关键词: QTL作图, PCR标记, 株高, 抽穗期, 产量和产量组成, 有利隐蔽等位基因, 二粒小麦

Abstract: The objective of the present study is to reveal and map quantitative trait loci(QTL) conferring agronomic traits in tetraploid wheat, Triticum dicoccoides. An F₂ mapping population with 150 individuals was developed by crossing T. dicoccoides accession Hermon H52 with T. durum cultivar Langdon. Two versions of PCR-based molecular framework maps were constructed each mainly comprising of codominant markers and the dominant markers in coupling phase. Total map size exceeded 3000 cM and covered the entire genome. The following 11 traits of agronomic importance were measured:Plant height(HT), heading date(HD), spike number/plant(SNP), spikelet number/spike(SLS), spike weight/plant(SWP), single spike weight(SSW), kernel number/plant(KNP), kernel number/spike(KNS), kernel number/spikelet(KNL), 100 grain weight(GWH) and grain yield/plant(YLD). A new computer program MultiQTL was used to conducted the single-QTL analysis. Forty-nine QTLs were revealed for the 11 traits ranging from two(HT) to seven(GWH) QTLs per trait. All the QTLs were proven significant at 5% or higher level by permutation test. Binomial test indicated that large number of QTLs were not detected by chance, and so were real. The QTLs were not randomly distributed among chromosomes and along chromosomes. Most of the QTLs clustered in six regions on four chromosomes. Twenty-three major QTLs(p<0.001) were identified for the 11 traits, and more than half(17) of them clustered in three regions on chromosomes 2A and 5A. Many of the QTLs were mapped to very small chromosomal segments of <5 cM. Some cryptic beneficial alleles were uncovered from T. dicoccoides. The present study confirms that T. dicoccoides is a valuable germplasm for wheat improvement, could accelerate the genetic analysis of wheat, and has laid a solid foundation for QTL introgression and cloning from T. dicoccoides.

Key words: QTL MAPPING, PCR-BASED MARKERS, PLANT HEIGHT, HEADING DATE, YIELD AND YIELD COMPONENTS, CRYPTIC BENEFICIAL ALLELE, TRITICUM DICOCCOIDES