This thesis dissertation, presented by Mr. Komivi Dossa, is submitted to the Graduate School of Chinese Academy of Agricultural Sciences in partial fulfillment of the requirements for the award of Doctor of philosophy degree in Crop Genetics and Breeding (Year 2017).
Drought is an important abiotic stress that impairs sesame production in the world, especially in drought-prone environments of West Africa. However, limited studies have focused on drought issues so far. In this PhD study, a large sesame germplasm was characterized for the first time for drought tolerance and the genetic basis of drought tolerance in sesame was examined. A high level of genetic diversity was found within the sesame germplasm which is important for the genetic improvement. Also, some highly drought tolerant genotypes were discovered that could be proposed to farmers in West Africa. Furthermore, this study released some important gene expression data from temporal transcriptome sequencing which revealed 61 key genes conferring high drought tolerance in sesame. Finally, for the first time, the genetic basis of drought tolerance traits were examined in sesame through genome-wide association studies which successfully unraveled potential allelic variations modulating drought tolerance. It delineated the superior alleles enhancing drought tolerance and also highlighted eight important QTLs including two pleiotropic regions located on the linkage groups 8 and 4. Various candidate genes modulating sesame responses to drought were uncovered in this work. Henceforth, sesame crop holds some essential biomaterial, genetic and genomic knowledge that could be applied for its improvement for drought tolerance.