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https://www.ias.ac.in/article/fulltext/jgen/091/03/0303-0312

wheat; grain protein content; yield; conditional QTL mapping.

Grain protein content in wheat (Triticum aestivum L.) is generally considered a highly heritable character that is negatively correlated with grain yield and yield-related traits. Quantitative trait loci (QTL) for protein content was mapped using data on protein content and protein content conditioned on the putatively interrelated traits to evaluate possible genetic interrelationships between protein content and yield, as well as yield-related traits. Phenotypic data were evaluated in a recombinant inbred line population with 302 lines derived from a cross between the Chinese cultivar Weimai 8 and Luohan 2. Inclusive composite interval mapping using IciMapping 3.0 was employed for mapping unconditional and conditional QTL with additives. A strong genetic relationship was found between protein content and grain yield, and yield-related traits. Unconditional QTL mapping analysis detected seven additive QTL for protein content, with additive effects ranging in absolute size from 0.1898% to 0.3407% protein content, jointly accounting for 43.45% of the trait variance. Conditional QTL mapping analysis indicated two QTL independent from yield, which can be used in marker-assisted selection for increasing yield without affecting grain protein content. Three additional QTL with minor effects were identified in the conditional mapping. Of the three QTLs, two were identified when protein content was conditioned on yield, which had pleiotropic effects on those two traits. Conditional QTL mapping can be used to dissect the genetic interrelationship between two traits at the individual QTL level for closely correlated traits. Further, conditional QTL mapping can reveal additional QTL with minor effects that are undetectable in unconditional mapping.

Lin Wang^{1 2} Fa Cui^{1 3} Jinping Wang² Li Jun^{1 4} Anming Ding^{1 5} Chunhua Zhao^{1 3} Xingfeng Li¹ Deshun Feng¹ Jurong Gao¹ Honggang Wang¹

1. State Key Laboratory of Crop Biology, Shandong Key Laboratory of Crop Biology, Taian Subcenter of National Wheat Improvement Center, College of Agronomy, Shandong Agricultural University, Taian 271018, People’s Republic of China
2. Jining Municipal Academy of Agricultural Sciences, Ji’ning 272031, Shandong, People’s Republic of China
3. Center for Agricultural Resources Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Shijiazhuang, 050021, Hebei, People’s Republic of China
4. Tianxing Biotechnology, Handian Industrial Zone, 256200 Zouping, Shandong, People’s Republic of China
5. Tobacco Research Institute, Chinese Academy of Agricultural Sciences, Qingdao 266101, People’s Republic of China

Manuscript received

7 March 2012

Manuscript revised

10 July 2012

Accepted

25 July 2012

Early published

5 December 2012