Bases Genéticas de la determinación del peso de grano en una población de RILs (B73 x Mo17) de maíz

SANTIAGO ALVAREZ PRADO; LUCAS BORRÁS; CÉSAR GABRIEL LÓPEZ; BRENDA LAURA GAMBÍN; MARÍA ELENA OTEGUI

Congreso; IX Congreso Nacional de Maíz y I Simposio Nacional de Sorgo; 2010

Maize yield is a function of the number of harvested kernels per unit land area and the individual kernel weight. Kernel weight is usually analyzed considering the rate of kernel growth and the total duration of grain filling, and kernel water relations are useful to describe this pattern. Final kernel weight, kernel growth rate, duration of grain filling and maximum water content differ markedly among commercial hybrids and public or elite lines. However, little is known about the genetic bases controlling these traits. Our objectives were: i) to phenotypically characterize final kernel weight, rate, duration and maximum water content in a RIL population, and ii) to establish the genetic bases behind these traits through QTL detection. We characterized 259 recombinant inbred lines (RILs) from the IBM mapping population (B73 x Mo17) during 2009/2010 in Zavalla, Argentina. 400 molecular markers were used for linkage map development. All traits showed significant differences within the population (p<0.001). Final kernel weight ranged from 165 to 338 mg kernel-1, kernel growth rate varied from 0,23 to 0,59 mg ºCd-1 kernel-1, grain-filling duration ranged from 761 to 1151 ºCd and maximum water content from 132 to 314 mg kernel-1. We detected 6 QTLs for kernel weight, 7 QTLs for kernel growth rate, 6 for grain filling duration and 9 for maximum water content. Several coincidences were found with QTLs already reported. We expected QTLs for kernel growth rate and grain-filling duration to be differently localized, but several QTLs were similar for both traits. We also expected some QTLs for maximum water content, kernel growth rate and kernel weight to be similar, as these traits are physiologically correlated, but this was not the case in the present study.