CALIDAD PROTEICA EN SEGREGANTES DE CRUZAS DE DOS FUENTES DEL GEN OPACO-2 CON VARIEDADES ANDINAS DE MAÍZ.

Fourteen F2 segregating families, from crosses among Peruvian racial composites of maize with two Andean pools formed with a considerable proportion of Andean germplasm, homocigous for the gene opaque -- 2, were selfcrossed. The ears were harvested and selected for their similarities with the racial composites. Ten ears of each family were evaluated by their morphological characteristics: ear length, ear width, cob diameter, rachis diameter, grain depth, and ear row number. Ten seeds representative of each ear were evaluated for their pericarp, aleurone and endosperm colors. Comparisons of the morphological parameters were done between the segregating families and the Peruvian racial composites. In order to check the presence of the opaque 2 gene that improve the quality protein maize by reducing the levels of zein in the kernel, five grains of each ear were analyzed chemically. A rapid turbidimetric analysis for zein based on Paulis et al. (1974) method was carried out. The opaque variety PMS 267 was used as check. The Andean pools 1 and 2 showed to be good progenitors to incorporate the opaque-2 gene, without modifying the Andean characters of the ears in the offspring population evaluated. In all the racial composites, the opaque-2 gene that increases the quantity of two essential amino acids in the grain was introduced. Neither the grain type nor the color was modified. The method of selection of similar ears to the Peruvian progenitor in the first generations of self crosses is a good method, being faster than the backcross method in order to incorporate this gene and to maintain it in the offspring populations. In that way it is possible to maintain the opaque-2 gene in high frequency in the Peruvian maize diversity. [ABSTRACT FROM AUTHOR]