GRAIN AND TORTILLAS QUALITY OF NATIVE MAIZE LANDRACES AND THEIR BACKCROSSES

Abstract

In this research we determined the physical and chemical properties of native maize landraces and their backcrosses, as well as the quality of the nixtamal, dough and tortilla in the ten native landraces most used in this process in México. Forty native maize landraces (L) and 70 backcrosses (BC₁F₃) were analyzed. Seventy-five percent of backcrosses increased the grain yield by 30 %. Tuxpeño Norteño, Pepitilla and Celaya reached the highest yields. The hectolitric weight was increased by 60% in the backcrosses, which was negatively correlated to the flotation index (r = - 0.74**) and to the proportion of the floury endosperm (r = - 0.45**). The maize landraces had higher percentages of pedicel, germ and floury endosperm than the backcrosses. Bolita (BC₁F₃) had the lowest percentage of pedicel (0.86%), followed by the landraces Elotes Occidentales, Blando and Dulcillo (0.92%). These landraces and their respective backcrosses had the lowest proportion of pericarp (4.3%). Bolita (12.2%), Zapalote Grande (12.4%) and Dulce 9 (14.4%) had the largest proportion of germ. Dulce 9 also presented the highest oil content (7.6%). In the nixtamalization, maizes with the highest flotation index had also the highest nixtamal moisture (r = 0.42**). Bolita (BC₁F₃) masa had the lowest values of maximum viscosity (190 UB), final viscosity (290 UB) and texture (293 g_f), which allowed to elaborate the best tortillas; their hardiness was 303 g_f. The genetic breeding modified the physical grain characteristics and the quality of tortillas.