HORMONAL MODULATION OF PRODUCTIVITY AND QUALITY OF KINNOW MANDARIN (CITRUS RETICULATA BLANCO) UNDER RAINFED CONDITIONS OF HIMACHAL PRADESH
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Date
2024-02-05
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UHF,NAUNI
Abstract
The present investigations on “Hormonal modulation of productivity and quality of Kinnow mandarin (Citrus reticulata Blanco) under rainfed conditions of Himachal Pradesh” were carried out on rainfed Kinnow mandarin orchard at Regional Horticultural Research and Training Station, Dr YS Parmar University of Horticulture and Forestry, Jachh (Nurpur), District-Kangra (HP) India during the year 2020-2022. The experiment was laid out in a Randomized Block Design (Factorial) with treatment combinations of nine hormonal treatments (HBR @ 0.25 ppm, HBR @ 0.50 ppm, SA @ 5 ppm, SA @ 10 ppm, MeJA @ 10 ppm, MeJA @ 20 ppm, GA3 @ 10 ppm, GA3 @ 20 ppm, Control (Water spray)) and seven levels of the stages of hormonal spray (at fruit set (1st week of April), fruit cell expansion (1st week of June), fruit filling (1st week of October), fruit set +fruit cell expansion, fruit cell expansion +fruit filling, fruit set +fruit filling and fruit set +fruit cell expansion +fruit filling). Each treatment combination was replicated four times with four plants per replication. The results revealed that the treatment combination H2S7 i.e. homo-brassinolide spray at a concentration 0.50 ppm applied thrice respectively during period of water deficit coinciding with fruit set, fruit cell expansion and fruit filling stage registered highest increase in trunk cross sectional area, tree height, shoot extension growth, shoot diameter, tree spread, tree volume and leaf area index. Fruiting parameters viz. earliest first flower, full bloom, fruit set were also significantly higher under treatment combination H2S7. The minimum fruit drop was recorded under treatment combination H8S7 (GA3 @ 20 ppm spray at three time application at fruit set, fruit cell expansion and fruit filling stage). Fruits harvested from treatment combination H2S7 (homo-brassinolide @ 0.50 ppm applied three time of water deficit) were significantly superior in physico-chemical fruit quality characteristics viz. fruit size, weight, volume, TSS, sugars (total, reducing and non reducing) and ascorbic acid content as compared to other treatment combinations. The tree under treatment combination H6S7 i.e. methyl jasmonate spray at a concentration 20 ppm applied thrice at fruit set, fruit cell expansion and fruit filling stages recorded highest RWC of leaf, proline content, peroxidase activity, protease activity, chlorophyll content, photosynthetic rate, transpiration rate and stomatal conductance as compared to other treatment combination. Leaf nutrient content (N,P,K, Ca, Mg, Cu, Fe, Zn, Cu, and Mn) were recorded significantly higher under H2S7. It implies that homo-brassinolide spray at a concentration 0.50 ppm applied at fruit set, fruit cell expansion and fruit filling. The soil available nutrient (N, P and K) were also significantly higher under hormonal application H6 i.e. methyl jasmonate @ 20 ppm and S7 (at fruit set, fruit cell expansion and fruit filling stage) stage of application as compare to the control (water spray). In concern to yield and yield efficiency, significantly higher values were recorded under treatment combination H2S7. On the basis of results obtained in the present investigation, it has been concluded that treatment combination H2S7 i.e. homo-brassinolide spray at a concentration 0.50 ppm applied during periods of water deficit coinciding with fruit set, fruit cell expansion and fruit filling stages was found to be the best treatment as it resulted in significantly higher plant morphophysiological parameters, flowering parameters, fruit physico-chemical parameters, leaf nutritional parameters, yield and yield efficiency parameters was concerned. This treatment combination was closely followed H6S7 (methyl jasmonate @ 20 ppm applied thrice fruit set, fruit cell expansion and fruit filling stages) for most of the plant parameters studied.