Effect of cytokinins and their concentration regimes on multiple shoot induction using cotyledonary node with cotyledons and embryo discs with half cotyledon explants in pigeonpea (Cajanus cajan L. Mill sp.)

Pigeonpea (Cajanus cajan L. Milli sp.) belongs to family Fabaceae, ranks sixth among legumes in production, which is constrained by several biotic and abiotic stresses. Three cytokinins viz., BAP, TDZ and zeatin and their concentration regimes were tested for multiple shoot bud induction in ICPL87119 and BSMR736 pigeonpea genotypes. Fortification of growth medium with 2.0 mg/l BAP, 4.0 mg/lTDZ and 2.0 mg/l zeatin, separately, could induce maximum number of shoot buds, 53.7, 46.1 and 40.9 respectively, per explants in both, cotyledonary node with cotyledons and embryo discs with half cotyledon explants. Any further increase in tested cytokinin concentration levels imparted reduction in multiple shoot bud induction. There was no significant effect of MS nutrient strength on root induction, MS with 0.5 mg/l IBA was most suitable for healthy and number of root induction (4.8±0.7). Reported in vitro method of plantlet regeneration may be exploited for genetic engineering programs for multiple stress tolerance in pigeonpea.