2017 ASHS Annual Conference

Moringa oleifera Lam. (miracle/ horseradish/ drumstick tree) is a fast growing, drought tolerant tree with numerous beneficial uses, such as for nutritious food, animal forage, green manure, water purification, traditional medicine and bio-fuel (Anwar et al., 2007). Flowering and fruiting patterns of moringa varies from location to location and from season to season within locations. Above information for sub-tropical regions (sub-optimal conditions) in South Africa are unknown. Also, moringa showed irregular bearing which needed to be investigated. Research was conducted at the University of Pretoria Experimental Farm (25°45'08.6"S, 28°15'30.5"E) in Gauteng. An eight year old moringa orchard with trees spaced at 2m X 2m under drip irrigation was studied. Trees used were pruned down to about 2m after fruiting in 2014, a year prior to the study. Both trials were statistically laid out and analysed. In the first trial, trends of flowering from bud development to fruit set and fruit maturity were observed during the year to determine the duration of each plant’s reproductive stage. One floral panicle from ten randomly chosen trees was selected for each time period. The duration of each stage was followed and recorded over a 12 month period. In the second trial, a ‘low carbohydrate reserve’ being the most obvious explanation for ‘alternate’ bearing was investigated. Changes in starch concentrations for different plant parts (root, branch, shoot, leaf, fruit and seed) were monitored between 16 flowering trees (control) which were left to flower and produce fruit and 16 de-flowered trees of which the flowers were stripped at the onset of the flowering cycle. Results from the first trial showed that flower numbers per panicle reached a peak during September and October (spring season) which were significantly higher compared to other warmer months and then slowed down during the coolest months of the year. Fruit set was almost absent during the cold season but was abundant towards the warmer months from August to February. In the second trial there were significant differences with starch concentrations between the flowering and de-flowered trees. There were also significant differences in the mean starch concentrations among the different plant parts and reproductive stages (flowering, fruit-elongation, fruit-filling and fruit-maturity) during development. A timeline chart for different phenological stages is illustrated for Moringa trees growing in a sub-tropical region. Variation in starch reserves between stems, leaves, shoots, fruit, seeds and roots and how flowering and fruiting affect the concentration of starch in these plant parts, is described.