Shang Lianguang, Wang Yumei, Cai Shihu, Ma Lingling, Liu Fang, Chen Zhiwen, Su Ying, Wang Kunbo, Hua Jinping
Department of Plant Genetics and Breeding/Key Laboratory of Crop Heterosis and Utilization of Ministry of Education/Beijing Key Laboratory of Crop Genetic Improvement, China Agricultural University, Beijing 100193, China.
Research Institute of Cash Crops, Hubei Academy of Agricultural Sciences, Wuhan 430064, Hubei, China.
Sci Rep. 2016 Oct 17;6:35515. doi: 10.1038/srep35515.
Yield is an important breeding target. As important yield components, boll number per plant (BNP) shows dynamic character and strong heterosis in Upland cotton. However, the genetic basis underlying the dynamic heterosis is poorly understood. In this study, we conducted dynamic quantitative trait loci (QTL) analysis for BNP and heterosis at multiple developmental stages and environments using two recombinant inbred lines (RILs) and two corresponding backcross populations. By the single-locus analysis, 23 QTLs were identified at final maturity, while 99 QTLs were identified across other three developmental stages. A total of 48 conditional QTLs for BNP were identified for the adjacent stages. QTLs detected at later stage mainly existed in the partial dominance to dominance range and QTLs identified at early stage mostly showed effects with the dominance to overdominance range during plant development. By two-locus analysis, we observe that epistasis played an important role not only in the variation of the performance of the RIL population but also in the expression of heterosis in backcross population. Taken together, the present study reveals that the genetic basis of heterosis is dynamic and complicated, and it is involved in dynamic dominance effect, epistasis and QTL by environmental interactions.
产量是一个重要的育种目标。作为重要的产量构成因素，陆地棉单株铃数（BNP）表现出动态特性和较强的杂种优势。然而，动态杂种优势背后的遗传基础却知之甚少。在本研究中，我们使用两个重组自交系（RIL）和两个相应的回交群体，在多个发育阶段和环境下对BNP和杂种优势进行了动态数量性状位点（QTL）分析。通过单基因座分析，在最终成熟时鉴定出23个QTL，而在其他三个发育阶段共鉴定出99个QTL。共鉴定出48个相邻阶段BNP的条件QTL。在植物发育过程中，后期检测到的QTL主要存在于部分显性到显性范围内，而早期鉴定出的QTL大多表现出从显性到超显性范围的效应。通过双基因座分析，我们观察到上位性不仅在RIL群体表现的变异中起重要作用，而且在回交群体杂种优势的表达中也起重要作用。综上所述，本研究表明杂种优势的遗传基础是动态且复杂的，它涉及动态显性效应、上位性以及QTL与环境的相互作用。
