INTERPOPULATION HETEROSIS FOR AGROMORPHOLOGY AND CAPSAICINOIDS IN NATIVE PEPPERS FROM OAXACA

Abstract

Native populations of pepper (Capsicum annuum L.) are highly heterogeneous and divergent, and some of them may be used as parents to formulate breeding strategies, that explore and exploit maximum heterosis from their genetic divergences. In this work, inter-population heterosis on agro-morphological traits and capsaicinoids was evaluated on interpopulation hybrids of native pepper from different geographic origin. Eight progenitors and nine hybrids were evaluated agro-morphologically and by gas chromatography (GC) for determination of capsaicin (CAP) and dihydrocapsaicin (DH) content in fruit. Significant differences (P < 0.01) were determined among progenitors and hybrids in days to flowering, number of ripening fruits, plant height, weight and number of fruits per plant, and fruit length and width. Positive and negative heterosis compared to mid-parent and best progenitor were calculated over all phenological traits, and positive heterosis respect to mid-parent was estimated for number and weight of fruits per plant, but in this case it was associated with lower fruit length. The populations of Solterito type from Oaxaca (C-14) and Bolita from Chiapas (C-18) had the highest content of CAP (> 66 μg mL^-1) and DH (> 96 μg mL^-1); in contrast, the chile de Agua populations had the lowest CAP and DH content, with 44 and 42 μg mL^-1, respectively. In the interpopulation hybrids, the average in capsaicinoid content was less than in their progenitors; consequently, there were no significant differences in heterosis compared to their parents; except when C-14 was a progenitor, a morphotype with the highest content of CAP and DH. Results indicate that is possible to take advantage of the heterosis generated from crossing of divergent populations in fruit morphology and different content of capsaicinoids and geographic origin.