Effect of KNO3 spray to flowering mango trees on fruit retention, fruit size, tree yield, and fruit quality.
Oosthuyse S. A.
Author Affiliation: Merensky Technological Services, P.O. Box 14, Duivelskloof 0835, South Africa.
Yearbook - South African Mango Growers' Association 16 : 27-31
Abstract : In South Africa, the mango cultivars Tommy Atkins, Kent and Heidi retain few fruits relative to the cultivars Sensation, Irwin and Keitt. In trials in 1992 and 1993, the effect on fruit retention, fruit size, tree yield and fruit quality of inflorescence applications of KNO3 to trees of the former cultivars was investigated. A KNO3 spray at 2 or 4% was administered either once during the flowering period, i.e. when the inflorescences were in full-bloom, or twice during this period, i.e. when the inflorescences were actively developing and subsequently when they were in bloom. In Tommy Atkins, the greatest increase in fruit number occurred following the single application at 4%. In Heidi, 2 applications at 4% each gave rise to the greatest increase, and in Kent, 2 applications at 2% each gave rise to the greatest increase. In each cultivar, slight reductions in average fruit weight were associated with the increases in fruit retention found. In every cultivar, increases in yield occurred. The greatest increases in yield corresponded to the greatest increases in fruit retention. There was no apparent effect of the KNO3 sprays on fruit quality (ground skin coloration, total soluble solids content, pH, or taste on ripening).