Combining ability and heterosis for stem and root rot and leaf webber/capsule borer in sesame

In present investigation eighteen female parents (lines) were crossed with ten male parents (testers) in line x tester mating design and the resultant 180 F1’s were evaluated for their combining ability effects. Mean square due to genotypes, parents and hybrids were significant for stem and root rot (Macrophomina phaseolina) and leaf webber/capsule borer (Antigastra catalaunalis). The relative estimates of variance due to sca were higher than gca for all the characters indicating the predominance of non additive gene action for improving these characters. Among the female parent RT-305 and RT-325 was best general combiner for stem and root rot (Macrophomina phaseolina), whereas, among male parents IS-97, IS-100 B and IS-646-1were good general combiner for stem and root rot (Macrophomina phaseolina). For leaf webber/capsule borer (Antigastra catalaunalis) the lines RT-281, RT-46 and tester EC-370867 showed significant and negative gca effects for insect reaction, thus, they were good general combiner for utilizing in resistance breeding programme. The cross combinations RMT-97 x IS-100B, RMT-93 x IS-97, RMT-82 x EC-370823, C-50 x IS-100 B, AT-77 x EC-370823 and RT-127 x EC-370932 for stem and root rot and crosses RT-281 x EC-370867, RMT-97 x EC-370867, RMT-94 x EC-370867, RMT-93 x EC-370867 and RT-305 x EC-370867 for leaf webber/capsule borer exhibited significant negative sca effects and significant mean performance for both the characters. The above crosses showing the desirable sca effects with desirable heterosis involving to low x high and high x low gca parents for the disease and insect resistance indicating that desirable transgressive segregants may be released from these crosses in subsequent generations in sesame.