Improved Micropropagation Protocol and Molecular Marker Based Genetic Stability Assessment of Black Pepper (Piper nigrum L.)

Abstract

Black pepper (Piper nigrum L.) is a highly commercial and valuable spice crop in the world, plants of which have originated from Western Ghats region of southern India. An efficient and reliable micropropagation protocol is reported in this paper, which can be utilized for multiplication of elite genotypes of black pepper. Shoot regeneration was induced on Murashige and Skoog (MS) and Woody Plant Media (WPM) media in 24 combinations with plant growth regulators. Explants cultured in MS media supplemented with 0.5 mg L-1 BAP formed 6.5 nodes per plant with longest shoots (10.42 cm) after 12 wks. Regenerated shoots were rooted on MS media supplemented with 2.0 mg L-1 IBA, yielding about 15 roots per plant with an average root length of 3.40 cm within 4 wks. The hardening of the shoots under a mist chamber conditions (25±2 °C, 70-80% RH) yielded 100% survival after acclimatization. Genetic stability analysis of the micropropagated and mother plants was done using 48 ISSR markers. The plants found to be genetically stable when compared with mother plants. A ratio of 1:6.5 numbers of nodes is obtained on the MS medium supplemented with 0.5 mgL-1 of BAP within 3 months. This research presents an improved and efficient micropropagation protocol with good rate of multiplication of the genetically stable plants that are easily acclimatized to the field conditions.