The 2011 ASHS Annual Conference

The objective of the present study was to evaluate differences in growth and development of micropropagation and softwood cutting derived plants under field conditions. The work was conducted at two locations with different average chill hour accumulation (Haines City, FL and Citra, FL). At each location, during April 2010, three cultivars (‘Emerald’, ‘Jewel’ and ‘Primadonna’) were planted as a completely randomized-block design with 20 plants/plot, in a two way factorial, with six treatments and five replications. Height and width were recorded monthly from June 2010 to November 2010. Average plant width and height were used to calculate plant volume. In December 2010 (Haines City) and January 2011 (Citra) flower buds and plant height, width, number of canes, and shoot tips of two plants/plot were recorded. Major canes were defined as those larger than 0.7 mm in diameter at 12 cm above the soil line. Results were evaluated by analysis of variance and treatments were compared using Tukey’s HSD test at 5% significance level (SAS 9.2). The effect of propagation method was different depending on the location, but in both cases there was an interaction between cultivar and propagation method on plant growth. At Citra, there was a significant increase in height and width of ‘Emerald’ micropropagated plants after 9 months in the field compared to softwood cutting-derived plants. There was no significant effect of propagation method on average height or width of ‘Primadonna’ or on height of ‘Jewel’. However, average width of Jewel micropropagated plants did show a significant increase. The number of major canes/plant significantly increased when ‘Jewel’ and ‘Emerald’ were micropropagated, but there was no significant difference on canes/plant of ‘Primadonna’. The effect on flower bud number was cultivar dependent: there was a significant increase on micropropagated ‘Emerald’, but there was no treatment difference among the other cultivars. At Haines City, plant height of ‘Jewel’ and ‘Emerald’ was not affected by propagation method, but there was a decrease in height of ‘Primadonna’ tissue cultured plants. The average width of ‘Emerald’ micropropagated plants was higher compared to those obtained from rooted cuttings, but there was no effect of propagation method on plant width for the other two cultivars. Major canes/plant and shoot tips/plant significantly increased when ‘Emerald’ and ‘Jewel’ were micropropagated, but no differences between propagation methods were detected for ‘Primadonna’. The number of flower buds/plant was not affected by the propagation method for any the cultivars evaluated.