Indian Journal of Science and Technology

Abstract

Morphological mutants in sesame (Sesamum indicum L.; Family : Pedaliaceae) with distinctive marker traits namely leaf of narrow type, elongated, thick, ovate, ternate with long petiole and with white and pigmented flowers induced following X-ray and gamma-ray irradiations showed monogenic recessive inheritance. Control and mutants had 2n = 26 chromosomes always and the chromosomes formed bivalent (control: 12.93/cell, mutant: 12.26/cell to 12.93/cell) and univalents (control: 0.14/ cell; mutant 0.14/ cell to 1.48/ cell) which tended to form variable groups (3 to 10) in 46.81% to 65.20% meiocytes (8 group class being frequent). Univalent frequency/cell was relatively higher in long petiole (1.48/cell). Predominant chromosomal association noted among the plant types was 13 II (control: 92.96%; mutants: 50.00 % to 95.88%). Anaphase I segregation of chromosome was mostly equal (13/13) in the plant types (control: 100.0%, mutant: 98.80% – 100.00%). Pollen fertility was 83.50% in control and varied from 38.90% to 80.20% in the mutants. Pollen fertility and A1 chromosome separation was non-correlated. Analysis of quantitative parameters at M4 (true breeding plants were assessed by RBD with three replications each) revealed that most of the mutants (thick leaf, narrow leaf, elongated leaf) were beneficial for their direct selection, while the others may be exploited in cross breeding programme.
Keywords: Sesame, mutants, marker traits, cytogenetics and agronomical features.