ISHS Acta Horticulturae 291: III International Mango Symposium
HORTICULTURAL ASPECTS OF MANGO MALFORMATION |
| Author: | S. Ram |
| Abstract:
Mango malformation disturbs the natural orientation of shoots and panicles and causes excessive and abnormal growth in them thereby adversely affecting the fruiting. The factors causing this abnormal behaviour in shoots and panicles has been of great concern since first discovered in 1891. Besides mites and pathogens, several other reasons assigned as the cause of the malady are discussed in the horticultural aspects of this review. Differences in the levels of nutrients in healthy and malformed panicles have been reported. Applications of N, K, Fe, Zn or Mn decreased malformation but nutrient deficiency or excess could not be proved conclusively as causative factor(s). Although no difference in C/N ratio of healthy and malformed shoots of mango seedlings were found, high levels of carbohydrates in malformed shoots and panicle have been reported as well as contradicted. Further, chlorophyll and total polysaccharides are at low levels in malformed panicles as compared to healthy ones. Amino acids, soluble proteins, total nitrogen, RNA, DNA, polyphenols and sterols reportedly are at high levels in leaves of malformed shoots. Morphactin treated panicles produced malformation-like symptoms along with high IAA oxidase and low catalase and amylase activities. Studies on endogenous hormones have revealed auxin deficiency and excess of gibberellin and cytokinin in the malformed panicles, but the role of inhibitors and ethylene remain inconclusive. The malformed panicles and shoots possessed malformin-like substances, whereas healthy panicles and shoots did not. The use of antimalformins have caused substantial reduction in the number of malformed panicles on the tree, but have failed to eradicate the malady. The future work on mango malformation is discussed in view of changing concepts on its cause and control. | |
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