Genetic Evaluation of Exotic Chromatins from Two Obsolete Interspecific Introgression Lines of Upland Cotton for Fiber Quality Improvement

Abstract

Interspecific introgression lines are important resources for plant breeders to access novel alleles from exotic germplasm. The Pee Dee breeding program developed several extra‐long staple “Sealand” germplasm lines that presumably contain sea island cotton (Gossypium barbadense L.) chromatin introgressed into upland cotton (Gossypium hirsutum L.). The objectives of this study were to identify the G. barbadense chromatins in the Sealand lines, 542 and 883, and evaluate their effects on fiber quality. A total of 31 putative G. barbadense chromatins were detected, including 12 segments on seven chromosomes that were unique to Sealand 542 and 10 segments on five chromosomes that were unique to Sealand 883, and the remaining nine segments were common to both the Sealand lines. Sealand 542 and 883 mapping populations were created to identified 28 quantitative trait locus (QTL) regions associated with fiber quality traits, including six for elongation, four for fineness, five for short fiber content, five for strength, three for length, and five for fiber uniformity. At least 13 QTLs were detected on the G. barbadense introgressed chromosomal segments. Favorable alleles for 17 QTLs were contributed by the Sealand lines, and the genetic effects of five loci were stably expressed across environment and generation. Stable expression of G. barbadense fiber quality alleles in the Sealand lines and the absence of these alleles in upland germplasm make these introgression lines a valuable resource for fiber quality improvement. In particular, marker‐assisted introgression of the qFL‐Chr25 locus from Sealand 883 should result in improved fiber length, whereas that of qMIC‐Chr24 from Sealand 542 should result in finer fiber.

Registration of eight upland cotton (Gossypium hirsutum L.) germplasm lines with qFL‐Chr.25, a fiber‐length QTL introgressed from Gossypium barbadense

“…SL883 was crossed with four G. hirsutum parents, chosen for their representation of the four major cotton growing regions in the United States: Acala SJ‐4 (C6TE/NMB3080), representing the desert Southwest; PMHS26 (Acala SJ‐4/5B9‐184), from the Texas High Plains; DP50 (DP 16//DP Smoothleaf/DP 45/3/DES56), of the Mississippi Delta region; and GA089 (PD 94042/AP 7126), an unreleased breeding line from the University of Georgia representing the southeastern United States. Initiated in 2006 at Tifton, GA, these four crosses were made as a fiber quality QTL mapping project (Kumar et al., ). F 1 plants were grown in the greenhouse over the winter, and F 2 seed was planted in the summer of 2007 at the University of Georgia, Coastal Plain Experiment Station's Gibbs Research Farm in Tifton.…”

“…The Sealand germplasm lines are essentially G. hirsutum genotypes with exceptional FL and fiber bundle strength (STR) but mediocre agronomic performance. One of these lines, SL883, was discovered to be carrying introgressed segments from G. barbadense harboring several quantitative trait loci (QTL) for fiber quality traits (Kumar et al., ). One QTL in particular, qFL‐Chr.25 , had a large effect in the original biparental mapping population and when subsequently validated in four different cultivar genetic backgrounds, explained from 4.4 to 61.4% of the variation in FL (Kumar et al., ).…”

“…One of these lines, SL883, was discovered to be carrying introgressed segments from G. barbadense harboring several quantitative trait loci (QTL) for fiber quality traits (Kumar et al., ). One QTL in particular, qFL‐Chr.25 , had a large effect in the original biparental mapping population and when subsequently validated in four different cultivar genetic backgrounds, explained from 4.4 to 61.4% of the variation in FL (Kumar et al., ). The four genetic backgrounds used in the experiment were chosen to represent the four major cotton growing regions within the United States.…”

“…A large number of fiber quality QTLs have been mapped in interspecific populations or from introgression lines derived from G. barbadense (Chee & Campbell, ; Chee et al., ); however, few of these have been validated and fewer still have been incorporated into adapted germplasm. qFL‐Chr.25 demonstrated a modest yet significant effect when deployed in the genetic background of ‘Acala SJ‐4’ (PI 529538), ‘Deltapine 50’ (DP50) (PVP 8400154; PI 529566), ‘Paymaster HS 26’ (PMHS26) (PVP 8600087; PI 606814), and GA 2004089 (GA089) (Brown et al., ; Kumar et al., ). The group of lines discussed here for public release represent the most desirable genotypes from an experiment designed to quantify the effect of qFL‐Chr.25 by observing highly related BSLs that differed very little except for the presence or absence of the QTL region.…”

Yield performance and fiber quality of Pima cotton grown in the southeast United States

“…On a global scale, Pima cotton only accounts for approximately 3 to 5% of the total cotton production, whereas upland cotton accounts for the majority of the remainder (Fang, 2018). William Elliot was the first person to cultivate G. barbadense in the United Crop Science (Kumar et al, 2019). Today, upland cotton remains the only species of cotton produced commercially in the southeast United States, accounting for approximately $1.7 billion USD in 2019, with 1.2 million ha planted across Alabama, Georgia, Florida, South Carolina, North Carolina, and Virginia (USDA-National Agricultural Statistics Service, 2020).…”