Fruit and seed morphological divergence between wild and cultivated enset (Ensete ventricosum [Welw.] Cheesman)

Abstract

Enset is a single-stemmed plant; i.e., non-suckering naturally both in wild and cultivated states. There are great differences in their life cycles between the wild and cultivated populations of enset. Wild enset reproduce naturally via seeds. As cultivated enset is usually harvested before or shortly after flowering, the development of flowers and fruits is rarely encountered in cultivation. As a result, cultivated enset is propagated vegetatively, with adventitious buds sprouting from the corm after the removal of the apical meristem. In vegetatively propagated crops, the loss of sexual reproduction capacity has been recognized as a domestication syndrome. The present study was performed to determine the pattern of fruit and seed variation between and within wild and cultivated populations, by measuring morphological differences in fruit and seed traits (number of hands per bunch, number of fruit per mid-hand, mean fruit weight, fruit length, fruit circumference, seed number per fruit, seed weight and seed diameter) in wild and cultivated plants. Results of pairwise PERMANOVA comparisons showed significant difference between wild and domesticated enset in terms of their fruit and seed morphological characters. Among the traits studied, average fruit weight, fruit length, fruit circumference, and number of seeds per fruit were the traits that differed most between cultivated and wild. These characters were significantly greater in the wild population than in cultivated. We suggest that these traits could define the domestication syndrome of this plant. Despite significant divergences between wild and cultivated ensets, some cultivated accessions, were certainly domesticated landrace are placed together with wild accessions in PCA biplot. Our results point to the possibility of complex evolutionary dynamics of both cultivated and wild forms, and gave an insight that there is huge potential to improve this crop through hybridization and clonal selection methods. Furthermore, the present results provide useful indications on how to act for more rational planning in reproductive material management and genetic resource conservation strategies.