Pedigree Selection in Improving Seed Yield and Tolerance of Sesame to Macrophomina phaseolina (Tassi) Goid

Abstract

C HARCOAL rot caused by Macrophomina phaseolina (Tassi) Goid is the most destructive among major pathological constraints to sesame production in Egypt and worldwide. The objective of the current study was to improve high seed-yielding lines of sesame tolerant to charcoal rot through two cycles of pedigree selection for eight selection criteria under artificial infection. The base population consisted of 185 families at the F 3 -generation. Broad sense heritability was very high and ranged from 0.79 to 1. Tall plants gave large number of capsules/plant (NC/P), long fruiting zone (LFZ), high yielding ability and low infection% of Macrophomina . Number of capsules/ plant gave sizeable genotypic (0.52) and phenotypic (0.49) correlations with seed yield/plant (SY/P). After the second cycle of selection, highly significant differences were noted for the eight selection criteria. The results revealed that the selection for days to 50% flowering improved earliness, but it was better if it restricted by SY/P. Meanwhile, selection for oil% restricted by SY/P gave the best improvement from the mid-parent in SY/P (70.16%**) followed by selection for 1000SW (62.14%**), SY/P per se (55.80%**) and selection for days to 50% flowering restricted by SY/P (39.76%**). The inclusion of a trait as an independent culling level improves the efficiency of the selection. Therefore, selection index incorporating favorable traits is recommended. The eight different methods of pedigree selection decreased the infection% at harvest ranged from -3.31%** to -15.45%** from the mid-parent.