Genetic Variance Estimates for Maize Yield, Grain Moisture, and Stalk Lodging for Doubled-Haploid and Conventional Selfed-Line Hybrids.

Ronald P Mowers,David J Foster

doi:10.3390/plants9020138

Abstract

An experiment was conducted to compare estimated genetic variance for maize doubled haploid (DH) with conventional twice-selfed (S2)-line hybrids. Starting with a 4-parent population, at least 160 lines were derived using both of these methods and crossed with two inbred testers. For both inbred testers, maize hybrid grain yield and stalk lodging had higher estimated genetic variances for DH than for S2. For one of the testers, estimated grain moisture genetic variance was higher for DH, but not for the other. The DH hybrid yield distributions on both testers were flatter and had more entries in tails compared with S2 distributions. With complete homozygosity of DH lines and the subsequent increased genetic variance among lines, the expected response to yield selection is higher for DH than for S2 line hybrids.

Highlights

IntroductionImprovement Center) commonly use doubled haploid (DH) lines to cross with inbred testers to form maize (Zea mays, L.) hybrids for testing and selection [1,2,3,4,5]
Seed companies and other organizations such as CIMMYT (International Maize and WheatImprovement Center) commonly use doubled haploid (DH) lines to cross with inbred testers to form maize (Zea mays, L.) hybrids for testing and selection [1,2,3,4,5]
Correlation of L/line with U/line hybrids was done to indicate consistency of the line performance over the two testers: correlation 1 indicating the exact same spacing and ordering of lines for both testers and correlation 0 indicating a random ordering for the testers. This experiment was designed to compare the performance of maize hybrids made from DH lines with hybrids using conventional S2-lines

Summary

Introduction

Improvement Center) commonly use doubled haploid (DH) lines to cross with inbred testers to form maize (Zea mays, L.) hybrids for testing and selection [1,2,3,4,5]. Geiger and Gordillo [2] cite advantages for DH lines, including complete homozygosity with the maximum genetic variance between lines for hybrid testcross performance, reduced breeding cycle time, increased efficiency of molecular marker applications [3,4], and other efficiencies. DH lines rather than some variance left within lines, as is the case with those derived by selfing [6,7]. In the experiment reported here, we compare the genetic variance between DH-line hybrids with that between conventional S2-line hybrids (derived by selfing twice from a parent population) for empirical evidence on whether there is a difference.

Methods

Results

Conclusion