Working group session:
Structural Genomics
Presentation type:
poster
Authors:
Yuan, Youlu; Wang, Tiankang; Shi, Yuzhen; Shang, Haihong; Liu, Aiying; Li, Junwen; Gong, Juwu; Gong, Wankui; Chen, Tingting; Li, Botao; Wang, Tao
Presenter:
Yuan, Youlu
Correspondent:
Yuan, Youlu
Abstract:
Plenty of QTLs for cotton fiber quality had been mapped, which provides an opportunity for molecular marker-assisted breeding in cotton fiber quality., It is necessary to pyramid a few QTLs to improve cotton fiber quality, because there is small effect to fiber quality for single QTL. In this research, three elite fiber quality lines (HS427-10, 7235 and 0-153), and two commercial cotton cultivars (TG41 and sGK156) were used as parents to develop three double-cross F1 and F6 populations of （sGK156×HS427-10）× (0-153×7235),（TG41×HS427-10）× (0-153×7235) and（sGK156×0-153）× (sGK156×HS427-10). Thus, the pyramiding effect of major QTLs of cotton fiber strength by molecular marker assisted selection was studied. For QTL-1, QTL-2 and QTL-3, linked to marker NAU1262, CM67 and TMK19, MUSS034, respectively, there was significant genetic effect. In three double-cross F1 populations, the average fiber strength of individuals whose genotype denoted as “+”, was 31.00~33.35cN/tex, and 31.00~33.39cN/tex for the individuals denoted as “+-”. Selection effects of single marker were 0.80-1.51cN / tex. In three double-cross F6 populations, the average fiber strength of individuals detected by molecular markers was higher than that detected by no markers, and existed significant or extremely significant difference in at least one population. The average fiber strength of individuals whose genotype denoted as “++/+”, was 31.99~33.46 cN∕tex. Selection effects of single marker were 0.36~2.47 cN/tex. QTL-4, QTL-5 and QTL-6 were linked to marker BNL1694, NAU1048 and BNL1421, respectively. In three double-cross F6 populations, the average fiber strength of individuals detected by molecular markers was higher than that detected by no markers, and existed significant or extremely significant difference in at least two populations. The average fiber strength of individuals whose genotype denoted as “++/+” was 30.89~33.06 cN∕tex, and 30.74~32.56 cN/tex for the individuals denoted as “+-”. Selection effects of single marker were 0.13~1.48 cN/tex. In the three double-cross F1 populations, 26 combinations were produced through comparing the average fiber strength of pyramiding two QTLs with that of pyramiding one QTL. Of 22 combinations (84.6%), the average fiber strength of individuals with two QTLs was higher than that of individuals with one QTL. Of 11 combinations (42.3%), it reached to significant or extremely significant level. The average fiber strength of individuals with two QTLs was 31.69~33.52 cN∕tex. The selection effect was 0.63~1.74 cN∕tex compared to the individuals without QTL; and 0.20~1.18cN∕tex compared to one QTL. In the three double-cross F6 populations, 75 combinations were produced through comparing the average fiber strength of pyramiding three of six QTLs with that of pyramiding two QTLs. Of 63 combinations (84.0%), the average fiber strength of individuals pyramiding three QTLs was higher than that of individuals pyramiding two QTLs. Of 13 combinations (17.3%), it reached to significant or extremely significant level. The average fiber strength of individuals pyramiding three QTLs was 31.40~36.55 cN∕tex. The selection effect was 0.77~6.10 cN∕tex compared individuals pyramiding none of the three QTLs; 0.04~6.41 cN∕tex for pyramiding one of the three QTLs; and 0.01~4.74 cN∕tex for pyramiding two of the three QTLs. Therefore, cotton fiber quality could be effectively improved by pyramiding multiple QTLs. Keywords: cotton; fiber strength; QTLs; pyramiding effect; molecular marker assisted selection