Determination of optimum leaf nutrient concentration norms for a number of mango cultivars: year II.
Oosthuyse S. A.
Author Affiliation: HortResearch SA, P.O. Box 3849, Tzaneen 0850, South Africa.
: 8-13
Abstract : Spot leaf norms were determined from selected groups of mango trees situated at various locations in Hoedspruit region and Letsitele Valley of South Africa. Some of the groups have a history of producing fruits of outstanding quality. The cultivars Tommy Atkins, Sensation, Heidi, Kent and Keitt were included. In November 1998, a leaf sample was taken from each tree for nutrient analysis. At harvest, a fruit sample, comprising 20 to 30 randomly selected fruits, was taken from each tree for quality evaluation. Each tree was assigned an index (tree quality index or TQI) based on target market acceptability of the fruits. The spot leaf norm for a mineral nutrient was taken as the concentration of the nutrient occurring with the greatest frequency in the outstanding trees. In addition, the relationship between TQI and tree yield, average fruit weight (fruit size) or number of fruits retained was determined. This was done to ascertain whether the trees producing fruits of outstanding quality were superior bearers or not. In general, TQI and tree yield or number of fruits retained were positively correlated. The nature of correlation between fruit weight and TQI differed with respect to cultivar.