Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: April 13, 2004
Publication Date: May 6, 2005
Citation: Meredith Jr, W.R. 2005. Minimum number of genes controlling cotton fiber strength in a backcross population. Crop Science. 45:1114-1119. Interpretive Summary: The US cotton industry greatly needs higher fiber strength in order to efficiently process fiber with modern high speed textile equipment. A genetic analysis was made on a cotton population that segregated for high fiber bundle strength. The source of the bundle strength was FTA 263-20, which was released by ARS at Florence, SC. FTA 263-20 obtained its higher fiber strength from introgressions of Gossypium barbadense, G. arboretum, and G. thurberi. FTA 263-20 was first crossed to Delta Pine 16 and then backcrossed into Delta Pine 16 nectariless five times. This was followed by six backcrosses into Delta Pine 90ne. The nectariless background was used in this research so that progeny developed in the program would have resistance to four major cotton insect pests. The analysis estimated that an increase in fiber strength of 10% was controlled by no more than two major genes. A germplasm release to the public is being processed in order that cotton breeders may have access to this germplasm to broaden their genetic base for cotton improvement.
Technical Abstract: US textile mills require strong cotton fiber (Gossypium hirsutum L.) for high-speed modern textile operations. The primary objective of this study was to determine the inheritance of strength descending from FTA 263-20 (FTA). FTA was developed by introgression into G. hirsutum L. from G. arboreum, G. thurberii, and G. barbadense. Five backcrosses (BCs) into DP 16 followed by six BCs into DP 90ne were made. In 2001, three sets of 64 BC6 F2:F3 progenies were evaluated for strength. Significant variability for F2:F3 strength (F = 2.79), yield, three yield components, and four other fiber traits were detected. From a three replication test, strength gene number(s) estimates ranged from 1.10 to 1.29, and combined over sets was 1.23 genes. Average strength for the three BC5 parents was 10.3% greater than DP 90ne's and its yield was 16.9% less. Strength was highly correlated with lint percentage, boll weight, seed weight, and 2.5% span length. Correlated traits gene number ranged from 0.02 for micronaire to 1.04 for yield. A separate study involving the BC5 parents, DP 90 and DP 90ne was used to determine the major physical components of strength. Fineness and individual fiber strength had no effect. Short fiber content significantly impacted strength as the three BC5 parents average short fiber was 6.7 versus 8.7% for the DP 90s. The BC5 parents average strength was 11% higher, 240 vs. 219 kNmkg-1, and its yield was 9.0% lower than DP 90ne. Probably a single major gene or closely linked cluster of genes resulted in increased fiber strength.