LW7 marker application for sweet sorghum breeding in BC3F2

บทคัดย่อ

In conventional breeding, test cross of segregating populations is required to identify the B-line plants during line development processes. The objectives of this study were to apply the LW7 molecular marker associated with the restoration of male fertility gene in sorghum to facilitate the selection for B-line plants in the BC3F2 generation of the cross between grain sorghum “KU03B” (maintainer line or B-line) and sweet sorghum “SSV84” (restorer line or R-line), and to use phenotypic selection of individual plants from F2 to BC3F2 generations of backcrossing for total soluble solid (TSS) and other agronomic traits. The LW7 marker successfully identified B-line plants in the BC3F2generation with the ratio of 1 sterile plant to 3 fertile plants. On the successive backcrossing for four generations, segregation patterns of the backcross generations shifted towards high TSS, indicating that backcrossing increased the chance to obtain the B-lines with higher TSS. Based on B-line, TSS and other agronomic traits, 23 plants in the BC3F2 generation were selected for further conversion to A3 cytoplasm specific to rf4 gene and hybrid development.