Comparison of determinate and indeterminate lines of sesame for agronomic traits

With its availability via mutation induction, determinate growth habit is now one of the prerequisites for developing cultivars of sesame with synchronous capsule maturation and thus suited to mechanized harvesting despite its natural indeterminate character. In order to assess whether six determinate sesame mutants and two determinate improved lines were capable of closing the yield gap, compared with corresponding indeterminate wild types and sibs, field experiments were performed in the three growing seasons of 1998, 1999 and 2000 in Antalya, Turkey. The seed yields of the determinate mutants and breeding lines were found to be lower than their wild types and counterparts. Plant height and fruiting zone length in the determinates were also shorter than the indeterminates while there was no difference for stem height to the first capsule. The short stature habit of the mutants may resist lodging when lodging is a problem but this was one of the factors leading to low yield compared to the indeterminates. Our observations indicated that the production practices developed for indeterminates should be modified and adapted for the determinates. These practices will include narrower row spacing and denser stands that may lead to taller plants and higher seed yield without affecting lodging.