Effects of Paclobutrazol on fruit yield and physico-chemical characteristics of mango Cvs. Dashehari, Langra, Chausa and Fazri
Abstract
Paclobutrazol is triazoles derivatives [(2 RS, 3RS)-1-(4-Chloropheny)-4, 4-dimethyl-2- (1, 2, 4 triazole-1-yl)] Pentane-3-ethanol. It is taken up of xylem and translocated acropetally to subapical meristem. Paclobutrazol is metabolized in plant in 10-15 days but persists in soil generally for more than one year Pactbutrazol was applied on a basic trunk drench (1.0 g/m, 0.5 g/mtree canopy diameter) in 21-22 year old mango tree Paclobutrazol treatment induced early ripening, reduced fruit sized when applied continuously for more than one year. However that quality was better in terms of higher TSS, total sugar, and β-carotene and Ascorbic aid.
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Introduction
Mango (Mangifera Indica L.)is the most important fruit crop of India. The production scenario of different fruits in India indicates that all the fruits occupied 6,480 thousand ha area with 92,846 thousand MTproduction and 14.3 MT/ha productivity during 2016-17. The total allocation to the fruits in the country has been increased from 6,235 to 6,480 thousand ha over the previous year, while the total production of fruits has also been increased from 89,512 to 92,846 thousand MT. The area and production of mango has been almost continuously increases over the years. The area under mango cultivation was 1077.6 thousand ha during 1991-92 which reaches up to 2516 thousand ha in 2013-14 and recorded 2262.8 thousand ha in 2016-17. However, the production has been fluctuating drastically. During 1991-92, the total production was 8,715.6 thousand MTwhich was increased up to 13,997 thousand MT in 2007-08. During 2008-09 the production was declined from 13997 thousand MT to 12,750 thousand MT. From 2009-10 there is continuous increase in the mango production (15,026.7 thousand MT) to 2016-17 (19,686.9 thousand MT). A total 109.99 % increase in area under mango cultivation has been recorded from 1991-92 to 2014-15 while, 125.88 % increase in production was recorded during the same period. However, productivity has been fluctuating drastically from 1991-92 to 2014-15. The productivity of 8.1 MT/ha was recorded during 1991-12 whereas, it was declined up to 5.5 MT/ha in 2008-09 and again increased up to 8.5 MT/ha in 2014-15 and reached up to maximum productivity of 8.7 MT/ha in 2016-17. There was overall increase of 7.41 % in productivity of mango from 1991-92 to 2014-15. In 2017, global mango production amounted to about 50.65 million metric tons. In India it is grown on an area of 2.516 million hectares with annual production of 18.431 million tonne having productivity of 7.3 metric tonne per hectare Anonymous (2017).
Although, alternate bearing is a major problems in mango production and its means "a condition at which high or optimum fruit production in on year or higher and certain year bear little or no fruit (off year), but growth regulators such as cultar reported to be effective on inducing flowering mango off year (Sinde et al.,2000). Paclobutrazol increased photosynthesis activity in apple (16%) (Kirn et al., 1990: Steffens, et al., 1990). Pecan (7.54%) (Wood 1984: Deyton, et al., 1991). Citrus (Deng et al, 1990). It also increased chlorophyll content in apple (Steffens, et al, 1983, 1984; Steffens and Wang, 1984, Wang et al, 1985, San Wavini et al, 1986; Kwon and Lee, 1986; Kim et al, 1990; Hao, et al, 1991, Pear (Bonomo and Neri, 1986), Peach (Coston, 1986; Choi et al, 1988), Strawberry (Archibold and Houtz, 1988), Grape (Shaltout et al., 1988), Banana (El-Qtmani et al, 1992) and Citrus (Deng et al., 1990). Paclobutrazol did not affect Sugar, pH, Colors or Glucose, Fructose ratio in Grape (Zoeckleni et al., 1991), Amino Cyclopropane, Carboxylic Acid, Ethylene, Respiration Sorbitol, Fructose, Glucose, Sucrose and Malic Acid in Apple (Wang and Steffen's, 1987). Paclobutrazol reduced sugar concentration in Apple (Green and Murray, 1983; Greene, 1986; Byun and Chang. 1986; Luo et al, 1989; Elfving et al., 1990; El-Khoreiby et al 1989; Forlanin and Cappola, 1992), Persimmon (Lee and Kim, 1991), TSS in Cherry (Looney and Mc Killar, 1987), acidity in Apricot (Mehta et al., 1990), and grape (Shaltout et al, 1988; Zoecklein et al. 1991, Reynold et al, 1992). Paclobutrazol [Paclobutrazol: (2RS, 3RS)-1-(4-chlorophenyl)-4, 4-dimethyl-2-(1, 2, 4-triazol-1-yl) pentan-3-ol.]
FIGURE 1: TOXICITY TABLE 1 EFFECTS PACLOBUTRAZOL TREATMENT POST HARVEST LIFE OF MANGO CVS. DASHERI, LANGRA, CHAUSA AND FAZRI (1998-99)
Reducing TSS Acidity Total Non reducing Ascorbic acid Treatment Sugar βcarotene (%) (%) Sugar (%) Sugar (%) (mg) (%)
Dashehari 0.22 1.42 36.79 Control 23.40 15.33 3.89 11.46 0.20 1.14 37.16 1.0g PBZ mtree 23.73 15.39 3.90 11.51 canopy diam.
Langra 1.38 Control 21.07 0.18 17.35 5.82 11.54 132.34 1.39 1.0g PBZ mtree 21.83 0.17 17.39 5.85 11.56 132.43 canopy diam.
Chausa 1.12 Control 21.66 0.26 17.47 5.34 12.14 38.86 1.13 1.0g PBZ mtree 21.71 0.25 17.51 5.36 13.23 39.35 canopy diam.
Fazri Control 17.57 0.31 13.64 5.66 7.98 1.15 12.91 1.0g PBZ mtree 17.81 0.29 13.69 5.67 8.05 1.16 13.21 canopy diam.
CD at 5% 0.20 0.84 0.19 0.12 0.40 0.76 0.51 Cultivar 0.14 0.59 0.13 0.86 0.28 0.54 0.36 Treatment 0.28 NS NS NS NS NS 0.72 Interction 140 120 100 TSS (%) 80 60 Acidity (%) 40 Total Sugar (%) 20 Reducing Sugar (%) 0 Non reducing Sugar (%) βcarotene Ascorbic acid (mg)
FIGURE 2: Effects Paclobutrazol treatment on Post Harvest life of Mango cvs. Dashehari, Langra, Chausa and Fazli. (1997-98).
TABLE 3 PACLOBUTRAZOL TREATMENT ON POST HARVEST LIFE OF MANGO CVS. DASHERI, LANGRA, CHAUSA AND FAZRI (1998-99)
Reducing TSS Acidity Total Non reducing Ascorbic acid Treatment Sugar βcarotene (%) (%) Sugar (%) Sugar (%) (mg) (%)
Dashehari Control 0.23 1.13 37.75 23.31 15.35 3.88 11.44 0.5g PBZ mtree 0.20 1.14 37.12 23.65 15.42 3.88 11.48 canopy diam.
Langra Control 1.37 21.11 0.18 17.37 5.81 11.54 132.32 0.5g PBZ/ mtree 1.38 21.78 0.17 17.41 5.83 11.54 132.37 canopy diam.
Chausa Control 1.11 21.64 0.26 17.48 5.33 12.13 38.97 0.5g PBZ/ mtree 1.13 21.81 0.25 17.54 5.36 13.15 39.33 canopy diam.
Fazri Control 17.54 0.31 13.64 5.67 8.46 1.14 22.89 0.5g PBZ/ mtree 17.75 0.29 13.73 5.65 8.04 1.16 13.17 canopy diam.
CD at 5% Cultivar 0.60 0.84 0.11 0.43 0.37 0.56 0.44 Treatment 0.43 0.59 0.79 0.30 0.26 0.40 0.31 Interction 0.86 NS NS 0.61 NS NS 0.63 140 120 100 80 TSS (%) 60 Acidity (%) 40 20 Total Sugar (%) 0 Reducing Sugar (%)
Non reducing Sugar (%) βcarotene Ascorbic acid (mg)
FIGURE 3: Effects Paclobutrazol treatment on Post Harvest life of Mango cvs. Dasheri, Langra, Chausa and Fazri (1998-99)
The acute oral LD50 of rats was 2000mg/kg (male), 1300mg/kg (female); for mice oral: 490mg/kg (male), 1,200mg/kg (female); for rabbit, the acute oral LD50: 840 mg/kg (male), 940 mg/kg (female). Rat and rabbit: acute percutaneous LD50> 1000mg/kg. For rat, acute inhalation has a LC50: 4.79mg/L (male) (4h), 3.13mg/L (female) (4h). It has certain irritant effect on the skin and eyes of the rat and rabbit. The no-action dosage for feeding rats of 2 years is 250 mg/kg; the no-action dosage for feeding dog of 1 year is 75 mg/kg; No mutagenicity effect. For rainbow trout, LC50:27.8mg/L (96h), carp LC5023.5mg/L (48h), and Daphnia LC50> 7900mg/L. Low toxicity to bees, LD50> 0.002mg/only.
