Author
GUO, YUFANG - MISSISSIPPI STATE UNIV | |
McCarty, Jack | |
Jenkins, Johnie | |
Saha, Sukumar |
Submitted to: Euphytica
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 10/29/2007 Publication Date: 6/1/2008 Citation: Guo, Y., McCarty Jr., J.C., Jenkins, J.N., Saha, S. 2008. QTLs for node of first fruiting branch in a cross of an upland cotton, Gossypium hirsutum L., cultivar with primitive accession Texas 701. Euphytica. 163:113-122. Interpretive Summary: Primitive cottons represent resources for improvement of fiber quality, pathogen resistance, and increased tolerances to environmental stresses. Most primitive accessions do not flower under the long days of the U.S. cotton belt. Molecular markers were used to locate quantitative trait loci (QTLs) for the main-stem node of the first fruiting branch (NFB) which is related to flowering time. An F2 population consisting of 251 plants from the cross of Deltapine 61, a day length neutral flowering cultivar, and Texas 701, a day length sensitive flowering accession, was studied. Segregation revealed the complex nature of NFB. Interval mapping and multiple QTL mapping were used to determine QTLs contributing to NFB. Single and multiple-marker data analyses were conducted. Three QTLs affecting NFB were detected on chromosomes 16, 21, and 25. Two additional QTLs with minor effects were detected on chromosomes 15 and 16. Four markers associated with these QTLs accounted for 33% of the variation in NFB. Our results suggested that at least three chromosomes contain factors associated with NFB for this population. This research provided a better understanding of the genetic factors of flowering time in cotton. Technical Abstract: Primitive cottons (Gossypium spp.) represent resources for genetic improvement for fiber quality, pathogen resistance, and increased tolerances to environmental stresses. Most primitive accessions are photoperiod sensitive and do not flower under the long days of the U.S. cotton belt. Molecular markers were used to locate quantitative trait loci (QTLs) for node of first fruiting branch (NFB) which is related to flowering time in cotton. An F2 population consisting of 251 plants from the cross of Deltapine 61, a day neutral cultivar, and Texas 701, a photoperiod sensitive accession, was used in this study. Segregation in the population revealed the complex characteristics of NFB. We employed interval mapping and Multiple QTL Mapping by MAPQTL 5.0 to determine QTLs contributing to NFB. Single and multiple-marker analyses were conducted using regression models. Three major QTLs affecting NFB were detected on chromosomes 16, 21, and 25. Two additional QTLs with minor effects were detected on chromosomes 15 and 16. Four markers associated with these QTLs accounted for 33% of the variation in NFB. Two pairs of epistasis interaction between markers were detected. Our results suggest that at least three chromosomes contain factors associated with NFB for this population with some epistasis interactions. Our research provided a better understanding of the genetic factors of flowering time in cotton. |