An Efficient Protocol for Whole Plant Regeneration via Auxiliary Bud Explants and Molecular Confirmation of Pigeonpea [Cajanus cajan (L.) Millsp.] Regenerated Plants

In vitro regeneration of pigeonpea through organogenesis was achieved via auxiliary buds as explants from the field grown plants of seven varieties and two hybrids under the influence of variable concentrations of two cytokinins; BAP and Kinetin, shoot induction of variable morphology, was observed for all the cultivars. Incidentally, hybrids GRPH-1 and GRPH-2 displayed highest regeneration (100%) ability. BAP was found to be most effective with maximum regeneration (mean of 72.83%). Elongation of shoots was achieved on MS medium supplemented with BAP in combination among NAA and GA 3. The treatment of 2 mg/l BAP + 1 mg/l NAA + 2 mg/l GA 3 was found to be most effective in shoot elongation. The elongated shoots were successfully rooted on MS medium containing different concentrations of auxins; IBA 1 mg/l induced maximum frequency of roots in all the cultivars (mean of 74.81%) followed by IAA. Molecular confirmation using 12 SSR primers screened both parents and regenerated plants could conclude that 7 markers showed monomorphism/homozygous bands confirming that the regenerated plants were genuinely true-to-type to the mother plants. Further, SCAR markers; SCAR-704 and SCAR-N-18 that are linked to Fusarium wilt and SMD susceptibility reaction respectively were screened both parents and regenerated plants. BSMR-736 and Gulyal Red were susceptible to Fusarium wilt. Genotypes GRPH-1, GRPH-2, Gulyal Red, Maruthi, TS-3R, BSMR-736 and WRP-1 suggesting susceptibility to SMD through marker analysis. This technology finds its place in seed production where one genuinely DNA fingerprinted plant of a specific variety can be in vitro multiplied and linked to transplanting pigeon pea with seed production either on small scale and/or on a commercial scale.