QTL mapping of agronomic and economic traits for four F2 populations of upland cotton

Hongge Li,Baojun Chen,Liru Wang,Shoupu He,Baoyin Pang,Yinhua Jia,Zhaoe Pan,Xiaoli Geng,Xiongming Du

doi:10.1186/s42397-020-00076-y

Abstract

BackgroundUpland cotton (Gossypium hirsutum) accounts for more than 90% of the annual world cotton output because of its high yield potential. However, yield and fiber quality traits often show negative correlations. We constructed four F2 populations of upland cotton, using two normal lines (4133B and SGK9708) with high yield potential but moderate fiber quality and two introgression lines (Suyuan04–3 and J02–247) with superior fiber quality, and used them to investigate the genetic basis underlying complex traits such as yield and fiber quality in upland cotton. We also phenotyped eight agronomic and economic traits and mapped quantitative trait loci (QTLs).ResultsExtensive phenotype variations and transgressive segregation were found across the segregation populations. We constructed four genetic maps of 585.97 centiMorgan (cM), 752.45 cM, 752.45 cM, and 1 163.66 cM, one for each of the four F2 populations. Fifty QTLs were identified across the four populations (7 for plant height, 27 for fiber quality and 16 for yield). The same QTLs were identified in different populations, including qBW4 and qBW2, which were linked to a common simple sequence repeat (SSR) marker, NAU1255. A QTL cluster containing eight QTLs for six different traits was characterized on linkage group 9 of the 4133B × Suyuan04–3 population.ConclusionsThese findings will provide insights into the genetic basis of simultaneous improvement of yield and fiber quality in upland cotton breeding.

Highlights

SGK9708 was derived from CCRI41, which is a widely planted cultivar with wide adaptability; 4133B was derived from the hybridization of SGK9708 and the offspring of Gan4104 and CZA (70)33 and has high combining ability; Suyuan04–3 was derived from the distant hybridization of [83–811 × (86–1 × G.armourianum)]; and J02–247 was derived from the cross of Suyin45 × Sukang310, and has large cotton bolls as well as superior fiber length and strength
Transgressive segregation means that the phenotypic values of some individuals were better than those of the superior parent or worse than those of the inferior parent (Reyes 2019)
Among fiber length (FL), fiber strength (FS), fiber length uniformity (FU), fiber elongation (FE), and MIC, the coefficient of variation (CV) value was lowest for FU (1.59–2.61%) and highest for MIC (13.87– 22%)

Summary

Introduction

Upland cotton (Gossypium hirsutum) accounts for more than 90% of the annual world cotton output because of its high yield potential. We constructed four F2 populations of upland cotton, using two normal lines (4133B and SGK9708) with high yield potential but moderate fiber quality and two introgression lines (Suyuan and J02–247) with superior fiber quality, and used them to investigate the genetic basis underlying complex traits such as yield and fiber quality in upland cotton. Upland cotton (Gossypium hirsutum) accounts for more than 90% of the global cotton production because of its high yield potential and broad adaptability, but it has moderate fiber quality, whereas G. barbadense produces exceptionally fine-quality fibers, but with lower fiber yield (Cai et al 2014; Hu et al 2019). Most agronomic and economic traits, such as yield and fiber quality, are quantitative traits that are controlled by multiple loci/genes. Dissecting the genetic basis of yield and fiber quality is essential for simultaneous improvement of yield and fiber quality

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Discussion

Conclusion