence of vivipary in Lagenaria siceraria, experiments were carried out under natural conditions during the short and long rainy seasons of 2014 and 2015. Three main conclusions were drawn from the results. Firstly, yellowish seeds with a soft seed coat without a cap and yellowish seeds with a soft seed coat with a thin cap were more susceptible to vivipary with prevalences of 37.64% and 29.75% respectively. The whitish seeds with a hard seed coat and no cap, the brown seeds with a hard seed coat and no cap, the yellowish seeds with a soft seed coat and a thick cap and the seeds with a soft seed coat and a brown cap did not show vivipary whatever the intensity of the rain preceding harvest. Secondly, although the prevalence of vivipary was affected by the interaction of phenotype and rainy seasons, it explained only 7.57% of the variation. Most of the variation in vivipary prevalence was related to seed phenotype (68.33%) indicating that seed phenotype is the main factor influencing vivipary prevalence in L. siceraria. Finally, vivipary prevalence was strongly and positively correlated with rainfall and humidity in viviparous genotypes, whereas non-viviparous genotypes were not affected by climatic parameters.