Physiology of shoot gall formation and its relationship with juvenility and flowering in mango
1999
Singh, Gajendra(G.B. Pant University of Agriculture and Technology, Pantanagar (India))
Shoot gall is a major mango malady in many countries of the world. Studies conducted for several years indicate zero gall formation on young grafted and seedling plants below flowering stage. Insects caged on such plants laid no eggs. Chemicals secreted by insect nymphs in saliva were responsible for conversion of axillary and apical buds into galls. These were associated with the chemicals responsible for flowering in mango and were ineffective in their absence. Endogenous auxin level increased in infected shoots over healthy ones by 0.047 ug/g as assessed by oat coleoptile test. Total phonols on the other hand decreased by 0.70 mg/g in the infected shoots with 5.70 mg/g as against 6.4 mg/g in healthy shoots. While tryosine and tryptophan content decreased to 0.089 and 0.0128 mg/g at maximum feeding stage of nymphs in the infected as against 0.0928 and 0.0150 mg/g in healthy shoots respectively. Gibberellic acid, naphthalene acetic acid, maleic hydraxide, CCC, abscissic acid, alar did not affect gall formation except 2,4-D and 2, 4, 5-T (100 mg/kg and above) which gave rise to abnormal galls with open scales and elongated axis.
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