In Vitro Shoot Regeneration of NAA-Pulse Treated Plumular Leaf Explants of Cowpea

Abstract

Cowpea (Vigna unguiculata L.) is an economically important grain legume crop and is an important source of dietary protein in many of the developing countries. The present study reports the effect of pulse treatment duration, concentration of NAA and presence of NAA in the culture medium on shoot regeneration from plumular leaf explant of Turkish cowpea cv. ‘Akkiz’ and ‘Karagoz’. Pulse treatment of mature embryos with 20 mg l-1 NAA for 1 and 3 weeks followed by culturing of plumular leaf explant on MS medium containing 0.25, 0.50 and 1.0 BAP with 1.0, 2.0 and 4.0 mg l-1 NAA promoted somatic embryogenesis in both cultivars. Longer duration of pulse treatment was deleterious resulting in browning and consequently death of the embryos on explants. Pulse treatment with 20 mg l-1 NAA for one week was less deleterious and developed two plantlets after the explants were transferred to MS0 medium after 6 weeks through somatic embryogenesis in cv. ‘Akkiz’. Pulse treatment with 10 mg l-1 NAA for 1 week showed 33.33-50.00% and 25.00-50.00% shoot regeneration frequency in cv. ‘Akkiz’ and ‘Karagoz’ respectively on MS medium containing 0.25-1.00 mg l-1 BAP. Maximum number of 2.50 shoots each per explant were recorded in cv. ‘Akkiz’ and ‘Karagoz’ on MS medium containing 1.00 and 0.50 mg l-1 BAP respectively. Contrarily, maximum shoot length of 8.98 cm of cv. ‘Akkiz’ and 9.42 cm of cv. ‘Karagoz’ was recorded on MS medium containing 0.50 mg l-1 BAP and 1.00 mg l-1 BAP respectively. Regenerated shoots were rooted on MS medium containing 0.5 mg l-1 IBA and and acclimatized in growth room at room temperature where they produced viable seeds.