Abstract:

【Objective】 The QTLs/genes related to stem growth of wheat which are expressed at different stages from jointing to flowering stage were detected. QTLs/genes expression on stem growth were studied to detect the number and genetic effects of QTLs/genes in different development stages, then to attain more genetic information of regulating plant height. 【Method】 Conditional and unconditional QTLs for plant height were studied using a doubled haploid (DH) population with 168 progeny lines, derived from a cross between two elite Chinese wheat cultivars Huapei 3×Yumai 57. Plant height was evaluated at 6 different stages (from jointing stage to flowering period), in different environments in 2008 and 2009 cropping seasons. QTL analyses were performed using a mixed linear model approach and a linkage map consisting of 323 marker loci was used to search QTLs for plant height. 【Result】 A total of 18 unconditional QTLs and 10 conditional QTLs were detected. Among the 18 unconditional QTLs, Qph5D-1 was persistently expressed at 4 stages. Qph4D-1 was persistently expressed at 3 stages. Among the 10 conditional QTLs, Qph5D-1 explained 30.1% of phenotypic variations. Qph4B was detected during 1st to 8th May, explained 20.3% of phenotypic variations. 【Conclusion】 The number and the expression of QTLs have a great change in the development of plant height, which suggest that the QTLs express depending on different developmental stages. The information obtained in this study should be useful for manipulating the QTLs by marker assisted selection (MAS) in wheat dwarf breeding programs.

Key words: wheat (Triticum aestivum L.), doubled haploid population, plant height, QTL mapping for developmental behavior