Management of stockplant for the in vitro culture of nodal segments of guava (Psidium guajava L.)

Abstract

Nodal segments collected from shoots of adult grafts on juvenile rootstocks from seedlings grown under full sun and shade (40%), and from adult plants grown without and with shade (80%) were cultivated in vitro. In addition, nodal segments from field grown plants were cultivated in vitro under the following conditions: control; sixty days after dormex (hydrogenated cyanamide 49%) application at 2% and 4%; sixty days after partial pruning; and 75 days of 80% shading. Sixty days after culture initiation, seedlings and adult plants under shade produced no browning explants. The highest percentage of budbreak (PBB) (100%) was obtained at 20 days in explants of seedlings; at 40 days in explants of adult plants under shade. At sixty days, adult and grafted plants without shade presented 40% and 35% browning explants, respectively, and 85% and 80% budbreak explants, respectively. At sixty days, the control treatment produced 65% budbreak; the dormex treatment with the concentrations of 2% and 4%, 80% and 70% PBB, respectively; the partial pruning, 65%. Dormex application at 2% increased PBB and percentage of leaves formed to more than that of the control.