Sweet Pepper Farming Strategies in Response to Climate Change: Enhancing Yield and Shelf Life through Planting Time and Cultivar Selection

Abstract

Climate change is an important concern worldwide. This huge change is causing a negative impact on crop productivity throughout the whole world and shows some drastic effects on sensitive crops including sweet pepper and other kinds of chilies. These stresses have a negative effect on vegetable growth, fruit quality, and fruit yield. Besides these stresses, accurate planting time is the utmost factor in increasing the crop potential and its productivity. Therefore, this study aimed to evaluate the optimal planting date and best-performing cultivar for sweet pepper to maximize crop productivity, growth, yield, and fruit shelf life under the impacts of climate change. The experiment was conducted in Multan, Pakistan (30° 25 N and 71° 30 E). In this experiment, four planting dates (10 January, 25 January, 10 February, and 25 February) with three cultivars (Ganga, Winner, and Savio) were grown with three replications (each year) during 2020 and 2021. Our findings showed that plant growth, fresh and dry biomass, yield, and yield attributes were statistically higher in earlier plantings, and lower in delayed planting. Regarding the cultivars in both years, ‘Winner’ performed better in all growth and yield parameters as compared to other growing cultivars. Lower weight loss and decay incidence were reported in ‘Winner’ cultivar. Additionally, ‘Winner’ cultivar showed a higher sensory score as compared to the other cultivar in both years. From the results, we conclude that the nursery of sweet pepper plants should be planted on the 25 January to attain higher crop productivity, and the cultivar ‘Winner’ showed promising effects so it should be planted for better yield.

1. Introduction

Sweet pepper (Capsicum annuum L.) ssp. is the third-largest cash crop which produces over 26 million tons of fruit in the nightshade family after tomatoes and potatoes and are bell-shaped, perennial vegetables with four or three leaves and colors including red-orange, green, yellow, purple-black, and brown [1,2]. In Pakistan, the planting area of pepper is about 62,000 hectares and the annual output is about 131,000 tons, which is decreasing continuously due to biotic and abiotic factors [3,4].

Abrupt changes in climate and environmental conditions cause different abiotic stresses and even a small environmental change can induce the expression or repression of hundreds of genes in plants, resulting in reduced crop yields [5,6]. High solar radiation, heat stress, drought, salinity, dry winds, hailstorms, and heavy metal toxicity are some of the major constraints affecting optimal productivity and nutritional quality of vegetables grown in the field [7,8]. The average temperatures are rising and are projected to rise by 2–4 °C in a couple of decades, a climate variation condition that could have a substantial effect on agriculture [9]. With this temperature increase, optimizing planting dates may be an environmentally friendly way of synchronizing plant growth stages with optimal temperatures [10]. Sweet peppers are sensitive to heat and bear less fruit at night-time heat. Pollen fertilization is strongly reduced under 15 °C and beyond 32 °C due to inefficient pollen development. Temperature is a vital environmental factor affecting the entire growth and development of plants from seed germination to seed maturity. Although sweet pepper is a warm-season crop, in hot summer, when the temperature exceeds 35 °C, the yield of pepper will drop significantly. Higher temperatures negatively affect the postharvest life of fruit by making it susceptible to moisture loss and other physiological problems, ultimately dropping the customer acceptance of fruits in the market.

Intercropping and crop rotation, when strategically aligned with planting time, can significantly increase yield by optimizing soil health and nutrient availability. Proper timing of intercropping maximizes biodiversity and pest control, while well-timed crop rotation prevents soil nutrient depletion and disrupts pest and disease cycles, leading to healthier, more productive plants [11,12]. In very few studies has the sowing date been reported to affect the growth and yield of bell peppers [13]. The results showed that the growth and yield of green peppers were improved at the appropriate planting date, and the fruit could be obtained for a longer period. The right planning time can lead to good fruit quality and high yields, while inappropriate planting dates can lead to poor fruit quality and low yields. Early sowing and later planting yield better yields [14]. Planting time has a significant impact on crop production due to changes in climate (temperature changes, frequency, and precipitation), which are closely related to crop phenology [15]. The optimal planting period for sweet pepper production determines the time when crops are at their maximum potential, when resources are being used efficiently, and the reduction of crop competition with weeds and pests, which are the key to increasing sweet pepper production. A good crop management strategy also requires the preparation of a planting window that is accurate for a particular crop hybrid and a particular location so that better crop management can be implemented. Ref. [16] optimized sowing dates and cultivars of sweet pepper seedlings in West Bengal, India, and found that Mekong cultivar sowing on 15 December showed the maximum growth and yield (no. of fruits and fruit weight). Ref. [17] observed that bell pepper sown on 1 October showed maximum growth, but the maximum yield was observed on 30 October planting in Gazipur, Bangladesh. Similarly, ref. [18] observed, in Ludhiana-India, that the maximum sweet pepper growth and production was obtained with the seedlings sowed on 30 October under black polythene mulch. In Rangpur-Bangladesh, ref. [19] observed that the best sowing date for sweet pepper cultivation was 15 November to attain maximum fruit and seed yield. In Rampur-Nepal, different sowing dates for the better production of sweet pepper were assessed by [20]. They observed that an early sowing date will enhance the sweet pepper production.

Despite the valuable insights provided by these studies, many have limitations such as focusing on a single genotype or a narrow range of environmental conditions. Furthermore, research specific to the Multan region, with its unique climatic challenges, remains limited. Methodological advancements in recent research include more precise planting dates and genotype selection. However, gaps still exist in understanding how these factors interact under local conditions. Our study aims to fill this gap by evaluating multiple genotypes and planting dates under Multan’s specific environmental conditions. By addressing these limitations and incorporating a broader range of variables, we aim to provide a more comprehensive understanding of optimal planting strategies for sweet peppers in this region. This approach not only builds on recent methodological advancements but also offers practical recommendations tailored to the Multan region. This enhances the significance of our findings. Therefore, the present study aimed to evaluate the optimal planting date and best-performing cultivar for sweet pepper to maximize crop productivity, growth, yield, and fruit shelf life under the impacts of climate change. This study aims to identify how different planting dates and different cultivars affect the growth parameters, biomass, yield attributes, weight loss, decay incidence, and sensory scores of sweet peppers across two years (2020 and 2021). We hypothesized that early planting dates might show better growth and yield as compared to the late planting dates. The goal is to provide recommendations on the most suitable planting date and cultivar for achieving higher crop productivity and shelf life in the face of climate-induced stresses in the agroecological area of Multan, Pakistan.

2. Material and Method

2.1. Plant Material and Area of Cultivation

The sweet pepper cultivars Winner, Ganga, Savio were cultivated during 2020–2021 in the open field at the Institute of Agronomy, Bahauddin Zakariya University, Multan-Pakistan (30°25 N, 71°30 E with 123.7 m sea elevation). The environment of this research area is semi-arid classified as Zone B according to the Köppen Climate Classification System. Weather data were obtained from the Pakistan Meteorological Department for Multan and shown in Figure 1.

The plants were grown following local production practices. The research experiment consisted of planting dates and cultivars in which transplanting dates were kept as the main plot factor and cultivars used as sub-plot factors. The treatment for the experiment were arranged according to a randomized complete block design (RCBD) with three replications. The planting dates for the experiment were 10 January, 25 January, 10 February, 25 February.

For sowing, seeds were sown in a nursery at the end of November for different transplanting dates; seeds were bought from the seed vender, and seedlings were raised in sowing trays having a media of peatmoss + silt (1:1 v/v). The condition of the growing medium was kept moist and shady until germination. Trays were irrigated daily if the weather was dry and hot. After 3 weeks, nitrogen was provided in the form of urea (0.1%) and six-week-old seedlings were transplanted in the field for both years.

The soil was clay loam with pH 8 and having a water-holding capacity of 45–56%. For land preparation, the land was plowed, planked, and leveled. Further, the ridges were made with the help of a ridger. The net plot size for this experiment was 1.8 m × 5 m with 45 cm within rows and 60 cm between the rows. Phosphorus was applied at a rate of 75 kg/ha and potassium at a rate of 60 kg/ha during the preparation of the land. Two doses of nitrogen, i.e., urea, 125 kg/ha, were applied to the crop; the 1st dose at the time of field preparation and the 2nd dose at the flowering stage.

To avoid any fungal infection and other diseases, seedlings were treated with fungicide before transplanting. Seedlings were placed at the top of ridges and water was applied to the field after transplanting. The source of water was a tube well and furrow irrigations were applied according to requirements and weather conditions. Other agronomic practices like weeding were performed as needed. To ensure the crop was free from insect pests and disease, IPM (integrated pest management practices) were followed. When the crop reached its physiological maturity and attained full-size shape and color, it was ready to harvest because the walls of the sweet pepper were very thick and fleshy at this time. A two-finger method was used for the picking of sweet peppers (grasping the fruit in the hand with the thumb and forefinger and pressing against the stem); due to this method, mature peppers will snap off easily from the plant.

2.2. Growth Attributes

For these research trials, ten plants were randomly selected from each replication of each sowing date. Given that there are three replications per sowing date, this results in a total of 30 plants for each sowing date being used for analysis. Stem diameter, number of leaves per plant, average canopy diameter, stem height, and chlorophyll content were measured before harvesting on the same day. For biomass analysis, destructive sampling of the same plants from each plot was performed. Afterward, the plants were washed to remove soil, and the leaves, roots, and stems were used for fresh and dry weight determination. Fresh weight was measured with a weighing balance. For dry weight, samples were kept in the oven at 65 °C for 48 h; after drying, samples were removed from the oven, and the dry weight of the leaves, roots, stems, and fruit were determined.

2.3. Yield Attributes

For yield parameters, the tagged plants were also used for yield determination. The fresh weight, length, and diameter of the fruits were measured. Subsequently, the fruits were dried following the previously described method to determine their dry weight. To calculate the total fruit yield, the weights from all harvests were summed to obtain the fresh weight per plant. The total number of fruits per plant was determined by adding up the number of fruits from each harvest.

2.4. Fruits’ Postharvest Attributes

For the determination of the fruits’ postharvest attributes, ten fruits from each experimental unit were stored for 9 days at room temperature (20 ± 2 °C). Physiological weight loss, decay incidence, and sensory scores (color, texture, freshness, and overall acceptability) were measured on 3-day intervals. Sensory scores were measured based on like and dislike by using a 9-point hedonic scale [21].

2.5. Statistical Analysis

The data analysis was conducted using Statistix 8.1 software (Tallahassee, FL, USA). An analysis of variance (ANOVA) was utilized to determine the overall significance of the results, and the means were compared using the Tukey-Kramer honestly significance difference (HSD) test at a 5% significance level. Pearson’s correlation matrix analysis was performed using Microsoft Excel-365.

3. Results

Throughout both years of the experimental study, crop growth and performance were normal. There were no significant issues related to weeds, diseases, pests, water or nutrient stress observed during the study period.

3.1. Growth Attributes

The effect of planting dates and varieties on stem height, average canopy diameter, number of leaves, and SPAD on sweet pepper plants were found to be statistically significant. The maximum stem height (48.58 cm), average canopy diameter (43.23 cm), number of leaves per plant (250.3), and SPAD (46.67) were found with planting date 2 (25 January) with the variety ‘Winner’ in year 2 (

Table 1. Growth parameters of sweet pepper cultivars affected by different planting dates in the years 2020 and 2021 at Multan, Pakistan.

Planting Dates (PD)	Varieties (VAR)	Year 1				Year 2
		Stem Height (cm)	Avg. Canopy Diameter (cm)	No. of Leaves/Plant	SPAD	Stem Height (cm)	Avg. Canopy Diameter (cm)	No. of Leaves/Plant	SPAD
10 January	Ganga	34.950 de	34.792 c	149.33 g	34.833 e	36.027 d	33.408 d	147.00 d	33.967 d
	Winner	39.411 b	35.768 c	202.33 d	42.333 ab	40.552 b	36.658 c	204.33 abc	43.333 ab
	Savio	33.265 ef	33.331 d	140.67 h	36.333 de	32.219 e	32.498 de	138.67 d	34.667 d
25 January	Ganga	37.234 c	38.544 b	221.33 c	41.333 abc	36.421 cd	37.486 c	185.67 bcd	40.333 bc
	Winner	47.425 a	42.081 a	248.00 a	45.667 a	48.587 a	43.233 a	250.33 a	46.667 a
	Savio	37.614 bc	38.344 b	181.67 e	35.667 de	36.416 cd	37.402 c	179.67 cd	34.667 d
10 February	Ganga	32.318 fg	32.383 d	163.67 f	35.333 e	31.210 ef	31.677 e	162.33 cd	34.333 d
	Winner	37.600 bc	37.679 b	208.00 d	42.333 ab	38.251 c	38.698 b	210.67 abc	43.667 ab
	Savio	31.023 g	30.213 e	141.67 h	35.667 de	29.697 f	29.381 f	140.33 d	34.333 d
25 February	Ganga	31.454 fg	30.565 e	169.33 f	34 e	30.617 ef	29.657 f	167.67 cd	33 d
	Winner	35.541 cd	35.371 c	230.33 b	40 bcd	36.358 cd	36.405 c	232.67 ab	41.333 b
	Savio	31.549 fg	29.844 e	155.33 g	37 cde	30.259 ef	28.807 f	153.33 d	36 cd
PD	F-Ratio	224.19	660.16	1120.37	11.65	260.41	730.43	10.42	10.34
	p-Value	0.000 ***	0.000 ***	0.000 ***	0.000 ***	0.000 ***	0.000 ***	0.000 ***	0.000 ***
VAR	F-Ratio	316.61	490.94	3219.27	69.90	567.52	1139.52	60.10	115.94
	p-Value	0.000 ***	0.000 ***	0.000 ***	0.000 ***	0.000 ***	0.000 ***	0.000 ***	0.000 ***
PD × VAR	F-Ratio	14.98	30.22	48.76	5.40	21.83	31.67	0.25	4.53
	p-Value	0.000 ***	0.000 ***	0.000 ***	0.002 **	0.000 ***	0.000 ***	0.95 ns	0.004 **

Means sharing different letter(s) within columns are statistically significant at p < 0.05 according to Tukey-Kramer HSD. (p < 0.001 (***), p < 0.01 (**), ns = not significant when p > 0.05).

). Moreover, the minimum stem height and average canopy diameter were observed on the 3rd planting date with ‘Savio’ (29.69 cm and 29.38 cm, respectively). However, the minimum number of leaves (138.67) and SPAD (33) were also observed in ‘Savio’ and ‘Ganga’ during planting dates 1 and 4 (10 January and 25 February, respectively) (Table 1).

The effect of planting dates and plant varieties on fresh biomass accumulation in sweet pepper plants were found to be statistically significant. During year 2, the values of the fresh weight of leaf (250.44 g), root (33.44 g), and stem (262.26 g) were significantly higher for planting date 2 (25 January) with the variety ‘Winner’ as compared to the other planting dates (

Table 2. Fresh biomass of sweet pepper cultivars affected by different planting dates in the years 2020 and 2021 at Multan, Pakistan.

Planting Dates (PD)	Varieties (VAR)	Year 1				Year 2
		Leaf Fresh Weight (g)	Stem Fresh Weight (g)	Root Fresh Weight (g)	Total Fresh Biomass ton/ha	Leaf Fresh Weight (g)	Stem Fresh Weight (g)	Root Fresh Weight (g)	Total Fresh Biomass ton/ha
10 January	Ganga	133.07 j	172.55 ef	14.100 h	12.789 f	131.73 i	171.41 cd	13.047 fg	12.648 c
	Winner	226.31 b	239.14 ab	27.653 b	19.724 ab	228.32 b	240.67 ab	28.547 b	19.902 ab
	Savio	150.71 g	173.77 def	13.423 h	13.51 ef	148.66 g	172.91 bcd	12.543 g	13.365 c
25 January	Ganga	114.92 k	235.00 abc	18.137 e	14.723 def	113.77 j	233.46 abc	17.400 d	14.585 c
	Winner	248.59 a	261.44 a	32.657 a	21.708 a	250.44 a	262.62 a	33.443 a	21.860 a
	Savio	169.14 e	225.89 a-d	18.437 e	16.539 cd	167.82 e	191.73 bcd	17.323 d	15.075 c
10 February	Ganga	139.48 i	174.27 def	16.660 f	13.216 ief	138.42 h	173.08 bcd	15.703 e	13.088 c
	Winner	222.33 c	211.38 a-e	26.300 c	18.400 bc	224.84 c	212.55 abcd	27.407 b	18.592 b
	Savio	141.97 h	184.16 c-f	15.410 g	13.66 ef	140.07 h	183.25 bcd	14.650 ef	13.519 c
25 February	Ganga	160.81 f	158.73 f	13.803 h	13.33 ef	159.99 f	157.99 d	12.613 g	13.223 c
	Winner	205.04 d	148.15 f	22.040 d	15.009 de	207.41 d	148.98 d	23.287 c	15.187 c
	Savio	149.01 g	189.85 b-f	14.247 gh	14.124 fef	147.66 g	189.04 bcd	14.507 ef	14.048 c
PD	F-Ratio	254.25	28.63	378.53	41.78	137.33	11.56	198.06	17.51
	p-Value	0.000 ***	0.000 ***	0.000 ***	0.000 ***	0.000 ***	0.000 ***	0.000 ***	0.000 ***
VAR	F-Ratio	44,280.8	9.23	3129.43	192.98	25,723.0	7.62	2450.15	131.99
	p-Value	0.000 ***	0.001 **	0.000 ***	0.000 ***	0.000 ***	0.003 **	0.000 ***	0.000 ***
PD × VAR	F-Ratio	1892.33	5.42	55.88	12.58	1015.19	4.30	35.31	7.92
	p-Value	0.000 ***	0.002 **	0.000 ***	0.000 ***	0.000 ***	0.005 **	0.000 ***	0.000 ***

Means sharing different letter(s) within columns are statistically significant at p < 0.05 according to Tukey-Kramer HSD. (p < 0.001 (***), p < 0.01 (**) when p > 0.05).

). A significantly lower root fresh weight (12.54) was observed from planting date 1 (10 January) with the variety ‘Savio’, and for stem (11.38) found in the variety ‘Winner’ and leaf (38.42 g) found in the variety ‘Ganga’ with planting date 3 (10 February).

The effect of planting dates and plant varieties on dry biomass accumulation in sweet pepper plants were found to be statistically significant. During year 2, the values of dry weight of leaf (27.16 g), root (16.19 g), and stem (43.10 g) were significantly higher with planting date 2 (25 January) with the variety ‘Winner’ as compared to the other planting dates (

Table 3. Dry biomass of sweet pepper cultivars affected by different planting dates in the years 2020 and 2021 at Multan, Pakistan.

Planting Dates (PD)	Varieties (VAR)	Year 1				Year 2
		Leaf Dry Weight (g)	Stem Dry Weight (g)	Root Dry Weight (g)	Total Dry Biomass ton/ha	Leaf Dry Weight (g)	Stem Dry Weight (g)	Root Dry Weight (g)	Total Dry Biomass ton/ha
10 January	Ganga	21.283 bc	22.687 de	3.582 h	1.902 e	20.657 d	21.663 de	2.494 g	1.792 e
	Winner	25.117 a	35.733 b	12.230 b	2.923 b	26.603 ab	36.733 b	13.673 b	3.080 b
	Savio	14.949 g	22.915 de	7.729 de	1.823 ef	14.362 fg	22.101 de	6.669 cde	1.725 e
25 January	Ganga	18.810 de	32.655 bc	8.499 d	2.398 cd	17.369 e	31.243 c	7.688 cd	2.252 d
	Winner	26.448 a	41.851 a	14.812 a	3.324 a	27.169 a	43.104 a	16.193 a	3.458 a
	Savio	17.098 ef	30.917 bc	9.337 cd	2.294 d	15.808 ef	29.543 c	8.437 c	2.151 d
10 February	Ganga	17.850 e	22.233 de	6.341 ef	1.857 e	16.213 ef	21.533 de	5.447 def	1.727 e
	Winner	22.028 b	30.260 bc	12.187 b	2.579 c	24.369 bc	30.301 c	13.457 b	2.725 c
	Savio	13.639 g	26.852 cd	6.090 jefg	1.863 e	12.412 g	26.400 cd	5.173 ef	1.759 e
25 February	Ganga	15.357 fg	19.437 e	4.436 gh	1.569 f	14.175 fg	17.921 e	3.208 fg	1.412 f
	Winner	20.058 cd	18.302 e	10.489 bc	1.953 e	22.487 cd	19.584 e	11.655 b	2.149 d
	Savio	14.972 g	22.980 de	5.897 fg	1.753 ef	13.850 fg	21.386 de	4.627 efg	1.594 ef
PD	F-Ratio	93.01	86.09	68.07	141.44	35.14	104.80	44.02	127.96
	p-Value	0.000 ***	0.000 ***	0.000 ***	0.000 ***	0.000 ***	0.000 ***	0.000 ***	0.000 ***
VAR	F-Ratio	560.65	44.76	390.64	256.60	463.60	91.14	416.63	452.92
	p-Value	0.000 ***	0.000 ***	0.000 ***	0.000 ***	0.000 ***	0.000 ***	0.000 ***	0.000 ***
PD × VAR	F-Ratio	20.21	13.88	7.60	14.59	7.19	16.03	4.52	10.95
	p-Value	0.000 ***	0.000 ***	0.000 ***	0.000 ***	0.000 ***	0.000 ***	0.004 **	0.000 ***

Means sharing different letter(s) within columns are statistically significant at p < 0.05 according to Tukey-Kramer HSD. (p < 0.001 (***), p < 0.01 (**) when p > 0.05).

). A significantly lower dry weight of root (2.49) was observed with planting date 1 with the variety ‘Ganga’ and for stem (17.92) with the variety ‘Ganga’ on planting date 4 and for leaf (12.41 g) with variety ‘Savio’ on planting date 3.

3.2. Yield Attributes

The effect of planting dates and plant varieties on the yield component of sweet pepper, which is the number of fruits, average fruit weight, fruit width, and fruit length, were found to be statistically significant. There was no significant difference between the two years. The maximum number of fruits (13.62), average fruit weight (32.47 g), and fruit width (42.80 mm) were found with planting date 2 (25 January) with the variety ‘Winner’ as compared to the other planting dates in year 2, and the maximum average fruit length (37.10 mm) was recorded from planting date 2 (25 January) with the variety ‘Winner’ during year 1 (

Table 4. The yield attributes of sweet pepper cultivars affected by different planting dates in the years 2020 and 2021 at Multan, Pakistan.

Planting Dates (PD)	Varieties (VAR)	Year 1					Year 2
		No of Fruits/Plant	Avg. Fruit Width (mm)	Avg. Fruit Length (mm)	Avg. Fruit Weight (g)	Yield ton/ha	No of Fruits/Plant	Avg. Fruit Width (mm)	Avg. Fruit Length (mm)	Avg. Fruit Weight (g)	Yield ton/ha
10 January	Ganga	5.98 de	33.76 fd	31.57 d	22.14 de	5.34 d	4.99 d	32.68 d	29.10 de	19.84 f	4.13 ef
	Winner	7.45 c	34.20 d	31.64 d	27.12 b	8.11 c	8.32 b	35.86 bc	33.36 bc	29.21 b	9.12 b
	Savio	4.31 gh	31.39 e	26.55 if	20.88 e	3.63 ef	3.57 ef	30.59 e	24.51 f	18.76 f	2.85 fg
25 January	Ganga	9.17 b	37.40 bc	35.03 b	26.94 bc	9.92 b	8.51 b	36.22 b	33.07 bc	24.78 de	9.11 b
	Winner	12.64 a	41.40 a	37.10 a	30.47 a	15.42 a	13.62 a	42.80 a	36.54 a	32.47 a	16.73 a
	Savio	7.03 cd	37.61 b	33.68 bc	24.41 cd	6.89 c	6.33 c	36.22 b	31.60 cd	22.37 e	5.59 de
10 February	Ganga	5.32 efg	33.42 d	28.69 e	22.08 fde	4.76 de	4.44 de	32.61 d	26.47 ef	19.62 f	3.99 ef
	Winner	6.9 cd	36.00 c	33.14 c	25.46 bc	7.08 c	8.03 b	37.18 b	34.88 ab	27.73 bc	7.96 bc
	Savio	4.52 fgh	33.14 d	27.65 ef	14.56 fg	2.64 fg	3.76 de	32.25 d	25.62 f	12.30 gh	1.77 g
25 February	Ganga	2.78 i	27.06 f	23.26 g	15.92 f	1.79 mg	1.92 g	25.95 f	21.13 g	13.94 g	1.30 g
	Winner	5.44 jef	33.22 d	27.83 ef	24.32 cd	5.30 d	6.55 c	34.64 c	27. 10 ef	26.67 cd	6.53 cd
	Savio	3.51 hi	28.13 f	23.24 g	12.57 g	1.79 g	2.39 fg	27.04 f	21.59 g	10.51 h	1.10 g
PD	F-Ratio	390.83	570.83	680.11	184.04	385.56	314.44	591.86	171.78	210.66	217.53
	p-Value	0.000 ***	0.000 ***	0.000 ***	0.000 ***	0.000 ***	0.000 ***	0.000 ***	0.000 ***	0.000 ***	0.000 ***
VAR	F-Ratio	255.18	207.44	270.34	280.58	331.21	509.19	647.40	175.33	778.16	393.87
	p-Value	0.000 ***	0.000 ***	0.000 ***	0.000 ***	0.000 ***	0.000 ***	0.000 ***	0.000 ***	0.000 ***	0.000 ***
PD × VAR	F-Ratio	19.35	19.41	21.00	13.25	16.63	11.94	20.69	7.46	16.20	12.91
	p-Value	0.000 ***	0.000 ***	0.000 ***	0.000 ***	0.000 ***	0.000 ***	0.000 ***	0.000 ***	0.000 ***	0.000 ***

Means sharing different letter(s) within columns are statistically significant at p < 0.05 according to Tukey-Kramer HSD. (p < 0.001 (***) when p > 0.05).

). Further, the yield component including the number of fruits (1.92), fruit width (25.95 mm), and fruit length (21.13 mm) showed the minimum effect from planting date 4 (25 February) with the variety ‘Ganga’ during year 2, and the minimum average fruit weight (10.51 g) was recorded from planting date 4 (25 February) with the variety ‘Savio’ as compared to the other planting dates.

3.3. Fruits’ Postharvest Attributes

The ‘Winner’ cultivar showed considerably lower weight loss and decay incidence as compared to the other cultivars in both years (

Table 5. The postharvest attributes of sweet pepper cultivars affected by different planting dates in the years 2020 and 2021 at Multan, Pakistan.

Planting Dates (PD)	Varieties (VAR)	Year 1					Year 2
		Fruit Weight Loss (%)	Fruit Decay (%)	Acceptability	Texture	Color	Fruit Weight Loss (%)	Fruit Decay (%)	Acceptability	Texture	Color
10 January	Ganga	12.9 de	25 ab	5.8 ab	6 ab	5.6 a	11.96 bc	23.33 ab	6.5 ab	6 ab	5.6 a
	Winner	12.31 e	21.66 b	6.3 a	6.6 a	6.3 a	11.53 c	20 b	7 a	6.3 a	6 a
	Savio	12.21 e	31.66 ab	5.9 ab	6 ab	6 a	11.63 c	28.22 ab	6 ab	6 ab	5.6 a
25 January	Ganga	14.54 b-e	30 ab	6 ab	6.3 a	5.6 a	13.84 abc	30 ab	6.5 ab	6.3 a	5.6 a
	Winner	12.66 de	25 ab	6.2 a	6.6 a	6 a	11.75 bc	28.33 ab	6.8 ab	6.3 a	6 a
	Savio	13.43 cde	35 ab	5.5 abc	6 ab	5.3 a	12.56 bc	33.33 ab	5.9 abc	5.6 ab	5.3 a
10 February	Ganga	15.18 a-d	30 ab	5.9 ab	6 ab	5.6 a	15.27 ab	33.33 ab	6.7 ab	6 ab	6 a
	Winner	14.33 cde	30 ab	6.1 ab	6.3 a	6 a	13.97 abc	30 ab	6.5 ab	6.3 a	6 a
	Savio	14.87 b-e	36.66 a	5.4 abc	5.3 ab	5.3 a	14.7 abc	33.33 ab	5.5 bc	5.6 ab	5.3 a
25 February	Ganga	17.71 a	31.66 ab	5.1 bc	5.3 ab	5 a	16.36 a	31.66 ab	5.6 bc	5.6 ab	4.6 a
	Winner	15.72 abc	30 ab	5.5 abc	5.6 ab	5.6 a	14.55 abc	30 ab	6.3 ab	5.6 ab	5.3 a
	Savio	17.12 ab	38.33 a	4.5 c	4.3 b	4.6 a	17.22 a	38.33 a	4.6 c	4.6 b	4.6 a
PD	F-Ratio	38.81	3.69	13.55	7.14	3.87	23.94	5.22	9.16	5.25	7.13
	p-Value	0.000 ***	0.027 *	0.000 ***	0.001 **	0.023 *	0.000 ***	0.007 **	0.000 ***	0.007 **	0.001 **
VAR	F-Ratio	6.42	9.82	12.87	6.59	4.58	4.60	3.85	22.14	6.02	4.42
	p-Value	0.006 **	0.000 ***	0.000 ***	0.005 **	0.021 *	0.021 *	0.036 *	0.000 ***	0.008 **	0.024 *
PD × VAR	F-Ratio	0.35	0.07	0.34	0.14	0.34	0.34	0.13	0.38	1.13	0.28
	p-Value	0.70 ns	0.92 ns	0.71 ns	0.86 ns	0.71 ns	0.71 ns	0.88 ns	0.68 ns	0.33 ns	0.75 ns

Means sharing different letter(s) within columns are statistically significant at p < 0.05 according to Tukey-Kramer HSD. (p < 0.001 (***), p < 0.01 (**), p < 0.05 (*), ns = not significant when p > 0.05).

). The 1st and 2nd planting dates showed considerably lower weight loss and decay incidence as compared to the 3rd and 4th in both years. Similarly, higher sensory scores were found in the ‘Winner’ cultivar as compared to the other cultivars as this cultivar retained higher sensory scores up to the 9th day of storage. There was a significant difference among the planting dates in sensory scores; higher sensory scores were noted on 25 January-planted sweet papers as compared to the other planting dates.

3.4. Correlation

Pearson’s correlation matrix explored relationships between various attributes across different planting dates (see

Table 6. Pearson’s correlation matrix for studied attributes in sweet pepper cultivars grown at different planting dates.

	SH	ACD	NLPP	LFW	LDW	SFW	SDW	RFW	RDW	FBM	DBM	NFPP	AFW	AFL	AFWT	YT	SP
SH	1
ACD	0.929 ***	1
NLPP	0.817 ***	0.821 ***	1
LFW	0.740 ***	0.610 ***	0.757 ***	1
LDW	0.875 ***	0.780 ***	0.786 ***	0.787 ***	1
SFW	0.783 ***	0.719 ***	0.544 **	0.453 *	0.591 ***	1
SDW	0.847 ***	0.771 ***	0.590 ***	0.561 ***	0.652 ***	0.972 ***	1
RFW	0.883 ***	0.795 ***	0.877 ***	0.905 ***	0.890 ***	0.705 ***	0.781 ***	1
RDW	0.840 ***	0.817 ***	0.859 ***	0.876 ***	0.787 ***	0.682 ***	0.757 ***	0.954 ***	1
FBM	0.892 ***	0.776 ***	0.787 ***	0.890 ***	0.829 ***	0.809 ***	0.866 ***	0.963 ***	0.930 ***	1
DBM	0.942 ***	0.866 ***	0.788 ***	0.779 ***	0.869 ***	0.871 ***	0.926 ***	0.945 ***	0.912 ***	0.962 ***	1
NFPP	0.953 ***	0.938 ***	0.804 ***	0.591 ***	0.798 ***	0.835 ***	0.882 ***	0.841 ***	0.810 ***	0.824 ***	0.927 ***	1
AFW	0.865 ***	0.925 ***	0.703 ***	0.515 ***	0.702 ***	0.741 ***	0.822 ***	0.762 ***	0.767 ***	0.727 ***	0.854 ***	0.944 ***	1
AFL	0.855 ***	0.925 ***	0.663 ***	0.473 **	0.749 ***	0.797 ***	0.841 ***	0.738 ***	0.717 ***	0.726 ***	0.865 ***	0.923 ***	0.956 ***	1
AFWT	0.885 ***	0.937 ***	0.825 ***	0.650 ***	0.870 ***	0.633 ***	0.695 ***	0.825 ***	0.834 ***	0.761 ***	0.862 ***	0.886 ***	0.864 ***	0.879 ***	1
YT	0.964 ***	0.936 ***	0.829 ***	0.620 ***	0.816 ***	0.821 ***	0.864 ***	0.851 ***	0.818 ***	0.836 ***	0.926 ***	0.993 ***	0.912 ***	0.892 ***	0.898 ***	1
SP	0.844 ***	0.792 ***	0.881 ***	0.773 ***	0.839 ***	0.734 ***	0.759 ***	0.936 ***	0.922 ***	0.893 ***	0.908 ***	0.849 ***	0.729 ***	0.723 ***	0.808 ***	0.858 ***	1

SH = stem height; ACD = average canopy diameter; NLPP = no. of leaves per plant; LFW = leaf fresh weight; LDW = leaf dry weight; SFW = stem fresh weight; SDW = stem dry weight; RFW = root fresh weight; RDW = root dry weight; FBM = fresh biomass; DBM = dry biomass; NFPP = no. of fruits per plant; AFW = average fruit width; AFL = average fruit length; AFWT = average fruit weight; YT = yield ton/ha; SP = SPAD. (p < 0.001 (***), p < 0.01 (**), p < 0.05 (*) when p > 0.05).

). The correlation coefficient ≥ 0.9 is considered as significantly correlated. The analysis revealed significant positive correlations between certain variables: for instance, stem height and canopy diameter were notably associated with each other. Additionally, there was a positive correlation observed between leaf fresh weight and root fresh weight. Notably, yield showed significant positive correlations with stem height, average canopy diameter, and dry biomass, suggesting these attributes play crucial roles in determining crop productivity. Furthermore, SPAD values were found to correlate positively with root fresh weight, root dry weight, and dry biomass, indicating a potential indicator of plant health and nutrient status (Table 6). These findings underscore the inter-relationships among growth parameters and productivity metrics, highlighting the importance of optimizing these factors for enhancing sweet pepper yield and quality. The dry biomass was significantly and positively correlated with stem height, no. of fruits per plant, stem dry weight, root fresh and dry weight, fresh biomass, and yield.

4. Discussion

Climate change is one of the major concerns for crop productivity. Vegetable crops have some natural ability and adaptive mechanisms to cope with the negative effects of climate change, but these abilities may not be sufficient to cope with the swift climate changes [7]. Our research evaluated sweet pepper performance in a semi-arid environment using different planting dates and cultivars. The findings of growth, biomass, and yield characteristics presented in Table 1, Table 2, Table 3 and Table 4 exhibit that different transplanting dates have significant effects on the growth and yield of sweet pepper cultivars during both years. Among planting dates, the early transplanting in both years gave the maximum values for growth parameters as well as yield attributes. Further, the crop stages at specific temperatures were affected by climate change and varieties. Similar findings have been reported by [22,23]. There could be several factors contributing to the growth of sweet pepper in the early plantings, including favorable environmental conditions that influenced growth (the length of the stem, number of leaves, and width of the plant) and biomass of the plant. Fresh and dry masses of the plant parts showed a similar trend when it came to the planting date effect. It has been demonstrated in research that early planting can give plants the opportunity for optimal growth and development [24]. Our findings also showed similar trends (Table 1 and Table 2), which depicted that sweet pepper seedlings planted early gave more growth attributes. Similar findings were observed by [17], which showed that sweet pepper sown early showed more growth attributes as compared to late sowing. Refs. [16,22] also observed that different transplanting dates affect the no. of leaves, leaf area, and canopy spread. During the crop period, the crop growth, which includes emergence, flowering, and fruiting, was markedly affected by the normal temperature. Different studies showed various effects of day and night temperature on crop life span [25]. Planting time and choice of variety are the most significant factors for crop yield, and the response among varieties could be different due to the surrounding environment and genetic makeup of these varieties [26]. Some studies were observed by other scientists in which early planting promotes vegetative growth and biomass due to controlled environmental conditions. Growth parameters such as plant height, stem diameter, and canopy diameter increased in earlier planting dates, and biomass (fresh and dry) showed a similar pattern in effect of planting dates (Table 2 and Table 3). The planting dates attain sufficient time for optimum growth and development when the plant is transplanted before and on the recommended time [21].

Concerning yield attributes, we found that the early sowing date showed a greater no. of fruits, fruit size, and fruit weight as compared to the late sowing dates (Table 4). The no. of fruits, fruit size, and weight were significantly correlated with plant growth attributes (Table 6), which indicated that the better the plant growth, the better the yield. Similar results were observed by [22], which depicted that a favorable transplanting date is highly efficient in producing and translocating assimilates to the sink and accelerating fruit formation. Compared to [22], higher temperatures reduced flower set and yields [27]. It was also discovered that the failure of fruit set is linked to climatic factors such as high temperatures and low humidity, in addition to genetic variation, as noted by [28]. Based on the studies of [29], a wide variation in the yield of fruit at different transplantations is mainly caused by genotypic variation and climatic conditions. Additionally, ref. [30] reported that late transplanting dates reduced fruiting, which might be due to high average temperature which led to a lower fruit set that reduced fruit yield. Our results also depicted that late transplanting showed a decrement in fruit yield. The fruit yield also decreased with the decreasing no. of leaves as shown in Table 6 [16]. According to [31], this might be a result of the prevailing environmental conditions for flowering as well as fruit setting. The study [32] also concluded that high temperatures below 35 °C result in less pollination and fruit setting. A sweet pepper’s production is more affected by nighttime air temperature than by the daytime air temperature. When the night air temperature reaches a temperature of more than 32 °C, the flowers drop and do not set fruit.

Reduced weight loss and decay incidence in early planting dates might be due to the temperature effect. Crops sown later could be affected by higher temperatures, which increase respiration, and moisture loss, and favor microbial infestation in harvested fruits. Similarly, in our findings, late planting dates showed fewer shelf-life days as compared to early planting dates (Table 5). The second possible reason for lower weight loss in larger fruits might be because of their size. The smaller fruits exhibited larger decreases in surface area and higher water loss rates compared to larger fruits, with these rates declining as fruits matured. Immature fruits had the highest surface area/fresh weight ratios and water loss rates, while mature fruits showed lower permeance to water vapor [33]. Crucifer plant’s sensory qualities are influenced by environmental circumstances such as growing location and planting timing. Turnip sensory qualities such as aroma, texture, and taste are affected by growing temperature and precipitation at different locations [34]. Researchers reported that the planting date at the same site affects the sensory characteristics of cabbage [35]. The sensory and phytochemical contents of broccoli florets can be influenced by temperature and light. High northern latitude growing conditions are characterized by a long photoperiod and cold temperature, resulting in the production of larger flower buds and florets with a sweeter flavor and less color hue [36]. Sensory scores were improved by early planting in all cultivars, and the ‘Winner’ cultivar was the most effective among the others. This was due to a higher yield and quality attributes such as fruit length, width, weight, and color, which improved the sensory scores and retained it for a longer time compared to the cultivars that exhibited lower yield and quality attributes [37]. Pearson’s correlation depicted that all the studied attributes during the study were correlated with each other (Table 6). The correlation indicated that growth and yield attributes are positively correlated. The plants showed more growth (stem height, canopy diameter, etc.), had more no. of fruits, and greater fruit size and weight which led to a better yield (Table 6). Therefore, novel locally adopted varieties should be introduced. Besides this, the accurate alteration in planting time for transplanting the sweet pepper crop is a key factor to lessen the bad impact of the changing environment in different areas of Punjab, Pakistan.

5. Conclusions

The experiment demonstrated that the ‘Winner’ cultivar significantly outperformed other cultivars in terms of growth, development, and yield of sweet pepper. Our findings clearly indicate that the optimal planting date is 25 January, as early planting dates yielded superior results compared to later dates. This study highlights the critical impact of planting time and variety selection on both vegetative and reproductive phases of sweet pepper, with consistent results observed over the two years of the study. The methodological advancements in this research, including precise timing of planting and selection of high-performing cultivars, provide valuable insights for maximizing crop productivity under the pressures of climate change. The ‘Winner’ cultivar exhibited the greatest yield, postharvest life, and overall crop performance when planted on 25 January, validating the importance of early planting. For the environmental conditions of Multan, Punjab (30°25 N and 71°30 E), it is recommended that a forty-day-old nursery of sweet pepper be transplanted on 25 January to achieve optimal growth, higher productivity, and quality fruits. These findings underscore the necessity of further research aimed at mitigating the adverse effects of climate change on crop productivity. The superior methodology employed in this study can serve as a foundation for future research, guiding agricultural practices to enhance crop resilience and yield in the face of climatic challenges.