Effect of Explants and Hormone Levels on Callus Induction in Tomato (Lycopersicon esculentum mill.): Variety Thilina

Abstract

Tomato (Lycopersicon esculentum Mill) is a major vegetable crop that has achieved tremendous popularity over the last century and it is grown in almost every country of the world, including Sri Lanka. An efficient in vitro propagation technique is required for the genetic improvement of this crop via gene transfer technology. The initiation of callus cultures is the first step for an efficient in vitro propagation technique of this crop as well as other crops. To improve Sri Lankan tomato varieties genetically, this study was conducted to investigate the influence of explants and hormone levels on callus induction of tomato (Lycopersicon esculentum Mill): Variety Thilina as the pioneer step. Five different hormone combinations on Murashige and Skoog's (MS) basal medium with 0.1 mg/1 NAA (1-Naphthalene acetic Acid) + 1.0,1.5,2.0,2.5,3.0 mg/1 BAP (Benzyl Adenine) as well as three explant types: hypocotyl, leaves and root were employed. Completely Randomized Design (CRD) was used as experimental design with 5 replicates. Statistical analysis was carried out using the Student Newman-Kuells Means Separation Test. Fresh weights of callus were evaluated after one month of culture establishment. Maximum callus production from hypocotyls and leaves were -obtained on MS medium supplemented with NAA 0.1 mg/1 and BAP 2.0 mg/1 while root explants did not produce calli. Hypocotyls recorded to be better explants for the callus production (0.33 g/ explants).