Seleção genética para precocidade em uma população segregante demilho (Zea mays L.)
Due to the set of changes and factors corn crop has been subjected in the last fewdecades, earliness became one of the major characters for addition of geneticvalue and adaptability to currently cultivated corn hybrids. Thus, selection ofcharacters related to earliness has been of large interest to corn breedingprograms. The aim of this work was to estimate genetic parameters related toearliness in a tropical corn population adapted to the central region of Brazil. Inthis study were evaluated 188 F4 testcrosses in an expanded statistical blockdesign at six locations and plant density of 70,000pl ha-1. Significant differenceswere detected between the testcrosses (G), Location (L) and GxL interaction. Theheritability coefficient for these testcrosses varied from 35.25% for stalk and rootlodging (TQA) and 68.91% for pollen shed (FM). Genetic gain estimates showedthat it is possible to improve each of these characters individually, via directselection. However, estimates of indirect effect showed that correlated changes, ingeneral, are unfavorable. The estimated genetic parameters suggest thatutilization of selection indexes that, besides grain yield, include characters such asgrain moisture, pollen shed, silk, stalk and root lodging to select the testcrosses,under normal development condition the crop, can lead to the development ofhybrids with high grain yield and earliness, simultaneously.
Advisor:Fernando César Juliatti; Renzo Garcia Von Pinho; Heyder Diniz Silva
School:Universidade Federal de Uberlândia
Source Type:Master's Thesis
Date of Publication:06/30/2008