Induced mutagenesis in recombinants and their parents in soybean [Glycine max (L.) Merril L]

Six soybean accessions viz., TNAU S 7, TNAU S 55, DS 9501, TS 82, Himso 1563 and CO 2 and their 15 F₁ and five F₂ populations were taken with the objective of studying their response to gamma radiation. Among the parents, TS 82 and Himso 1563 were highly sensitive while CO 2 was less sensitive to the mutagen. Analysis of variance showed significant differences among treatment combinations for all the traits except number of seeds per pod. High frequency of chlorophyll mutants viz., 4.0 per cent at 3.0 grey for TNAU S 7 and 4.5 per cent for Himso 1563 at 2.5 grey occurred. Morphologically variable viable mutants during early phase of the crop and aberrants with modified stem structure, plant structure, dwarf, gigas, stunted, leaf morphology, small leaves, flower colour, pod colour, sterile, partially sterile, four seeded, small seeded, bold seeded, seed coat colour and high yielding mutants during the later stages were observed. High heritability coupled with high genetic advance was noted for plant height (TNAU S 7/TS 82 at control and at 2.5 grey, and DS 9501/TS 82 at control), number of clusters per plant (TNAU S 7/TS 82 at 2.5 grey), total number of pods per plant (DS 9501/TS 82 at 2.5 grey, TNAU S 7/TS 82 at control and at 2.5 grey) and total dry matter accumulation (DS 9501/TS 82 at 3.0 grey). Directional selection in these populations may improve the yield attributes which will in turn increase the grain yield in soybean