Location: Tropical Crops and Germplasm ResearchTitle: Association analysis of photoperiodic flowering genes in West and Central African sorghum [Sorghum bicolor (L.) Moench] Author
|Rattunde, H. Frederic|
Submitted to: Biomed Central (BMC) Plant Biology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/7/2012
Publication Date: 3/7/2012
Citation: Bhosale, S.U., Stitch, B., Rattunde, H.W., Wiltzien, E., Haussmann, B.I., Hash, T.C., Ranu, P., Cuevas, H.E., Paterson, A.H., Melchinger, A.E., Parzies, H. 2012. Association analysis of photoperiodic flowering time genes in West and Central African sorghum [Sorghum bicolor (L.) Moench]. Biomed Central (BMC) Plant Biology. doi: 10.1186/1471-2229-12-32. Interpretive Summary: Sorghum (Sorghum bicolor) flowering is controlled by daylength and the majority of tropical sorghum germplasm flowers only during short days. This characteristic makes tropical sorghum to have limited value in temperate regions where days are longer during the planting season. In order to improve our understanding of flowering in sorghum, 219 sorghum accessions from West and Central Africa were evaluated for variation in flowering time at Samanko, Mali. Subsequently, mutations in genes related to the flowering pathway were identified and evaluated to determine their association with flowering time. Results indicate that the genes Crytochrome 1 and Gigantea have an important role in sorghum flowering time. The development of molecular markers developed in this study for these genes will aid in predicting flowering time in public and commercial sorghum breeding programs.
Technical Abstract: Photoperiod-sensitive flowering is a key adaptive trait for sorghum (Sorghum bicolor) in West and Central Africa. In this study we performed an association analysis to investigate the effect of polymorphisms within the genes putatively related to variation in flowering time on photoperiod sensitive flowering in sorghum. For this purpose a genetically characterized panel of 219 sorghum accessions from West and Central Africa was evaluated for their photoperiod response index (PRI) based on two sowing dates under field conditions. Sorghum accessions used in our study were genotyped for single nucleotide polymorphisms (SNPs) in six genes putatively involved in the photoperiodic control of flowering time. Applying a mixed model approach and previously-determined population structure parameters to these candidate genes, we found significant associations between several SNPs with PRI for the genes CRYPTOCHROME 1 (CRY1-b1) and GIGANTEA (GI). The negative values of Tajima’s D, found for the genes of our study, suggested that purifying selection has acted on genes involved in photoperiodic control of flowering time in sorghum. The SNP markers of our study which showed significant associations with PRI can be used to create functional markers to serve as an important tool for marker assisted selection of photoperiod sensitive cultivars in sorghum.