Multi-locational study on plant growth regulators to minimize pre-mature fruit drop and maximize postharvest quality of apples

Figures & data

Table 1. ANOVA summary for fruit productivity parameters, fruit quality indices and health-related compounds.

Factors	No. of flowers per branch		Fruit set (%)		Fruit drop (%)		Fruit size (cm^2)
	p-value	F	p-value	F	p-value	F	p-value	F
Loc x Treat	<.05	17.68	<.05	53.91	<.05	53.91	.2866	1.26
Loc x Var	<.05	3.83	<.05	0.47	<.05	0.47	<.05	5.57
Treat x Var	<.05	2.27	<.05	2.05	<.05	2.05	<.01	6.87
Loc x Treat x Var	<.01	2.37	<.01	2.10	<.05	2.10	<.05	1.94
CV	4.77		2.16		2.79		4.03
Factors	Fruit weight (g)		Yield per tree (kg)		Fruit firmness (kg/cm^2)		Fruit juice (%)
	p-value	F	p-value	F	p-value	F	p-value	F
Loc × Treat	<.01	3.20	<.01	44.50	<.01	25.76	<.05	3.30
Loc × Var	<.05	2.66	.9875	0.08	.3721	1.08	<.05	3.31
Treat × Var	<.01	4.20	<.01	37.85	<.01	26.76	<.05	45.06
Loc × Treat × Var	<.05	1.93	<.01	3.32	<.01	3.09	<.05	2.70
CV	9.51		1.28		4.72		3.47
Factors	Strife index (%)		pH		Titratable acidity (%)		Total soluble solids (%)
	p-value	F	p-value	F	p-value	F	p-value	F
Loc × Treat	<.05	2.68	<.05	2.80	<.01	5.05	.0560	2.22
Loc × Var	.1210	1.89	<.05	31.19	.3817	1.06	<.01	5.02
Treat × Var	<.01	26.28	<.05	4.62	<.01	6.44	<.01	11.29
Loc × Treat × Var	<.01	3.48	<.05	2.19	<.05	1.98	<.05	2.04
CV	6.36		3.58		10.78		8.78
Factors	Crude fiber (%)				Total ash content (%)
	p-value		F		p-value		F
Loc × Treat	<.01		5.88		<.01		5.41
Loc × Var	.1631		1.69		.08		2.17
Treat × Var	<.05		2.98		<.01		5.44
Loc × Treat × Var	<.01		3.68		<.05		1.85
CV	5.61				9.18
Factors	Vitamin C (mg/100g)		Total phenolics (mg gallic acid/100g FW)		Total flavonoids (mg/100g FW)		Antioxidant activity (µg/100g FW)
	p-value	F	p-value	F	p-value	F	p-value	F
Loc × Treat	.2223	1.41	<.01	9.32	<.01	5.16	<.05	3.28
Loc × Var	<.05	2.63	<.01	4.48	.0772	2.21	.2898	1.27
Treat × Var	<.01	15.01	<.01	16.22	<.01	5.13	<.01	19.02
Loc × Treat × Var	<.05	2.60	<.05	2.48	<.05	2.28	<.01	3.40
CV	6.26		6.33		5.53		7.61

Loc × Treat: Locations × Treatments; Loc × Var: Locations × Varieties; Treat × Var: Treatments × Varieities; Loc × Treat × Var: Locations × Treatments × Varieties; CV:.

Figure 1. Effect of different plant growth regulators on three apple varieties (‘Kashmir Amri’, ‘Red Delicious’, ‘Star Crimson’) grown at three different locations (Bagh, Dheerkot, Rawalakot) of Azad Jammu and Kashmir on (a) Number of flowers per branch (b) Fruit set (%) (c) Fruit drop (%). Treatments [1: Control; 2: NAA (25 ppm); 3: GA₃ (25 ppm); 4: 2, 4-D (25 ppm)].

Figure 2. Effect of different plant growth regulators on three apple varieties (‘Kashmir Amri’, ‘Red Delicious’, ‘Star Crimson’) grown at three different locations (Bagh, Dheerkot, Rawalakot) of Azad Jammu and Kashmir on (a) Fruit size (cm²) (b) Fruit weight (g) (c) Yield per tree (kg). Treatments [1: Control; 2: NAA (25 ppm); 3: GA₃ (25 ppm); 4: 2, 4-D (25 ppm)].

Figure 3. Effect of different plant growth regulators on three apple varieties (‘Kashmir Amri’, ‘Red Delicious’, ‘Star Crimson’) grown at three different locations (Bagh, Dheerkot, Rawalakot) of Azad Jammu and Kashmir on (a) Fruit firmness (kg/cm²) (b) Fruit juice (%). Treatments [1: Control; 2: NAA (25 ppm); 3: GA₃ (25 ppm); 4: 2, 4-D (25 ppm)].

Figure 4. Effect of different plant growth regulators on three apple varieties (‘Kashmir Amri’, ‘Red Delicious’, ‘Star Crimson’) grown at three different locations (Bagh, Dheerkot, Rawalakot) of Azad Jammu and Kashmir on (a) Strife index (%) (b) pH (c) Titratable acidity (%) (d) Total soluble solids (%) (e) Crude fiber (%) (f) Total ash content (%). Treatments [1: Control; 2: NAA (25 ppm); 3: GA₃ (25 ppm); 4: 2, 4-D (25 ppm)].

Figure 5. Effect of different plant growth regulators on three apple varieties (‘Kashmir Amri’, ‘Red Delicious’, ‘Star Crimson’) grown at three different locations (Bagh, Dheerkot, Rawalakot) of Azad Jammu and Kashmir on (a) Vitamin C (mg/100g) (b) Total phenolics (mg gallic acid/100g FW) (c) Total flavonoids (mg/100g FW) (d) Antioxidant activity (µg/100g FW). Treatments [1: Control; 2: NAA (25 ppm); 3: GA₃ (25 ppm); 4: 2, 4-D (25 ppm)].

Figure 6. Biplot of combined principal component analysis for fruit productivity parameters, fruit quality indices and health related compounds. Flo: Number of flowers per branch; Set: Fruit set; Dro: Fruit drop; Siz: Fruit size; Wei: Fruit weight; Yie: Yield per tree; Fir: Fruit firmness; Jui: Fruit juice; Stri: Strife index; TAA: Titratable acidity; TSS: Total soluble solids; Fib: Crude fiber; Ash: Total ash content; vit: Vitamin C; Phe: Total Phenolics; Flav: Total flavonoids; Anti: Antioxidant activity.

Figure 7. Correlation coefficient (r) representing the association among fruit productivity parameters, fruit quality indices and health related compounds. Flo: Number of flowers per branch; Set: Fruit set; Dro: Fruit drop; Siz: Fruit size; Wei: Fruit weight; Yie: Yield per tree; Fir: Fruit firmness; Jui: Fruit Juice; Stri: Strife index; TAA: Titratable acidity; TSS: Total soluble solids; Fib: Crude fiber; Ash: Total ash content; vit: Vitamin C; Phe: Total Phenolics; Flav: Total flavonoids; Anti: Antioxidant activity.

Figure 8. Mode of action of GA₃ for controlling pre-mature fruit drop (PFD) in apples.

Table 2. Mean maximum and mean minimum temperatures of the experimental sites during year 2022 and year 2023.

Bagh
Months	Year 2021		Year 2022
	Mean maximum temperature	Mean minimum temperature	Mean maximum temperature	Mean minimum temperature
January	27˚C	7˚C	24 °C	12 °C
February	22˚C	4˚C	20 °C	6 °C
March	25˚C	6˚C	24 °C	8 °C
April	33˚C	6˚C	38 °C	18 °C
May	34˚C	17˚C	45 °C	18 °C
June	40˚C	18˚C	46 °C	18 °C
July	34˚C	18˚C	40 °C	24 °C
August	31˚C	15˚C	38 °C	24 °C
September	29˚C	16˚C	37 °C	16 °C
October	28˚C	7˚C	32 °C	8 °C
November	22˚C	7˚C	32 °C	8 °C
December	20˚C	6˚C	30 °C	6 °C
Dheerkot
Months	Mean maximum temperature	Mean minimum temperature	Mean maximum temperature	Mean minimum temperature
January	24˚C	5˚C	23 °C	10 °C
February	19˚C	3˚C	19 °C	7 °C
March	23˚C	5˚C	23 °C	7 °C
April	30˚C	6˚C	36 °C	19 °C
May	31˚C	15˚C	38 °C	17 °C
June	45˚C	17˚C	39 °C	18 °C
July	32˚C	17˚C	38 °C	23 °C
August	29˚C	13˚C	36 °C	24 °C
September	27˚C	14˚C	35 °C	15 °C
October	27˚C	6˚C	30 °C	7 °C
November	21˚C	5˚C	30 °C	6 °C
December	19˚C	4˚C	28 °C	5 °C
Rawalakot
Months	Mean maximum temperature	Mean minimum temperature	Mean maximum temperature	Mean minimum temperature
January	13˚C	−5˚C	11 °C	−4 °C
February	16˚C	−2˚C	14 °C	−4 °C
March	21˚C	1˚C	24 °C	6 °C
April	26˚C	1˚C	30 °C	6 °C
May	31˚C	9˚C	35 °C	8 °C
June	34˚C	14˚C	34 °C	16 °C
July	33˚C	16˚C	35 °C	16 °C
August	27˚C	14˚C	34 °C	16 °C
September	27˚C	13˚C	32 °C	8 °C
October	25˚C	3˚C	30 °C	6 °C
November	19˚C	1˚C	20 °C	−4 °C
December	17˚C	−2˚C	12 °C	−12 °C

Data availability statement

The data have been given in manuscript. If any other details are needed, we will be happy to provide that.