Stability and transferability assessment of the cotton fiber strength QTL qFS-c7-1 on chromosome A07

Authors: Fang, David; Zeng, Linghe; Thyssen, Gregory; Delhom, Christopher - Chris; Bechere, Efrem; JONES, DON - Cotton, Inc; Li, Ping

Submitted to: The Crop Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/31/2020
Publication Date: 1/28/2021
Citation: Fang, D.D., Zeng, L., Thyssen, G.N., Delhom, C.D., Bechere, E., Jones, D.C., Li, P. 2021. Stability and transferability assessment of the cotton fiber strength QTL qFS-c7-1 on chromosome A07. The Crop Journal. 9(2):380-386. https://doi.org/10.1016/j.cj.2020.06.016.
DOI: https://doi.org/10.1016/j.cj.2020.06.016

Interpretive Summary: As a new technology, marker assisted selection (MAS) can significantly enhance breeding efficiency. However, DNA markers associated with an agronomic trait especially quantitative trait such as fiber quality need to be validated in different environments or populations before being fully implemented in breeding. In this research, we made ten new populations to assess the stability and transferability of a fiber strength quantitative trait locus (QTL) on chromosome A07. A total of 2801 F2 plants were grown and their fiber quality traits were measured. All F2 plants were genotyped using DNA markers associated with the A07 strength QTL. We also selected a subset of F3 seeds from two populations, and grew F3 progeny plots to further evaluate the stability of the QTL. Our results showed that the strength QTL peak is around the 70-72 Mb region on chromosome A07. This QTL had a major effect on fiber strength, however, no effect on elongation was observed. Its effect on micronaire (MIC), short fiber content (SFC), length (UHM) and uniformity (UI) varied between populations. The effect of this QTL was stable in the populations analyzed, and in different generations of the same population. Selection based on the DNA markers associated with this QTL could improve fiber strength and likely MIC, SFC, UHM and UI, depending on the populations. The DNA markers reported herein will assist selecting superior fiber traits especially strength in breeding, with a recommendation that the parental cotton lines should be analyzed using DNA markers within the QTL peak area before fully implementing marker assisted selection in a cotton breeding program.

Technical Abstract: Previously we identified a major cotton fiber strength QTL on chromosome A07 using a multi-parent advanced generation intercross (MAGIC) population. We made ten new populations to assess the stability and transferability of this QTL, and its utility in cotton breeding. These populations were developed from crosses between MAGIC recombinant inbred lines, or between cotton varieties that are different from the MAGIC parents. A total of 2801 F2 plants were grown and their fiber quality traits were measured. All F2 plants were genotyped using DNA markers associated with the A07 strength QTL. We also selected a subset of F3 seeds from two populations, and grew F3 progeny plots to further evaluate the stability of the QTL. Our results showed that the strength QTL peak is around the 70-72 Mb region on chromosome A07. This QTL had a major effect on fiber strength explaining 21.9% phenotypic variance, however, no effect on elongation was observed. Its effect on micronaire (MIC), short fiber content (SFC), length (UHM) and uniformity (UI) varied between populations. The effect of this QTL was stable in the populations analyzed, and in different generations of the same population. Selection based on the DNA markers associated with this QTL could improve fiber strength and likely MIC, SFC, UHM and UI, depending on the populations. The DNA markers reported herein will assist selecting superior fiber traits especially strength in breeding, with a recommendation that the parental cotton lines should be analyzed using DNA markers within the QTL peak area before fully implementing marker assisted selection in a cotton breeding program.