To root tissue-cultured apple cultivars, shoots from proliferating cultures were first transferred to root induction medium with IBA for 1 week in the dark. Shoots were later transferred to the same medium without IBA and incubated under light for elongation of the roots. Rooted shoots were then transferred to Jiffy-7s supplemented with biological plant protectant and fertilizer, and incubated in plastic humidity trays. After 2 to 3 weeks, plants were transferred to pots and covered with plastic bags to facilitate acclimation. This technique has resulted in 70% to 100% of shoots selected in vitro producing vigorously growing, healthy plants in the greenhouse. Chemical name used: indolebutyric acid (IBA).
Jyothi Prakash Bolar, John L. Norelli, Herb S. Aldwinckle, and Viola Hanke
Jyothi Prakash Bolar, Susan K. Brown, John L. Norelli, and Herb S. Aldwinckle
The overall goal of our research is to develop an efficient transformation and regeneration system for `McIntosh' apple. The first objective was to determine the optimum combination of Gelrite (G) and agar (A) to maximize regeneration and minimize vitrification. Treatments included the following combinations of agar (in g–liter–1) and Gelrite (in g–liter–1): 1) 7 and 0; 2) 5.25 and 0.625; 3) 3.5 and 1.875; 4) 1.75 and 1.875; and 5) 0 and 2.5. There were 10 replications, and a single petri plate containing six leaf pieces was the unit of replication. Both 5.25(A) and 0.62(G) and 3.5(A) and 1.25(G) provided high regeneration of healthy, nonvitrified shoots. Since modification of media affects the concentration of antibiotics used in selection due to precipitation of antibiotics, the second objective was to determine the optimal concentration of antibiotic for the selection and regeneration of transformed `McIntosh' on gelrite–agar-based media. Kanamycin was tested at 0, 10, 25, 50, 75, and 100 μg–ml–1 and paromomycin was tested at 0, 50, 100, 150, 200, and 250 μg–ml–1. Antibiotic selection will be discussed relative to optimum concentration and efficiency of selection.