Morpho-physiologic and genetic characterization of two different infertile mutants of sesame

Sesame (Sesamum indicum L.) is considered as an oil crops however it has a gradually increasing demand due to having proven its health benefits in different ways. Infertility can be used in plant breeding, seed production and in basic and applied research regarding reproduction biology in various ways. Infertility causing no seed set is governed by different mechanisms. The two basic mechanisms are "Incompatibility" and "Infertility" mechanisms that arise from the inability of the reproductive organs to function to set seed. Infertility occurs as "female organ infertility", caused by the non-functionality of female organs, "male infertility" caused by non-functional male organs, and also "male-female organ infertility" originating from the both. And in all three cases no seed is formed in a plant of a normally self-fertilizing. While female fertility has not found much application area other than basic investigations, male fertility has been extensively studied and it has been used in various forms in practice. It is known that there are two basic types of male sterility genetically, arising from nuclear and cytoplasmic factors. The aims of this thesis study performed during 2013-2014 were (i) to characterize the sterility type (male, female or both) of two different sesame mutants, St-6 and St-20, which were obtained in two separate mutagenesis program by applying gamma-rays within the scope of Antalya Mutation Project of Antalya-Sesame sub-program; to determine the heritability of these sources of infertility by Chi-square test, and to compare their morpho-physiologic characteristics with fertile siblings and also to insight on their usage possibilities in practice and basic research. The study based on regular crossing experiments with different genotypes, revealed that the sterility type in the both of the mutants studied (i) arose from both female and male organ sterility; (ii) the sterility is governed by a single recessive gene pair; (iii) the sterile flowers are easily distinguished with greenish indehiscent flat and tiny anthers as morphologic markers, but normal looking- and healthy stigma at the time of anthesis. The sterile plants are also distinguished by their more branching and taller plant height than their fertile sibs in the same progeny. Since there is no possibility to obtain seed set by artificial crossing, the sterility factor is inherited and continued by selfing the heterozygous (St/st) genotypes. It was further concluded that these sterility sources obtained by induced mutagenesis should be useful for basic studies regarding reproduction anomalies.