Author
GUO, YUFANG - MISSISSIPPI STATE UNIV | |
McCarty, Jack | |
Jenkins, Johnie | |
AN, CHUANFU - MISSISSIPPI STATE UNIV | |
Saha, Sukumar |
Submitted to: Euphytica
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 9/4/2008 Publication Date: 2/1/2009 Citation: Guo, Y., McCarty Jr., J.C., Jenkins, J.N., An, C., Saha, S. 2009. Genetic detection of node of first fruiting branch in crosses of a cultivar with two exotic accessions of upland cotton. Euphytica. 166:317-329. Interpretive Summary: Photoperiod sensitivity of exotic cotton accessions impedes their use in breeding programs. Quantitative trait locus (QTL) analysis was conducted in two second generation populations from crosses between a day-neutral cultivar Deltapine 61 and two photoperiod sensitive accessions T1107 and T1354. Node of first fruiting branch was used to measure relative time of flowering under a long day summer growing season in Mississippi and a short day condition in the greenhouse. Different flowering patterns were observed in the two populations. In the T1107 population resulting from the cross with Deltapine 61 plants started flowering at a lower node and more plants flowered than in the T1354 population. Two QTLs were found that accounted for 28.5% (qNFB-c21-1) and 15.9% (qNFB-c25-1) of the flowering variation in population T1107; whereas, one major QTL (qNFB-c25-1) explained 63.5% of the flowering variation in population T1354. Genetic segregation analysis and QTL mapping results provide further information on the mechanisms of cotton photoperiodic sensitivity. Technical Abstract: Flowering time is an adaptive trait of crops with biological and agricultural significance. In Upland cotton (Gossypium hirsutum L), photoperiod sensitivity of exotic accessions impedes their use in breeding programs. Quantitative trait locus (QTL) analysis was conducted in two F2 populations from crosses between a day-neutral cultivar Deltapine 61 (DPL61, PI 607174) and two photoperiod sensitive, G. hirsutum accessions (T1107, PI 607174 and T1354, PI 530082). Node of first fruiting branch (NFB) was used to measure relative time of flowering under a long day summer field growing season in Mississippi and a short day condition in the greenhouse. Different flowering patterns were observed in the two populations. QTL mapping results also indicated differences between the two populations. Two QTLs were found across five scoring dates and accounted for 28.5 (qNFB-c21-1) and 15.9% (qNFB-c25-1) of the phenotypic variation, respectively, at the last scoring date in Pop.1107 (DPL61 × T1107); whereas, one major QTL (qNFB-c25-1) explained 63.5% of the phenotypic variation at the last scoring date in Pop.1354 (DPL61 × T1354). Additionally, two suggestive QTLs (qNFB-c10-1 and qNFB-c23-1) were detected in Pop.1107, but less phenotypic variation was explained (~10%), indicating smaller effects. Suggestive QTLs appeared at various scoring date(s) in both populations indicating their roles in regulating flowering at lower or higher node number. Genetic segregation analysis and QTL mapping results provide further information on the mechanisms of cotton photoperiodic sensitivity. |