Seed aging decreases the quality and vigor of crop seeds,thereby causing substantial agricultural and economic losses in crops.To identify genetic differences in seed aging between homozygotes and heterozygotes in maize,the seeds of a set of recombinant inbred lines(RILs) and an immortalized F_2(IF_2) population were subjected to artificial aging treatments for 0,2,3,and 4 days under 45℃ and 85%relative humidity and seed vigor was then evaluated in a field experiment.Seed vigor of all entries tested decreased sharply with longer aging treatment and seed vigor decreased more slowly in heterozygotes than in homozygotes.Forty-nine QTL were detected for four measured seed vigor traits in the RIL(28QTL) and IF_2(21 QTL) populations.Only one QTL,qGP5,was detected in both populations,indicating that the genes involved in anti-aging mechanisms differed between inbred lines and hybrids.Several QTL were identified to be responsible for multiple seed vigor traits simultaneously in the RIL and IF_2 populations under artificial aging conditions.These QTL may include major genes for seed vigor or seed aging.QTL qVI4 b and qGE3 a detected in the RIL population coincided with genes ZmLOX1 and ZmPLD1 in the same respective chromosomal regions.These QTL would be useful for screening for anti-aging genes in maize breeding.
Bin WangZhanhui ZhangZhiyuan FuZonghua LiuYanmin HuJihua Tang
Heterosis is an important biological phenomenon, and it has been used to increase grain yield, quality and resistance to abiotic and biotic stresses in many crops. However, the genetic mechanism of heterosis remains unclear up to now. In this study, a set of 184 chromosome segment substitution lines （CSSLs） population, which derived from two inbred lines Ix9801 （the recurrent parent） and Chang 72 （the donor parent）, were used as basal material to construct two test populations with the inbred lines Zheng 58 and Xun 9058. The two test populations were evaluated in two locations over two years, and the heterotic loci for plant height and ear height were identified by comparing the performance of each test hybrid with the corresponding CK at P〈0.05 significant level using one-way ANOVA analysis and Duncan＇s multiple comparisons. There were 24 and 29 different heterotic loci （HL） identified for plant height and ear height in the two populations at two locations over two years. Three HL （hlPH4a, hlPH7c, hlPHlb） for plant height and three （hlEHld, hlEH6b, hlEHlb） for ear height were identified in the CSSLs×Zheng 58 and CSSLs×Xun 9058 populations as contributing highly to heterosis performance of plant height and ear height across four environments. Among the 29 HL identified for ear height, 12 HL （41.4%） shared the same chromosomal region associated with the HL （50.0%） identified for plant height in the same test population and environment.
WANG Hong-qiuZHANG Xiang-geYANG Hui-liCHEN Yong-qiangYUAN LiangLI Wei-huaLIU Zong-huaTANG Ji-huaKANG Ding-ming
