Synergistic effect of silver nitrate and coconut water on shoot differentiation and plant regeneration from cultured cotyledons of <i>Capsicum annuum</i> L.

Abstract

Chili pepper (<i>Capsicum annuum</i> L.) ranks among the most important vegetable crop belonging to the family Solanaceae that is consumed both as vegetable and spice throughout the world. <i>C</i>.<i> annuum</i>, as crop, in order to meet the target yield, demands improved variety that could overcome environmental challenges <i>viz</i>., biotic and abiotic stress. Cultivar improvement essentially requires an efficient <i>in vitro</i> regeneration protocol. In the present study, we investigated the influence of silver nitrate (AgNO₃) and coconut water, individually as well in combination, on <i>in vitro</i> shoot elongation and plant regeneration from cotyledon explants of <i>C</i>.<i> annuum</i> cv G-4. Shoot buds were induced on shoot bud induction medium supplemented with either 44.38 µM 6-benzylaminopurine (BAP) or 9.0 µM thidiazuron (TDZ) along with 5.77 µM gibberellic acid (GA₃) and 14.7 µM phenyl acetic acid (PAA). Elongation of shoot buds was obtained on elongation medium containing 8.87 µM BA or 0.45 µM TDZ, 5.77 µM GA₃ and 14.7 µM PAA followed by rooting in 9.8 µM indole-3-butyric acid (IBA). All the media were supplemented with 30 µM AgNO₃ and/or coconut water (10% v/v). The presence of coconut water in the elongation media enhanced the regeneration of well developed shoots from differentiating explants on TDZ media while AgNO₃resulted in enhanced production of rooted shoots with greater influenceon emerging shoots from BAP mediaupon transfer to rooting media. There was synergistic response with further enhancement of elongated shoots/elongated rooted shoots on the combined use of coconut water and AgNO₃. The elongation media produced significantly higher total shoots when AgNO₃ was used synergistically with coconut water (59.0%) as against AgNO₃ alone (38.0%). While in rooting media, there was significantly higher production of elongated rooted shoots when coconut water was used synergistically with AgNO₃ (47.2%) as against the coconut water alone (14.4%).