Influence of chemicals and girdling on tree physiology and fruiting of litchi

Abstract

Present study was conducted to evaluate the effect of various chemicals (paclobutrazol, KNO3, Prohexadione Ca, salicylic acid, KH2PO4 and spermidine) and girdling on plant growth, tree physiology, fruit yield and quality in litchi cv. China. Experimental results revealed least increase in the tree height (1.58%) after spray of KNO3. Girdling significantly increased the tree girth (3.55 %) and trunk cross sectional area (7.29%). All the treated trees had 20-50% more leaf relative water content (RWC) than that of the control trees. Paclobutrazol (PBZ) application and spray of KH2PO4 recorded maximum value of the stomatal conductance (gs) and transpiration rate (E) at flower bud differentiation stage. The untreated trees had low stomatal conductance (gs), transpiration rate (E) and internal CO2 concentration (Ci). The transpiration rate was observed to be higher during flowering than the FBD stage. PBZ application showed the highest free proline and total phenol contents in leaves. The water use efficiency (WUE), mesophyll efficiency (ME) and carboxylation efficiency (CE) were found to be high during flowering compared to flower bud differentiation (FBD) stage. The Pro-Ca showed the maximum WUE followed by application of KNO3. Highest number of floral panicle (3656) and yield(2427 fruits /tree & 55.42 kg/ tree) were recorded with the spray of KNO3 followed by girdling. The colour intensity of fruits was improved a lot in terms of hue, value and chroma.