Spacing effect on macro- and micro-propagated pineapple plantlets

Productivity of pineapple (Ananas comosus L. Merr) is primarily limited by unavailability of planting material and improved management practices. This study was conducted to determine effect of spacing on growth and development of macro- and micro-propagated pineapple. Micro- and macro-propagated pineapple plantlets were evaluated at three spacings at RAB Rubona station located in mid-altitude zone of Rwanda during 2011/2012 season; the experimental design used was a randomized complete block (RCBD) with three replications. Data were collected on monthly basis by measuring plant height, length and width of longest leaf and counting the number of functional leaves. The data were analyzed by Microsoft excel and Genstat Discovery Edition 4 Software package, least significant difference test were used to determine if there is any significant difference among micro and macro-propagated pineapple plantlets in their growth resulting from spacing effect. Data were analyzed from 258th to 379th day after transplanting; At 379th day after transplanting, highly significant (P<0.001) differences among propagation modes were found for number of functional leaves, micro-propagated pineapple plantlets were found to have more number of functional leaves than macro-propagated pineapple plantlets. Significant (P<0.05) differences among macro- and micro-propagated were observed also for plant height and length of the longest leaf at 379th day after transplanting. At 379th day after transplanting, there were no significant (P>0.05) differences among micro- and macro-propagated pineapple plantlets for width of the longest leaf. Analysis of variance showed that there were no significant (P>0.05) differences among spacings for plant height, number of functional leaves, length and width of the longest leaf. Interaction between propagation modes and planting densities were found to have no significant (P>0.05) differences for all vegetative parameter. The experiment needs to be continued and repeated in other agro-ecological zones to confirm these findings.