Abstract

LOPEZ-ESPANA, RG et al. Geographical diferentiation of wild pepper (Capsicum annuum L. var. glabriusculum) populations from northwestern Mexico. Phyton (B. Aires) [online]. 2016, vol.85, n.1, pp.131-141. ISSN 1851-5657.

Wild pepper (Capsicum annuum L. var. glabriusculum) is a valuable genetic resource for food and agriculture. The patterns of variation of 12 morphological traits of 17 populations of wild pepper collected across a latitudinal and climate gradients in northwestern Mexico were analyzed in a uniform greenhouse experiment. The morphological traits data were axamined by univariate and multivarite analysis. The relationship between phenotypic variation and latitude of population origen was tested using linear regression analysis. We found high variation within and among populations for most of the measured traits. Populations were clearly differentiated by univariate analysis of variance and principal component analysis. Because plants grew in a uniform environment, these results indicate that the differences among the populations were due to genetic differences among them. Plant height, number of fruits, fruit weight, number of seeds per fruit, number of seeds per plant showed a clinal pattern of variation across latitudinal gradients. Plants from northern populations were shorter, produced more fruits, fruits were heavier, more seeds per fruit and more seeds per plant than plants from southern populations. The variation pattern observed in these traits suggests adaptation to local climate conditions. The variation of the other traits (stem diameter, leaf length and width, number of branches, fruit length and width and seed weight) was not significantly related to latitude de origin. It is possible that the observed differentiation in these traits was the result of different regimens of selection (and nonclinal) in each population, or a consequence of genetic drift.

Keywords : Capsicum annuum; Genetic resource; Latitudinal gradient; Population differentiation; Genetic variation.

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