Interspecific hybridization between cultivated and wild species of genus Passiflora L.

Abstract

The genus Passiflora L. has about 80 species with edible fruits and desirable agronomic characteristics which can be transferred to commercial species for further breeding by artificial hybridization. The aim of this study is to determine the self-fertility (SF) and interspecific compatibility of six commercially cultivated species and six wild species as a resource for future breeding programs. Reciprocal interspecific pollinations were carried out involving twelve species for a total of 144 hybrids combinations. The test of SF showed that seven species display no more than 5 % of fruit set, indicating self-incompatibility (P. cincinnata, P. maliformis, P. caerulea, P. mucronata and P. vitifolia, P.alata and P. edulis f. flavicarpa). Percentage of formed fruits in a fruit set ranged from 2.1 to 60 % and results showed significant differences in the effectiveness of some species in crosses when acting as the female parent. The highest fruit set was obtained when the female parent was P. vitifolia, P. mucronata and P. edulis f. edulis and P. edulis f. flavicarpa ranging from 22.2 to 60 %. Regarding fruit production, 48.1 % of the successful crosses reached physiological maturity giving a total of 21 fruits with similar sizes and number of seeds, as compared to the ones obtained by natural pollination. Post-zygotic barriers were detected in 53.8 % of the crosses where a fruit was formed due to failure in seed endosperm development or low germination. The highest percentage of germination was obtained in crosses of P. mucronata × P. alata and P. edulis f. flavicarpa × P. vitifolia with 87.5 and 100 %, respectively. The finding of high compatibility of some hybrid combinations in this study is promising. However, the performance of F1 hybrids needs to be determined in field evaluations to assess the real potential for further breeding.