Direct Somatic Embryogenesis and Organogenesis of The Passion Fruit Plant Paassifora edulis Sims. F. Flavcarpa in Vitro

This study was conducted in the Plant Tissue Culture Laboratory, College of Agricultural Engineering Sciences, University of Baghdad, from 2022 to 2024, aiming to develop an efficient micropropagation protocol for passion fruit (Passiflora edulis Sims. f. flavicarpa) through direct organogenesis and somatic embryogenesis under in vitro conditions. Several experiments were performed, including seed germination, culture initiation, and shoot development and multiplication. The seed germination experiment evaluated the effects of medium physical state (liquid and solid) and various dormancy-breaking treatments and their interactions. The initiation stage assessed the influence of explant type (roots, embryos with cotyledons, hypocotyls, and cotyledonary leaves), 2,4-dichlorophenoxyacetic acid (2,4-D), and benzyl adenine (BA). The organ development and shoot multiplication stage examined the effects of BA, gibberellic acid (GA₃), and silver nitrate (AgNO₃). All experiments were arranged in a completely randomized design. Results indicated that the interaction between liquid medium and seed tip excision produced the highest germination rate (30%). Explant type played a critical role in inducing organogenesis and somatic embryogenesis. The highest direct organogenesis response (80%) was obtained from cotyledonary leaf explants cultured on medium containing 1 mg/L BA without 2,4-D. Direct somatic embryogenesis was maximized (40%) using cotyledonary leaf explants with 0.5 mg/L BA. The highest callus formation rate (50%) was observed in hypocotyl explants treated with 1 mg/L BA and 4 mg/L 2,4-D. For shoot multiplication, the combination of 2 mg/L BA, 1 mg/L GA₃, and 4 mg/L AgNO₃ significantly enhanced shoot number, length, and biomass.