title: Epistasis together with partial dominance, over-dominance and QTL by environment interactions contribute to yield heterosis in upland cotton.
abstract: QTL mapping based on backcross and RIL populations suggests that epistasis together with partial dominance, over-dominance and their environmental interactions of QTLs play an important role in yield heterosis in upland cotton. A backcross population (BC) was constructed to explore the genetic basis of heterosis in upland cotton (Gossypium hirsutum L.). For yield and yield components, recombinant inbred line (RIL) and BC populations were evaluated simultaneously at three different locations. A total of 35 and 30 quantitative trait loci (QTLs) were detected based on the RILs and BC data, respectively. Six (16.7 %) additive QTLs, 19 (52.8 %) partial dominant QTLs and 11 (30.6 %) over-dominant QTLs were detected by single-locus analysis using composite interval mapping in BC population. QTLs detected for mid-parent heterosis (MPH) were mostly related to those detected in the BC population. No significant correlation was found between marker heterozygosity and performance. It indicated that heterozygosity was not always favorable for performance. Two-locus analysis revealed 46, 25 and 12 QTLs with main effects (M-QTLs), and 55, 63 and 33 QTLs involved in digenic interactions (E-QTLs) were detected for yield and yield components in RIL, BC and MPH, respectively. A large number of M-QTLs and E-QTLs showed QTL by environment interactions (QEs) in three environments. These results suggest that epistasis together with partial dominance, over-dominance and QEs all contribute to yield heterosis in upland cotton.
authors.affiliation: 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.
authors.forename: Lianguang
authors.initials: L
authors.lastname: Shang
authors.affiliation: 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.|The Key Laboratory of Tropical Fruit Biology of Ministry of Agriculture, The South Subtropical Crops Research Institutes, Chinese Academy of Tropical Agricultural Sciences, Zhanjiang, 524091, China.
authors.forename: Qingzhi
authors.initials: Q
authors.lastname: Liang
authors.affiliation: 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 Crop, Hubei Academy of Agricultural Sciences, Wuhan, 430064, Hubei, China.
authors.forename: Yumei
authors.initials: Y
authors.lastname: Wang
authors.affiliation: 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.
authors.forename: Yanpeng
authors.initials: Y
authors.lastname: Zhao
authors.affiliation: Institute of Cotton Research, Chinese Academy of Agricultural Sciences/State Key Laboratory of Cotton Biology, Anyang, 455000, Henan, China.
authors.forename: Kunbo
authors.initials: K
authors.lastname: Wang
authors.affiliation: 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. jinping_hua@cau.edu.cn.
authors.forename: Jinping
authors.initials: J
authors.lastname: Hua
mesh_terms: D003433:Crosses, Genetic; D004777:Environment; D004843:Epistasis, Genetic; D003368:Gossypium / Q000235:genetics*; D006823:Hybrid Vigor; D040641:Quantitative Trait Loci