Embriogenic Callus Induction of Carica papaya L. cv Caliso and Callina

Abstract

Somatic embryogenesis papaya is an alternative way to produce true-to-type plants on a mass scale. The current study aimed to obtain a somatic embryogenesis protocol of Caliso and Callina cultivars in vitro with a combination of plant growth regulator 2,4-D (2,4-dichlorophenoxy acetic acid) and sucrose. The research was conducted at the Tissue Culture Laboratory of the Center of Tropical Horticulture Studies, IPB University, from November 2018 to February 2020. The explant used were immature zygotic embryos of Caliso and Callina papaya. The experiment was arranged in a factorial in a completely randomized block design. This study was divided into two experiments: a) concentration optimization of 2,4-D and sucrose for callus induction. The first factor was concentration of 2,4-D consisted of 9.05; 22.6 and 45.2 µM. The second factor was concentration of sucrose consisted of 30 and 60 g L-1. and b) concentration optimization of 2,4-D for the proliferation of embryogenic callus on solid and liquid medium. The first factor was concentration of 2,4-D consisted of 4.52; 6.78 and 9.04 µM. The second factor was culture system (solid and liquid). Papaya callus induction in addition with 2,4-D 9.05 µM and sucrose 30 g L-1 produced 92.50% of callus Caliso and 100% for Callina. The best treatment 2,4-D concentration for embryogenic callus proliferation was 6.87 µM in solid medium for Caliso cultivar, while Callina cultivar used 4.52 µM of 2.4-D in solid medium.
Keywords: 2,4-dichlorophenoxy acetic acid, callus persentage, embryogenic callus, sucrose