Climatic and Altitudinal Variation in Physicochemical Properties of Citrus sinensis in India

Abstract

C. sinensis (L.) Osbeck is grown in large-scale, in-home gardens of traditional agroforestry systems in the Garhwal Himalaya. The present investigation of C. sinensis was conducted on the basis of twenty-six populations in different home gardens located in different geographical variables. The aim was to understand variations in physicochemical properties, viz., fruit weight, fruit length, fruit width, peel thickness, peel weight, juice sacks, juice weight, seeds/fruits, rudimentary seeds/fruits, seed weight, total soluble solids, citric acid, ascorbic acid and sugar content. The results of the study revealed that the physicochemical properties of C. sinensis were significantly varied among the populations. The fruit weight was the most variable among the morphological characteristics, and vitamin C among the nutritive parameters. The average fruit weight varied from 96.64 to 296.86 g/fruit. The other study traits were found to oscillate between 7.73 and 12.76 °Brix (total soluble solids); 3.04 and 5.96% (citric acid); 31.45 and 86.45 mg/g⁻¹ (vitamin C) and 4.65 and 9.27% soluble sugar. Geographical variables (altitude, latitude and longitude, temperature and rainfall) have influenced the physicochemical parameters of C. sinensis significantly. Amongst the physicochemical properties, fruit weight and vitamin C were the most variable parameters and could be used for the improvement of C. sinensis. These variations in the C. sinensis population have enabled great advances in better understanding the variability in the physicochemical properties of fruit and response to biotic and abiotic stresses.

1. Introduction

Fruits play a very significant role in nutritional security, generation of employment and the overall economic growth of the country. The importance of fruits is primarily considered in the context of energy and nutritive value. Fruits are a suitable diet for people of all age groups. They are a good source of dietary fiber, and fiber intake reduces the risk of cardiovascular disease and obesity. Fruits are consumed raw or processed and provide vitamins, minerals and different phytochemicals, which are a rich source of antioxidants, phytoestrogens, and anti-inflammatory agents. [1]

In fruit production, India ranks second after China, sharing about 12% of the world’s fruit production. Five fruits (banana, mango, citrus, papaya and guava) comprise more than 75% of the total fruit production in India [2]. Fruit has various natures and multifold nutritional and medicinal values. It is primarily valued for being either eaten alone as fresh fruit or processed into juice, or added to dishes and beverages (lemon, lime etc.). C. sinensis fruits have a prominent place among the popular and intensively grown and possess wider adaptability to different agro-climatic conditions. They grow equally in tropical and sub-tropical regions, including some favorable parts of the temperate regions of the world [2].

India is the fourth largest C. sinensis-producing country in the world, contributing 6.0% of the world’s total production [3], and in terms of cultivation area, C. sinensis is the third largest fruit industry after banana and mango. Over the last 30 years, the area and production of Citrus has increased at the rate of 11% and 9%, respectively, which indicated the expansion of the C. sinensis-based industry.

In India, citrus fruits are primarily grown in Maharashtra, Andhra Pradesh, Punjab, Karnataka, Uttarakhand and Bihar. The total area of sweet orange cultivation in India is 187 thousand hectares with a production of 3266 thousand MT during the period 2018–2019 [2]. C. sinensis L. (locally known as Malta) belongs to the family Rutaceae and is grown successfully in home gardens and bunds of agricultural fields in the Garhwal Himalaya, Uttarakhand, India. C. sinensis is generally grown from seeds and planted in home gardens. Home gardens in the Garhwal Himalaya have been used from time immemorial and are rich sources of biodiversity conservation. In home gardens, local farmers usually grow multi-storied cropping patterns on small pieces of land for the fulfillment of their daily needs, i.e., fruits, vegetables and spaces, etc. A study was conducted to evaluate the home gardens of the Garhwal Himalaya region and reported a total of 46 species in home gardens. Amongst the 46 species, 27 were agricultural crops and 15 were fruit crops and multipurpose trees. The density of C. sinensis was reported to be 106–313 trees/ha with other associated tree species such as Grewia optiva, Citrus limon, etc. [4].

Amongst the different citrus species grown in the different agroclimatic zones of tropical to temperate regions of the Garhwal Himalaya, Uttarakhand, C. sinensis was the dominant with the highest production. Due to its sweet–sour taste, charming flavor and refreshing juice, it is consumed fresh [5].

C. sinensis fruit is consumed within a short period of time due to its perishability. The fruit is harvested in the winter season [6] and is used to make different value-added products, i.e., juice, jam, jelly, squash and candy. Therefore, with multiple outcome products, Citrus is considered a cash crop [7]. Regarding total soluble solids (10^oBx), one hundred grams of C. sinensis ready-to-serve (RTS) fruit contains 88.4 g water, 0.6 g protein, 10.5 g carbohydrates, 0.12 g fibers, 0.3 g ash and has 0.41% acidity [8]. Its peel is used to extract the essential oil which has great therapeutic and various cosmetic values. Ukaoma et al. [9] reported that the fruit peel of C. sinensis can be used to produce bio-fuel which is ecologically as well as economically suitable and provides employment opportunities for local people. Due to its uses and health benefits, the state agriculture and watershed divisions of Uttarakhand make offers and promote local marginal farming for C. sinensis growth on slope areas under the horticulture development program [10], but the management practices are improper and losing their production [11].

Home gardens usually grow a variety of species in small areas such as Grewia optiva, Celtis australis, Pyrus pashia, Artrocarpus heterophyllus, Mangifera indica, Psidium guajava, Juglans regia, Morus alba, Ficus spp. and Quercus leucotrichophora, etc., including C. sinensis. Vegetables such as onion, chilies, brinjal, cauliflower, cucumber, potato, leafy vegetables and spices are also grown. Agricultural crops such as wheat, rice, plus, millets and various self-grown grasses are common. Due to the variety of species in home gardens, they provide diverse and multiple services for the households as compared to a monocropping system. However, with a change in altitude, the combination of species changes because of the physical environment, ecological characteristics, socioeconomic and cultural factors [12]. Home gardens play an important role in in situ conservation of genetic resources [13,14].

In home gardens of the Garhwal Himalayan region, different Citrus species are grown, e.g., C. limon (lemon), C. maxima (limon, locally called Chakotara), C. nobilis (orange or narangi), C. pseudoliomon (galgal), and C. reticulata (santara), including C. sinensis, the fruit of the present study. Amongst these, C. sinensis has the most area under cultivation. C. sinensis grows in wide altitudinal ranges from 800 to 2000 m asl in the Western Himalaya. With increasing altitude, the climatic conditions, i.e., rainfall and temperature also varied. The hypothesis of the present study was that climatic and altitude influences the physicochemical properties of C. sinensis. To understand the hypothesis, the present study was carried out with the objective to determine the effect of climate in altitude on physicochemical properties of C. sinensis in Uttarakhand.

2. Materials and Methods

The soils in this area are usually porous and contain a large amount of gravel. The soils are generally shallow, gravely and brown and dark grey in color, and are moderately acidic to neutral in reaction. Due to rapid water percolation in the soil, its profile has reduced nutrients and the moisture retention capacity results in low soil fertility.

The present study was carried out on C. sinensis fruits collected from home gardens (farmer’s field) from the districts of Garhwal Himalayan region of Uttarakhand (Scheme 1), during the months of December–January (Figure 1A–E). Mature and ripe fruits of C. sinensis were collected randomly from 10 healthy trees from home gardens in the selected sites (

Table 1. Geographical location of C. sinensis fruit (collection sites) in the Garhwal Himalaya.

Source Site	Districts	Altitude (m asl)	Latitude N	Longitude E	Mean Annual Rainfall (mm)	Mean Temperature (°C)
Satpuli	Pauri Garhwal	900	29°55′4′′	78°42′38′′	854	32
Kafald	Pauri Garhwal	1000	30°17′34′′	78°40′42′′	869	31
Bhatgaon	Tehri Garhwal	1095	30°10′30′′	78°39′18′′	840	30
Kirada	Tehri Garhwal	1190	30°14′6′′	78°29′33′′	813	32
Pabeth	Tehri Garhwal	1200	30°12′44′′	78°36′24′′	875	34
Bhutli	Tehri Garhwal	1260	30°13′34′′	78°31′12′′	811	29
Amsarigaon	Tehri Garhwal	1310	30°14′23′′	78°28′13′′	915	30
Lawa	Tehri Garhwal	1325	30°14′15′′	78°29′26′′	1020	28
Bamangaon	Tehri Garhwal	1375	30°24′31′′	78°24′38′′	1087	29
Soni	Tehri Garhwal	1415	30°16′53′′	78°46′30′′	1112	29
Ukhimath	Rudraparyag	1460	30°30′54′′	79°4′39′′	1376	24
Guptkashi	Rudraparyag	1550	30°31′35′′	79°4′57′′	1374	26
Nawasu	Rudraparyag	1580	30°13′7′′	78°54′53′′	1205	28
Museti	Pauri Garhwal	1600	30°15′45′′	78°46′54′′	1278	27
Chuncha	Pauri Garhwal	1650	30°8′57′′	78°46′40′′	1293	26
Gumalgaon	Tehri Garhwal	1650	30°18′54′′	78°46′33′′	1374	24
Phata	Rudraparyag	1650	30°34′41′′	79°2′16′′	1324	21
Durgadhar	Rudraparyag	1650	30°20′53′’	79°1′39”	1247	21
Naugaonkhal	Pauri Garhwal	1680	29°57′48′’	78°52′6”	1220	22
Kandai	Pauri Garhwal	1700	30°09′9′’	78°46′36”	1208	20
Paurigaon	Pauri Garhwal	1735	30°09′20′’	78°46′24”	1175	19
Vishalkhal	Chamoli	1750	30°20′34′’	79°11′53”	1220	19
Bhanaj	Rudraparyag	1800	30°25′14′’	79°8′18”	1125	21
Pauri	Pauri Garhwal	1814	30°8′24′’	78°46′45”	1257	18.5
Gwaldam	Chamoli	1829	30°01′0′’	79°34′57”	1347	18
Joshimath	Chamoli	2030	30°33′11′’	79°33′47”	1485	18

). Healthy plants of C. sinensis were selected 100–300 m apart to avoid narrowing down the variation due to relatedness or inbreeding [15].

From all study sites, 1000 mature fruits of C. sinensis were randomly harvested (100 from each tree). The collected fruits were taken in cotton bags, an accession number was allotted (fruit growing sites) and they were brought to the laboratory in the Department of Horticulture, H.N.B. Garhwal University, Srinagar Garhwal for analysis and stored in a cool place. From each place, 100 fruits were selected randomly to measure the fruit length and width, and peel thickness and weight (five replicates with 20 fruit each) from each source, recorded with the help of a digital vernier caliper. The length was taken from the apex to the stem end. For each site, 700 fruits (seven replicates each of a hundred fruits) were randomly selected for measuring the fruit weight using the electronic top loading balance for getting an accurate reading as per ISTA [16]. The number of juice sacks, healthy and rudimentary seed and total seed per fruit (five replicated 20 each) were counted manually and the average was calculated from each source.

Fruit juice was extracted and various methods were applied for estimation of soluble sugars by McCready et al. [17]; the acidity of fruits was estimated by titrating the fruit juice [18]; ascorbic acid was estimated by using 2,6-Dichlorophenol indophenol (DCPIP) visual titration method [19], and the total soluble solids were determined by using a refractometer. The data were analyzed according to the procedure of analysis of randomized block design. The significant variation among the population was observed by applying analysis of variance (ANOVA), the critical difference (C.D.) test at the 5% probability level and the Pearson correlation coefficient was estimated by using the statistical software package and WASP 1 -Web Agri Stat Package IGAR Goa, and p-value for Pearson correlation was corrected with Bonferroni correction. JMP statistical software pro 14.0.0 was used for multivariate analysis of variance.

3. Results

The minimum fruit length and fruit breadth (5.63 and 5.83 cm) were recorded in the Satpuli population and the maximum (8.16 cm and 8.36 cm) fruit length and breadth in the Bhatgaon population. The average fruit length and breadth was reported as 6.66 and 6.83 cm, respectively, irrespective of population. Regarding fruit weight, the minimum (96.64 g/fruit) was observed in Satpuli and the maximum (296.86 g/fruit) in the Bhatgaon population, with a mean fruit weight of 164.62 g/fruit, irrespective of population. The minimum peel thickness (0.4 cm) was recorded in the Ukhimath population and the maximum (0.76 cm) in the Bhatgaon population, while the lowest peel weight (33.54 g/fruit) was observed in the Satpuli population and the highest (94.75 g/fruit) in the Bhatgaon population. On average, the peel thickness and peel weight reported were 0.55 and 53.63 g/fruit, respectively. The minimum juice sacks per fruit recorded (8.66) was in the Gumalgaon and Kafald populations, whereas the maximum (11.66) was in the Durgadhar population, with average juice sacks per fruit being 52.15. The average weight of juice was 62.07 g/fruit. The lowest number of seeds per fruit (11.47) was observed in the Durgadhar population, while the highest (24.24) was in the Satpuli population with an average seeds/fruit of 18.82. However, in the Gwaldam population, rudimentary seeds/fruit were not observed, but the maximum (17.47) rudimentary seeds were recorded in Kirada. The average rudimentary seeds/fruit recorded was 7.42. The minimum seed weight per fruit recorded (1.28 g/fruit) was in the Guptkashi population and the maximum (4.52 g/fruit) in the Pauri population (

Table 2. Effect of altitude on fruit morphology (mean ± SD) of C. sinensis in Garhwal Himalaya.

Source	Altitude (m asl)	Fruit Length (cm)	Fruit Width (cm)	Fruit Weight (g)	Peel Thickness (cm)	Peel Weight (g)	Juice Sacks/Fruit	Juice Weight (g)	Number of Seeds/Fruits	Rudimentary Seeds/Fruit	Seed Weight (g)
Satpuli	900	5.63 ± 1.03	5.83 ± 0.54	96.64 ± 32.11	0.60 ± 0.13	33.54 ± 17.24	10.33 ± 2.54	33.15 ± 17.89	24.24 ± 6.54	16.66 ± 6.74	1.54 ± 0.91
Kafald	1000	7.26 ± 1.31	6.90 ± 1.72	180.59 ± 54.49	0.56 ± 0.12	53.94 ± 21.22	8.66 ± 1.72	68.91 ± 21.36	16.66 ± 7.21	7.33 ± 3.45	3.20 ± 1.02
Bhatgaon	1095	8.16 ± 1.10	8.36 ± 1.52	296.86 ± 107.29	0.76 ± 0.21	94.75 ± 24.76	11.24 ± 1.99	111.32 ± 31.11	22.66 ± 13.37	12.52 ± 5.87	3.07 ± 1.01
Kirada	1190	6.16 ± 0.91	6.53 ± 2.31	129.96 ± 52.98	0.60 ± 0.11	45.85 ± 16.69	10.33 ± 2.34	45.61 ± 23.31	19.33 ± 14.42	17.47 ± 6.41	2.09 ± 0.86
Pabeth	1200	6.43 ± 2.88	6.76 ± 1.73	147.92 ± 59.99	0.56 ± 0.17	49.7 ± 23.12	11.00 ± 3.01	36.38 ± 22.58	15.24 ± 8.99	14.33 ± 5.11	2.38 ± 0.56
Bhutli	1260	6.66 ± 1.12	6.73 ± 1.73	137.77 ± 43.28	0.53 ± 0.21	44.09 ± 24.32	10.66 ± 3.54	57.90 ± 32.18	20.12 ± 11.52	16.66 ± 8.25	3.27 ± 0.76
Amsarigaon	1310	6.83 ± 1.41	7.36 ± 2.65	151.35 ± 68.39	0.56 ± 0.24	52.33 ± 17.89	11.00 ± 4.47	74.84 ± 37.89	18.66 ± 13.23	6.89 ± 3.21	3.54 ± 0.97
Lawa	1325	6.03 ± 1.86	7.46 ± 2.34	221.78 ± 102.27	0.73 ± 0.19	70.83 ± 24.57	10.33 ± 3.93	101.98 ± 35.27	16.57 ± 10.4	7.66 ± 4.86	1.60 ± 0.37
Bamangaon	1375	6.90 ± 1.32	7.93 ± 1.79	227.79 ± 91.28	0.56 ± 0.21	57.19 ± 23.69	10.66 ± 5.34	95.11 ± 28.59	18.66 ± 9.45	4.66 ± 2.11	1.87 ± 0.61
Soni	1415	6.66 ± 2.01	6.30 ± 1.72	141.87 ± 87.90	0.43 ± 0.33	38.82 ± 21.11	9.08 ± 5.38	53.00 ± 31.98	15.54 ± 11.74	7.33 ± 3.17	3.22 ± 1.01
Ukhimath	1460	7.23 ± 1.92	7.10 ± 2.02	172.05 ± 67.31	0.40 ± 0.21	64.81 ± 23.21	10.33 ± 5.93	46.15 ± 23.58	10.33 ± 11.95	3.24 ± 1.11	3.55 ± 0.92
Guptkashi	1550	5.86 ± 2.46	6.06 ± 1.55	137.77 ± 89.12	0.66 ± 0.30	37.05 ± 17.11	10.04 ± 4.98	46.32 ± 27.81	15.08 ± 10.54	6.33 ± 2.93	1.28 ± 0.12
Nawasu	1580	5.86 ± 2.31	6.00 ± 1.69	103.54 ± 32.13	0.46 ± 0.27	35.40 ± 15.58	10.66 ± 3.33	34.27 ± 15.44	16.00 ± 12.21	9.00 ± 2.95	1.79 ± 0.27
Museti	1600	6.86 ± 1.83	7.26 ± 2.29	182.68 ± 47.51	0.56 ± 0.19	69.44 ± 24.12	9.33 ± 4.52	52.38 ± 21.63	14.66 ± 9.67	9.66 ± 3.01	3.15 ± 1.10
Chuncha	1650	6.12 ± 2.21	5.90 ± 1.01	114.11 ± 52.18	0.56 ± 0.17	67.01 ± 26.71	9.66 ± 4.90	75.24 ± 26.83	17.33 ± 11.69	5.00 ± 1.01	3.25 ± 0.98
Gumalgaon	1650	6.93 ± 1.01	6.96 ± 0.99	187.18 ± 66.78	0.46 ± 0.18	48.52 ± 24.32	8.66 ± 3.92	69.58 ± 24.68	23.33 ± 5.35	9.00 ± 3.11	3.18 ± 0.91
Phata	1650	7.08 ± 1.98	6.86 ± 1.92	158.95 ± 71.21	0.63 ± 0.19	37.51 ± 25.43	9.33 ± 4.01	57.69 ± 31.11	18.07 ± 7.62	4.00 ± 0.98	1.78 ± 0.66
Durgadhar	1650	7.30 ± 1.97	7.66 ± 2.69	217.33 ± 101.24	0.50 ± 0.09	77.34 ± 26.72	11.66 ± 4.58	64.94 ± 36.72	11.12 ± 8.95	4.00 ± 1.11	4.04 ± 1.27
Naugaonkhal	1680	7.60 ± 1.31	7.43 ± 2.37	147.67 ± 53.47	0.46 ± 0.11	71.41 ± 27.99	10.33 ± 4.67	53.84 ± 27.21	15.66 ± 9.68	2.23 ± 0.82	4.10 ± 1.32
Kandai	1700	6.56 ± 2.11	6.83 ± 1.97	164.11 ± 66.90	0.50 ± 0.18	40.35 ± 12.32	10.33 ± 5.89	76.45 ± 31.22	19.33 ± 8.68	4.66 ± 0.79	3.58 ± 1.22
Paurigaon	1735	6.76 ± 1.47	6.56 ± 1.32	154.25 ± 59.09	0.43 ± 0.22	57.55 ± 16.45	10.66 ± 5.51	67.43 ± 28.92	19.33 ± 11.79	5.33 ± 2.23	3.26 ± 0.89
Vishalkhal	1750	6.66 ± 1.89	7.10 ± 2.91	173.61 ± 65.09	0.50 ± 0.15	34.94 ± 13.89	10.33 ± 4.92	74.69 ± 34.22	24.24 ± 13.45	9.27 ± 3.47	3.66 ± 1.09
Bhanaj	1800	5.86 ± 0.92	5.86 ± 2.34	183.32 ± 89.54	0.66 ± 0.32	66.38 ± 21.62	10.53 ± 4.89	63.68 ± 32.13	16.33 ± 14.83	1.28 ± 0.36	1.59 ± 0.43
Pauri	1814	6.26 ± 2.02	6.93 ± 2.21	158.02 ± 54.32	0.46 ± 0.18	53.06 ± 17.81	11.08 ± 5.58	66.81 ± 33.14	24.14 ± 11.87	3.14 ± 0.34	4.52 ± 1.42
Gwaldam	1829	6.93 ± 1.92	6.06 ± 1.92	144.14 ± 69.97	0.56 ± 0.21	42.46 ± 21.84	10.33 ± 5.43	39.70 ± 18.91	12.33 ± 9.76	0.00 ± 0.00	1.29 ± 0.64
Joshimath	2030	6.52 ± 1.92	6.93 ± 2.01	148.97 ± 99.90	0.56 ± 0.22	50.05 ± 19.48	10.66 ± 6.34	46.54 ± 19.32	18.33 ± 11.32	5.26 ± 1.17	3.54 ± 0.78
Mean		6.66	6.83	164.62	0.55	53.63	52.15	62.07	17.82	7.42	2.82
CD 5 %		0.73	0.63	126.6	1.62	24.19	1.17	34.49	10.16	9.66	1.01

). The average seed weight/fruit was 2.82 g, irrespective of population.

On average, irrespective of population, total soluble solids reported were 10.10%, citric acid was 4.13%, ascorbic acid 54.77 mg/100 mL, and soluble sugar contents were 6.34 %. The lowest total soluble solids recorded (7.73 %) were in the Kirada population and the highest (12.76%) in the Ukhimath population. The minimum citric acid (3.20%) was observed in the Soni population while the maximum (6.68%) was in the Gwaldam population. Amongst the populations, the lowest ascorbic acid contents (31.45 mg/100 mL) were recorded in Bhatgaon and the highest (86.45 mg/100 mL) in the Ukhimath population. Similarly, the minimum soluble sugar contents (4.65%) were recorded in Ukhimathand the maximum (9.27%) in the Bhatgaon population (

Table 3. Effect of altitude on nutrients content (mean ±SD) of C. sinensis in Garhwal Himalaya.

Source	Altitude (m asl)	Total Soluble Solids (%)	Citric Acid (%)	Ascorbic Acid (mg100 g−1)	Soluble Sugar (%)
Satpuli	900	8.00 ± 1.17	4.86 ± 1.27	74.41 ± 5.69	5.96 ± 0.32
Kafald	1000	9.53 ± 2.01	3.71 ± 1.28	60.90 ± 6.87	5.99 ± 0.50
Bhatgaon	1095	10.13 ± 2.22	3.52 ± 1.93	31.45 ± 6.32	9.27 ± 0.38
Kirada	1190	7.73 ± 1.96	4.03 ± 1.79	34.89 ± 3,45	5.25 ± 0.45
Pabeth	1200	9.80 ± 1.45	4.28 ± 2.11	40.56 ± 5.32	6.64 ± 0.61
Bhutli	1260	10.73 ± 2.63	4.04 ± 1.69	52.80 ± 6.19	8.86 ± 0.47
Amsarigaon	1310	9.40 ± 2.01	3.54 ± 0.92	39.93 ± 2.39	8.42 ± 0.68
Lawa	1325	10.46 ± 2.88	4.89 ± 2.32	37.72 ± 3.91	7.56 ± 0.33
Bamangaon	1375	11.23 ± 3.11	4.50 ± 2.11	39.94 ± 5.09	5.48 ± 0.47
Soni	1415	8.53 ± 1.97	3.20 ± 1.79	34.57 ± 4.19	5.59 ± 0.31
Ukhimath	1460	12.76 ± 3.47	3.28 ± 0.94	86.45 ± 7.18	4.65 ± 0.32
Guptkashi	1550	10.96 ± 2.97	3.93 ± 1.09	53.15 ± 5.61	5.35 ± 0.23
Nawasu	1580	9.80 ± 2.13	5.01 ± 2.03	44.66 ± 4.59	5.16 ± 0.29
Museti	1600	8.50 ± 2.31	3.26 ± 1.81	54.23 ± 5.32	5.96 ± 0.41
Chuncha	1650	9.66 ± 3.33	3.94 ± 1.39	58.94 ± 5.62	5.29 ± 0.27
Gumalgaon	1650	8.40 ± 2.97	3.84 ± 1.37	42.11 ± 3.39	5.14 ± 0.26
Phata	1650	12.46 ± 3.48	3.62 ± 1.58	45.67 ± 5.60	5.24 ± 0.36
Durgadhar	1650	11.66 ± 3.46	3.68 ± 0.79	79.33 ± 6.01	5.96 ± 0.42
Naugaonkhal	1680	11.03 ± 4.11	3.04 ± 1.24	75.33 ± 6.73	5.96 ± 0.39
Kandai	1700	9.73 ± 2.79	3.68 ± 1.31	78.56 ± 4.93	5.49 ± 0.41
Paurigaon	1735	11.20 ± 3.28	3.20 ± 1.38	68.67 ± 4.79	6.65 ± 0.37
Vishalkhal	1750	11.80 ± 2.90	4.40 ± 1.88	60.06 ± 4.32	5.24 ± 0.33
Bhanaj	1800	8.70 ± 1.75	5.46 ± 1.73	40.88 ± 3.33	7.03 ± 0.57
Pauri	1814	8.53 ± 1.39	3.79 ± 1.11	83.40 ± 3.84	5.82 ± 0.32
Gwaldam	1829	11.93 ± 3.41	6.68 ± 2.37	46.47 ± 2.22	8.51 ± 0.23
Joshimath	2030	10.00 ± 2.56	5.96 ± 2.19	58.89 ± 2.87	8.28 ± 0.29
Mean		10.10	4.13	54.77	6.34
CD 5 %		1.66	1.13	3.51	0.49

).

There was significant (p < 0.01) effect of fruit weight on fruit length, fruit width, peel thickness, juice weight and seed weight. Whereas; significant (p < 0.005) effects on the total soluble solid and citric acid (

Table 4. MANOVA for fruit weight vs fruit morphology and nutritive properties of C. sinensis.

Source of Variation	DF	F Ratio
		Fruit Length	Fruit Width	Peel Thickness	Peel Weight	Juice Sacks/Fruit	Juice Weight	Number of Seeds/Fruits	Rudimentary Seeds/Fruit	Seed Weight	Total Soluble Solids	Citric Acid	Ascorbic Acid	Soluble Sugar
Fruit Weight	1	17.94 **	25.74 **	18.15 **	1.02 ns	1.09 ns	23.22 **	2.43 ns	0.61 ns	6.27 **	4.61 *	4.69 *	1.61 ns	1.80 ns

** Significant at p < 0.01; * Significant at p < 0.05; NS- non significant.

).

Altitude was significantly related to fruit length and inversely correlated with rudimentary seeds/fruit of C. sinensis. Latitude showed a significant positive correlation with fruit weight, fruit length and fruit width. The number of seeds/fruit and rudimentary seeds/fruit was revealed to be positively and significantly (p < 0.01) correlated with longitude. Rainfall was significantly negatively correlated with rudimentary seeds. Temperature had a significant positive correlation with fruit length, fruit width and rudimentary seeds (

Table 5. Correlation coefficient between geographical variable with morphological and nutrient contents of C. sinensis.

Geographical Variable	FWt	FL	FW	PT	P Wt	J S	J Wt	NS	RS	S Wt	TSS	CA	AA	SS
Altitude	−0.16	0.51 **	0.00	−0.34	0.30	0.11	−0.11	−0.14	−0.70 **	0.24	0.27	0.05	0.26	−0.14
Latitude	0.43	0.51 **	0.51 **	0.20	0.30	0.13	0.27	−0.21	−0.02	0.11	0.24	0.01	−0.27	0.26
Longitude	0.01	−0.18	0.00	−0.02	−0.20	0.11	0.17	0.49 **	0.45 **	0.06	−0.46 **	0.14	−0.29	0.13
Rainfall	0.01	−0.13	−0.10	−0.35	−0.08	−0.27	−0.19	−0.29	−0.70 **	0.14	0.36	0.13	0.35	−0.34
Temperature	−0.11	0.73 **	0.81 **	0.39	0.27	−0.05	−0.26	0.32	0.72 **	−0.14	−0.41	−0.19	−0.47 **	0.04

Abbreviation: F Wt = fruit weight, FL = fruit length, FW = fruit width, Pt = peel thickness, Wt = peel weight, JS = juice sacks, J Wt = juice weight, NS = number of seeds, RS = rudimentary seeds, S Wt = seed weight, TSS = total soluble solids, CA = citric acid, AA = ascorbic acid, SS = soluble sugar. ** significant at p < 0.01.

). Physicochemical characteristics exhibited significant variations among the populations (

Table 6. Analysis of variation for various morphological and nutrient contents among and within the fruit source of C. sinensis.

Source of Variation	D F	F-Value
		FL	FW	F Wt	S Wt	NS	RS	P Wt	P T	JS	J Wt	TSS	C A	AA	SS
Treatment	25	5.49 **	8.78 **	2.84 *	7.28 **	14.52 **	2.00 ns	3.36 *	3.28 *	3.06 *	2.98 ns	13.84 **	6.03 **	183.28 **	143.18 **
Replicate	4	2.07	3.19 *	1.87	1.86	3.13 *	0.63	0.66	2.32 *	0.29	2.30	0.11	1.11	0.44	1.22

Abbreviation: F Wt = fruit weight, FL = fruit length, FW = fruit width, Pt = peel thickness, Wt = peel weight, JS = juice sacks, J Wt = juice weight, NS = number of seeds, RS = rudimentary seeds, S Wt = seed weight, TSS = total soluble solids, CA = citric acid, AA = ascorbic acid, SS = soluble sugar. * Significant at p < 0.05, ** significant at p < 0.01.

).

4. Discussion

The results of the present investigation reveal significant differences among the populations for physicochemical properties of C. sinensis fruits. In general, the composition of nutrients, i.e., sugar, acids, vitamins, minerals, and other parameters such as aroma, fiber, texture, and flavor are essential components for the determination of fruit quality. Plant genotypes, growing conditions, maturity and time of harvesting significantly influenced the parameters of these fruits [20,21]. C. sinensis fruits were collected from a wide range of altitudinal sites for the estimation of physicochemical characters. Thus, physicochemical properties of C. sinensis fruits were influenced by the geography (altitude, latitude, longitude, rainfall and temperature) of the growing area. The variation in geography directly corresponded with the climactic factors of the area such as temperature, rainfall, humidity, sunshine, phasing of sites/slopes, air currents, nutritional status of soil, moisture condition of soil, and pH of soil of the area, always with a chance of variations in these quality parameters of fruits being influenced or produced by a new genotype. The climatic factor also inhibits the normal crop load and vigor of the plants, which directly influences the morphological and nutrients contents of the fruits [22]. Variation in different physicochemical characters were also reported in Pyrus germplasms [23], Rubus idoeus, R. discolor [24], Psidium guajava [21], Mangifera indica [25], Citrus macroptera [26], Choerospondies axillaries [27], Citrus sinensis [28], Citrus aurantiifolia, C. limon and C. pseudolimon [29], Mangifera indica [30], Phyllanthus emblica [31] Ziziphus jujube [32], Vaccinium myrtillus [33].

The correlation coefficient matrix between fruit morphology of C. sinensis shows that fruit weight had a significant positive correlation with fruit width, peel thickness, peel thickness weight, and juice weight. These results are in agreement with the study in which a significant correlation coefficient was reported between fruit weight with other morphological traits of fruits in Ziziphus nummularia, Ziziphus spina-christi and Ziziphus oxyphylla [34], Prunus cerasus [35] and Elaeagnus angustifolia [36]. Significant correlations between morphometric characters which influenced the yield and quality of fruits should be important for a breeding program of any valuable fruit species [35]. It is necessary to undertake an evaluation of valuable species [36].

Physical parameters in pomegranate fruits had significant variation among the locations of collection sites [37]. Ali et al. [38] determined the effects of altitude on walnut fruit quality and found that fruit quality is influenced by altitude. The results of the present study reveal that altitude significantly influenced fruit length and peel thickness and rudimentary seeds significantly decrease as altitude increases. Out of fourteen physicochemical parameters in C. sinensis, nine parameters were significantly correlated with geographical variables (altitude, latitude, longitude, rainfall and temperature). Among these geographical variables, temperature and rainfall were the important factors which greatly influenced the physicochemical properties of C. sinensis. Physicochemical parameters showed a positive significant correlation with fruit length and an inverse significant relationship between peel thickness and rudimentary seeds depending on altitude. Latitude was positively significantly correlated with fruit weight, fruit length and fruit breadth, indicating a northern trend. The longitude exhibited a positive correlation between the number of seeds/fruit and rudimentary seeds/fruit, indicating that this trait increases towards eastern extremes. The inverse correlation of longitude with total soluble solids indicates that these traits increase towards the western extremes. Rainfall significantly decreased the peel thickness, rudimentary seeds and soluble sugar while increasing the total soluble solids and ascorbic acid. Temperature significantly increased the fruit length, fruit width, peel thickness, number of seeds and rudimentary seeds while decreasing the total soluble solids and ascorbic acid. Morphological and chemical variation in Phyllanthus emblica fruit were also studied [39] and Phyllanthus emblica fruits from different growing sites are reported to have morphological and chemical variation.

Ahmed et al. [23] suggest that variability accounting for fruit quality is due to either genotypes or environmental conditions prevailing in the growing areas or interaction of both factors. Shiraishi et al. [40] also report that changes in the locality (site), topography, and environment influence the pheno-physiological parameters such as bud burst, berry growth and development, berry size, numbers of berries per bunch, time of maturity and ripening and biochemistry; soluble sugar contents, titrable acidity, sugars, amino acids, organic acids, phenolic compounds, and total antioxidants varied significantly in table grape varieties. The variability in fruit quality of C. sinensis may be due to similar interactions. These results were also in line with the findings of Candiret et al. [41] on persimmon fruits. Thakur et al. [37] assume that the variations in total soluble solids of pomegranate fruits in different locations may be due to localized conditions. Almanza et al. [42] carried out work on this characteristic of ‘Pinot Noir’ grapevine fruit. Among the physicochemical characteristics of fruits, no specific trend was observed at any particular location. That means no single parameter was found to be dominant in multiple locations. It was assumed that the variations in various physicochemical characteristics of fruits in different locations may be due to localized conditions.

5. Conclusions

The morphometric parameters and nutrient contents of C. sinensis were significantly varied among the different populations in the Garhwal Himalaya. These estimated variations in morphometric character of C. sinensis also could be useful for a future breeding program for improving this valuable fruit species in the hill region of Uttarakhand, India. The high nutrient contents in this potential species, particularly the rich source of vitamin C, need to be conserved to enhance the immunity of the human body in present scenarios such as COVID-19. The low temperature and high rainfall areas were found suitable for the cultivation of C. sinensis quality fruits. Further studies related to genetic variability, selflife, storage life, and processing technology should be conducted to estimate the variation, long-term storage and value addition in C. sinensis in the Garhwal Himalaya region. The fruit’s mature time is the winter season in hilly areas; this does not provide proper market value for the grower cultivating; thus, proper storage and transport facilities should be enhanced to maximize the benefit for marginal farmers to cultivate the C. sinensis in home gardens, agroforestry systems and sloped lands.