PRELIMINARY STUDIES ON EFFECTS OF GAMMA RAY ON SEED RETENTION INDICES OF THREE NIGERIAN SESAME (SESAMUM INDICUM L.) VARIETIES

Abstract

In an attempt to improve sesame for reduction of seed loss due to shattering of capsule at harvest, the seeds of three varieties of sesame (NCRIBEN-04E, NCRIBEN-01M and NCRIBEN-03L) were treated with five different doses (0, 250, 350, 450 and 550 Gy) of gamma irradiation; 0 Gy being the control. All the treatments including the controls, were grown and monitored till maturity. The seed retention power of the treatments were assessed. From the results, the treatment due to 550 Gy had highest score (6) for both NCRIBEN-04E and NCRIBEN-01M and was categorized as non-shattering (NSH) type. All other treatments were categorized as shattering (SHA) type. Similarly all the treatments from NCRIBEN-03L were categorized as SHA with treatment due to 250 Gy having highest score (5). The three varieties showed positive correlations between the seed/capsule in upright (U) and seed/capsule in inverted (I) position but NCRIBEN-01M was not significant (r = 0.650). The NCRIBEN-04E showed negative correlation between U and length of suture (L) and I and L (r = -0.570 and -0.358 respectively). This result has shown that the dose 550 Gy seems to be promising in generating mutants with high resistance to capsule shattering in sesame. There is need to advance these mutants to M2 and M3 generations to ascertain this seed retention capacity.