DIRECT SOMATIC EMBRYOGENESIS FROM MATURE SEXUAL EMBRYOS OF TWO TOMATO HYBRIDS

Abstract

An experiment on the effect of three cytokinins and NAA on direct somatic embryos induction was conducted. The explants were sexual embryos, hypocotyls and cotyledenous leaves of two hybrids of tomato, Choorouk and GS-12. Four levels of BA, Kin or TDZ (0.00, 0.01, 0.10, 1.00) mg/l and three concentrations (0, 1, 2, 3) mg/l of NAA were tested. A histological study to investigate the stages of direct somatic embryos initiation was implemented. The results indicated that the source of explants was effective on somatic embryos initiation for both hybrids under study. Somatic embryos were not induced from hypocotyls and cotyledenous leaves, however, sexual embryos for both hybrids were superior on somatic embryogenesis. Choorouk sexual embryos cultured on MS medium supplemented with 80 g/l of sucrose; 0.01 mg/l of TDZ and 2 mg/l NAA gave 90% somatic initiation percentage with 13.1 somatic embryos. While GS-12 sexual embryos cultured on MS medium modified with 80 g/l of sucrose; 0.1 mg/l of TDZ and 2 mg/l NAA resulted in 90% somatic initiation percentage with 13.5 somatic embryos. The study confirms that the sexual embryos are the best explants on somatic embryos initiation for both tomato hybrids. Further research and evaluation needs to be done to study the physiological effects of plant growth regulators on somatic embryos growth and development.