QTL Mapping Of Grain Test Weight Related Traits In Maize

As the most important field crops, maize was known as the "King of forage", the high yield and high quality have been the main breeding goal for breeders. The grain length (GL), grain width (GW), grain thickness (GT),100-grain weight (HGW) are part of the maize yield traits, and also directly affect the size of test weight (TW). We can dig deeper and more efficiently the gene of controlling the grain TW-related by QTL mapping for grain-related traits of maize to laying the foundation for molecular marker assisted selection breeding of improving test weight of maize. This study used inbred lines 8048 and LH8012 group with F2 population for location group, and constructe genetic linkage map with SSR markers, make QTL mapping for the GL, GW, GT, HGW and TW of the five traits, and analysis genetic-related and heritability of traits. The main results as follows:1. In this experiment, the two parents were detected DNA polymorphic with 1058 SSR markers.151 polymorphic markers were screened. A total length of genetic map that constructed by SSR markers was 1480.94cM. Chromosome 1 had 30 polymorphic markers and the genetic distance was maximum for 332.69cM, and other chromosome marker number respectively for 9,16,18,22,11,13,9,10,13. The genetic distance for 92.1 cM, 216.29 cM,216.35 cM,231.45 cM,128.55 cM,93.99 cM,124.04 cM,7.634 cM,185.29 cM.2. The phenotypic data of two environments analysis showed:The GL and GT, HGW were significantly positive correlation, the GW and HGW showed significantly positive correlation in grain TW-related traits of maize. The results of the heritability analysis of GL, GW, GT, HGW and TW show:these five traits heritability were 78.17%,79.08%, 77.99%,74.80%,80.38%. Heritability of all traits were relatively close.3. We used mixed-model based composite interval mapping (MCIM) in a single environment and two joint environments QTL mapping by NETwork2.1 mapping software. Obtained 33 QTL of controlled grain TW-related traits, these QTL were mapped on chromosome 1,3,4,5,6,7,8 and 10, there were 16 QTL that the contribution rate more than 10%, got 3 consistency QTL in 16 QTL, they were controlled GW(qCGW4), GT (qCGT1), and TW (qCTW10) respectively.According to the results, it could lay the foundation for next the fine mapping of grain TW-related of maize and has a certain reference value for molecular marker-assisted selection breeding of improving grain test weight of maize.