Preconditioning effect of cytokinins on in vitro multiplication of embryonic node of grass pea (Lathyrus sativus L.) cultivar Gürbüz

Authors: SURENDRA BARPETE, MUHAMMAD AASIM, KHALID MAHMOOD kHAWAR, SANCAR FATİH ÖZCAN, SEBAHATTİN ÖZCAN

Abstract: Lathyrus sativus L. (grass pea) is an important grain legume crop grown all over the world. It is very recalcitrant and difficult to regenerate under in vitro conditions. The present study determined the effect of preconditioning of cytokinins [10 and 20 mg L^{-1} thidiazuron (TDZ) and 2-isopentenyl adenine (2iP)] and postconditioning of dissimilar levels of TDZ-indole-3-butyric acid (IBA) and 2iP-IBA on in vitro shoot multiplication using embryonic node explants. The results showed that preconditioning followed by postconditioning on Murashige and Skoog (MS) medium with 0.25, 0.50, 0.75, and 1.0 mg L^{-1} 2iP or TDZ combined with 0.10 mg L^{-1} IBA had positive effects on shoot multiplication. It seemed as if the TDZ-preconditioned and TDZ-IBA-postconditioned explants were more regenerative compared to 2iP-preconditioned or 2iP-IBA-postconditioned explants. Maximum shoot induction (100%) was achieved on MS medium containing 1 mg L^{-1} TDZ and 0.10 mg L^{-1} IBA, with a mean number of 31.10 shoots per explant. In comparison to the other cytokinin tested, 2iP-preconditioned and 2iP-IBA-postconditioned explants had longer shoots, with a mean shoot length of 8.10 cm. Root initiation was observed on all cultures 4 weeks after the transfer of shoots with the best rooting on MS medium containing 2 mg L^{-1} IBA. The rooting response was 76.56% with a mean number of 8.03 roots per shoot and root length of 8.2 cm. The healthy plants were transferred to a greenhouse for acclimatization and exhibited 90% survival. It was concluded that TDZ preconditioning was necessary for grass pea multiplication along with TDZ-IBA postconditioning. This regeneration protocol may facilitate future genetic transformation and breeding studies to reduce \Beta-N-oxalyl-L-\Alpha,\Beta-di-amino propionic acid content in grass pea.

Keywords: Embryonic node, grass pea, Lathyrus sativus L., regeneration

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