Abstract

HERNANDEZ-GOMEZ, J. A.; MIRANDA-COLIN, S.  and  PENA-LOMELI, A.. Natural outcrossing of chia (Salvia hispanica L.). Rev. Chapingo Ser.Hortic [online]. 2008, vol.14, n.3, pp.331-337. ISSN 2007-4034.

Mexico has the largest genetic diversity of chia (Salvia hispanica L.). Recently, chia seed derivates have attracted commercial attention. However, too little is known about its breeding system to define a genetic improvement strategy and to preserve its germplasm. In this study, the percentage of natural outcrossing of S. hispanica was determined in Chapingo, Mexico. Flower color was used as the genetic marker, considering purple flowers dominant over white and blue flowers. Two cross-pollination plots were established in 1999. In the first plot, seeds of purple-flowered plants and white-flowered plants of a cultivated genotype from Jalisco were sown alternately in each row; in the other, the same cultivar were sown alternately with seeds of purple-flowered cultivated plants and blue-flowered wild plants collected in Sinaloa. Determination of natural outcrossing rate was based on the percentage of purple-flowered plants in both the F₁ progeny of white-flowered cultivated plants and of blue-flowered wild plants. Outcrossing was more frequent in the cultivated genotype (22.17%) than in the wild genotype (1.51%), which might indicate that the breeding system was modified under cultivation. Since there was no reproductive isolation, the cultivated and wild genotypes should be considered subspecies or races of S. hispanica. The resulting hybrids were vigorous, like the cultivated parent, and had dehiscent fruits, like the wild parent.

Keywords : Salvia hispanica L.; flower color; breeding system; intra-species hybrids.