Studies on the impact of pre-soaking seed treatments on germination and seedling growth parameters of Jackfruit (Artocarpus heterophyllus Lam.)

Introduction

Jackfruit (Artocarpus heterophyllus Lam.) is a member of the Moraceae family with 2n = 56 chromosomes and also known for producing the largest fruit among all fruit bearing plants. The botanical genus name Artocarpus is derived from the Greek words artos meaning "bread" and carpos meaning "fruit," reflecting the bread like texture of its edible species (Bailey, 1949) [4] . The commercial jackfruit cultivars belong to a single species, A. heterophyllus. Additionally, significant species of the genus Artocarpus include A. lakoocha (monkey jack), A. altilis or A. communis (breadfruit), A. hirsutus (wild jack), A. camansi (breadnut), A. odoratissima (marang) and A. lingnanesis (kwaimuk) (Saxena et al., 2011) [20] . It is originated from the evergreen rain forests of the Western Ghats in India, where it naturally grows in warm and humid conditions (Haq, 2006) [12] . It requires moist, well-drained soil with a pH between 4.3 to 8.0 and medium soil fertility. The ideal temperature is between 19 to 29℃, the altitude is about 1600 meters above sea level and the yearly rainfall ranges from 1000 to 2400 mm (Prakash et al., 2009) [16] . It is a multiple fruit (sorosis) and the edible portion is the fleshy perianth (aril/bulbs). It is a climacteric fruit and continuing to ripen after harvest. The optimum stage of harvest maturity in raw jackfruit has been observed to be 90-100 days after the appearance of the spike. The dense, waxy seeds are oval, oblong, or ellipsoid in shape, weigh 2.5-14 g, measure 2-4 × 1-2 cm and have a coriaceous testa, with each syncarp typically containing 100-500 seeds (Gunasena et al., 1996) [11] . The major producers of jackfruit are India, Vietnam, Malaysia, Myanmar, Indonesia, Bangladesh, Sri Lanka, Brazil, the West Indies, Pakistan and other tropical countries. India, often referred to as the "Motherland of Jackfruit," is one of the world's leading producers (Sidhu, 2012) [21] . It is frequently described as the "poor man's food" in eastern and southern India. In India, it is extensively found in Kerala, Assam, Odisha, Bihar, Tamil Nadu, Madhya Pradesh, Chhattisgarh and the northern Indian foothills of the Himalayas (Anon., 2024a) [2] . In Chhattisgarh, the major jackfruit producing districts are Raigarh, Mahasamund, Bilaspur, Kanker, Kondagaon and Jashpur (Anon., 2024b) [3] . The ripe fruit is a good source of calories, vitamins and minerals, it makes a major nutritional contribution to low income households. The fruits can be consumed raw or processed into pickles and other products. It has two distinct textures when ripe: Khaja, which has a solid perianth and Ghila, which has a watery, pulpy perianth (Rahman et al., 1999) [17] . It is an important calorie source for human nutrition with ripe fruit containing 98 kcal, 1.3-1.9 g protein, 0.1-0.3 g total fat, 18.9-25.4 g carbohydrates and 1-1.1 g dietary fiber per 100 g of edible portion (Vinning and Moody, 1997) [23] . The majority of nations that grow jackfruit use seed propagation. Its seeds are naturally recalcitrant. Recalcitrant seeds have a tendency to lose their viability when desiccated and have a comparatively high moisture content. Because of their vulnerability to desiccation and chilling, the resistant seeds provide significant storage challenges. Pre-sowing treatments have been shown to improve germination and seedling growth by synchronizing and promoting quick seedling emergence. Seed treatments are essential in jackfruit to increase seed germination and seedling growth (Chin and Roberts, 1980) [6] . Chemicals such as KNO 3 and thiourea are used to break the dormancy of seeds or to enhance germination. Potassium nitrate (KNO 3 ) promotes seed germination in fruit crops by breaking physiological dormancy and enhancing enzyme activity. Thiourea is a nitrogen and sulphur containing compound. In the context of seed germination, thiourea enhances key physiological and biochemical processes such as nitrogen and proline metabolism, enzyme activity, defense responses and water relations. It has been noted that chemical treatment has a major role in breaking dormancy, germination of seeds and plant growth and development (Mithlesh et al., 2025) [14] . Organic seed treatments, specifically vermiwash and cow urine, play vital roles in enhancing seed germination and seedling development. Vermiwash obtained from earthworm beds contains a variety of growth regulating substances (Nielson, 1965) [15] . Cow urine is rich in physiologically active compounds like growth regulators, iron, urea, uric acid, estrogen's and progesterone. Therefore, it improves seedling growth by enhancing aeration, porosity and water uptake which results in improved seed germination, shoot length and overall enhancement of seedling vigour (Joshi and Adhikari, 2019; Choudhary et al., 2023) [13,7] . This investigation aims to determine most suitable pre-soaking seed treatments to enhance seed germination and ensure standardized practices for jackfruit seedling production.

Materials and Methods

The present investigation was conducted at the Horticulture Nursery, Department of Fruit Science, College of Agriculture, Indira Gandhi Krishi Vishwavidyalaya, Raipur, Chhattisgarh located at a height of 298.15 meters above mean sea level and located at a latitude of 21.25°N and 81.62°E longitude during the year 2025-2026. The investigation was designed using a completely randomized design (CRD) with three replications and including 13 different treatments viz.T0: control, T 1: KNO 3 @ 0.5% for 3 hrs., T 2: KNO 3 @ 1.0% for 3 hrs., T 3: KNO 3 @ 1.5% for 3 hrs., T 4: thiourea @ 0.5% for 1 hr., T 5: thiourea @ 1.0% for 1 hr.,T 6: thiourea @ 1.5% for 1 hr., T 7: cow urine @ 2% for 12 hrs., T 8: cow urine @ 3% for 12 hrs., T 9: cow urine @ 5% for 12 hrs., T 10: vermiwash @ 2% for 12 hrs., T 11: vermiwash @ 3% for 12 hrs. and T 12: vermiwash @ 5% for 12 hrs. as represented in table 1. Fresh jackfruit seeds were sown after soaking for different durations of soaking hours of their respective treatments in 8"×6" poly bags with a thickness of 200 gauge filled with growing medium composed with soil, FYM and sand mixture (2:1:1) and irrigated at 1-2 days interval to maintain moisture content.

Results and Discussion

The data pertaining to germination percentage of the jackfruit seed was presented in Table 2. The maximum germination percentage (80.92%) for jackfruit seeds was observed under the treatment T3 (KNO 3 @1.5%) statistically at par with the treatment T 2 (KNO 3 @1.0%) having value of 77.56%. The treatment T 2 was statistically at par with the treatment T 6 (Thiourea @1.5%) showed 74.97%. However, the minimum germination percentage (52.46%) recorded under the treatment T 0 (control). This advancement in germination percentage could be attributed to KNO 3 role in activates hydrolytic enzymes like α-amylase for effective mobilization of stored food reserves and promotes respiration and embryo growth. Radicle emergence was facilitated by these physiological reactions, leading to higher and more uniform germination. Similar findings were also shown by Gurung et al. (2014) [10] in passion fruit, Bhavya et al. (2017) [5] in karonda, Rai et al. (2018) [18] in Khirni and Giri et al. (2023) [9] in papaya, where suitable pre-sowing seed treatments greatly enhanced germination.

The data on height of seedling (cm) as influenced by different pre-soaking seed treatments, recorded at 15, 30, 45, 60, 75 and 90 DAS (days after sowing), are presented in Table 2. At 15 DAS, the maximum height of seedling (5.55 cm) was recorded under the treatment T3 (KNO 3 @1.5%), followed by the treatment T 2 (KNO 3 @1.0%) having value of 5.11 cm while the minimum (0 cm) was observed under the treatment T 0 (control). At 30 DAS, the maximum height of seedling (16.59 cm) was recorded under the treatment T 3 , followed by the treatment T 2 having value of 15.11 cm while the minimum (10.31 cm) was observed under the treatment T 0 . At 45 DAS, the maximum height of seedling (24.39 cm) was recorded under the treatment T 3 , statistically at par with the treatment T 2 having value of 23.66 cm while the minimum (15.96 cm) was observed under the treatment T 0 . At 60 DAS, the maximum height of seedling (32.19 cm) was recorded under the treatment T 3 statistically at par with the treatment T 2 having value of 31.21 cm while the minimum (21.61 cm) was observed under the treatment T 0 . At 75 DAS, the maximum height of seedling (38.98 cm) was recorded under the treatment T 3 statistically at par with the treatment T 2 having value of 37.77 cm while the minimum (27.27 cm) was observed under the treatment T 0 . At 90 DAS, the maximum height of seedling (46.78 cm) was recorded under the treatment T 3 statistically at par with the treatment T 2 having value of 45.32 cm while the minimum (33.92 cm) was observed under the treatment T 0 .

The current results align with those of Rajamanickam et al. (2002) [19] in aonla, Aatla and Srihari (2013) [1] in mango, Bhavya et al. (2017) [5] in karonda and Mithlesh et al. (2025) [14] in jackfruit, all of which found that KNO 3 seed treatment greatly increased seedling height and vigor as compared to the control.

The data pertaining to diameter of seedling (mm) as impact of various pre-soaking seed treatments on jackfruit, observed at 15, 30, 45, 60, 75 and 90 DAS, are demonstrated in Table 2. At 15 DAS, the maximum diameter of seedling (1.09 mm) was recorded under the treatment T3 (KNO 3 @1.5%), followed by the treatment T 2 (KNO 3 @1.0%) having value of 1.01 mm while the minimum (0 mm) was observed under the treatment T 0 (control). At 30 DAS, the maximum diameter of seedling (3.02 mm) was recorded under T 3 , followed by T 2 having value of 2.91 mm and T 0 observed the minimum value (1.61 mm). At 45 DAS, the maximum diameter of seedling (3.53 mm) was recorded under T 3 , followed by T 2 having value of 3.41 mm while the minimum (1.86 mm) was observed under T 0 . At 60 DAS, the maximum diameter of seedling (4.27 mm) was recorded under T 3 , followed by T 2 having value of 4.02 mm and the minimum (2.26 mm) was observed under T 0 . At 75 DAS, the maximum diameter of seedling (4.91 mm) was recorded under T 3 , followed by T 2 having value of 4.67 mm while the minimum (2.53 mm) was observed under T 0 . At 90 DAS, the maximum diameter of seedling (5.83 mm) was recorded under T 3 , followed by T 2 having value of 5.56 mm and the minimum (2.95 mm) was observed under T 0 . The recorded increase in diameter of seedling may be attributed to the role of KNO3 at various vegetative growth stages, as potassium improves enzyme performance, photosynthesis, glucose translocation and water regulation, whereas nitrate acts as both a food and a signaling molecule, stimulating cell division and protein synthesis (Duermeyer et.al.,2018) [8] . Similar results were reported by Aatla and Srihari (2013) [1] in mango and Bhavya et al. (2017) [5] in karonda, who noted increased seedling vigor and stem diameter after seed treatment with KNO 3 .

Number of leaves/seedling

The results pertaining to number of leaves/seedling as influenced by various pre-soaking seed treatments on jackfruit, recorded at 15, 30, 45, 60, 75 and 90 DAS, are demonstrated in Table 2. At 15 DAS, the maximum number of leaves/seedling (1.21) was recorded under the treatment T3 (KNO 3 @1.5%), followed by the treatment T 2 (KNO 3 @1.0%) having value of 1.07 while the minimum (0) was observed under the treatment T 0 (control). At 30 DAS, the maximum number of leaves/seedling (3.34) was recorded under T 3 , followed by T 2 having value of 2.83 and the minimum (1.65) was observed under T 0 . At 45 DAS, the maximum number of leaves/seedling (4.71) was recorded under T 3 , followed by T 2 having value of 4.25 while the minimum (2.47) was observed under T 0 . At 60 DAS, the maximum number of leaves/seedling (6.28) was recorded under T 3 , followed by T 2 having value of 5.67 and the minimum (3.29) was observed under T 0 . At 75 DAS, the maximum number of leaves/seedling (7.85) was recorded under T 3 , followed by T 2 having value of 7.09 while the minimum (4.12) was observed under T 0 . At 90 DAS, the maximum number of leaves/seedling (9.42) was recorded under T 3 , followed by T 2 having value of 8.50 while the minimum (4.94) was observed under T 0 .

More leaves per seedling are produced as a result of faster leaf initiation and development based through enhanced nutrient mobilization and higher cell division in the shoot apical meristem (Taiz et al., 2015) [22] . Similar results were reported by Aatla and Srihari (2013) [1] in mango and Bhavya et al. (2017) [5] in karonda, who noted increased seedling vigor and number of leaves/seedling when seeds were treated with KNO 3 .

Fresh weight of shoot (g) was recorded at 90 DAS as influenced by various pre-soaking seed treatments and data presented in Table 3. Among the different seed treatments, Maximum fresh weight of shoot (13.86 g) was recorded under the treatment T3 (KNO 3 @1.5%), followed by the treatment T 2 (KNO 3 @1.0%) having value of 13.01 g while the minimum (7.41) was observed under the treatment T 0 . This results to faster cell division, larger leaf area and increased biomass accumulation. Vigorous shoot growth is promoted by improved seed reserve mobilization and effective photosynthate translocation, which raises shoot fresh weight. Similar findings were reported by Aatla and Srihari (2013) [1] in mango and Bhavya et al. (2017) [5] in karonda, who noted considerably increased shoot growth and seedling vigor after seed treatment with KNO 3 .

Various seed treatments had significant impacts on the dry weight of shoot (g) of jackfruit seedlings, according to the present investigation's observations, which were recorded at 90 DAS and the results are represented in Table 3. The maximum dry weight of shoot was measured under the treatment T3 (KNO 3 @1.5%) was 4.52 g, followed by the treatment T 2 (KNO 3 @1.0%) having value of 4.33 g. The minimum dry weight (1.34 g) was recorded under the treatment T 0 . Enhanced photosynthesis, nitrogen absorption and effective translocation of carbohydrates stimulated by potassium and nitrate may be responsible for the significantly higher shoot dry weight. Similar findings were also shown by Giri et al. (2023) [9] in papaya and Mithlesh et al. (2025) [14] in jackfruit, who recorded considerably increased shoot growth and seedling biomass which results as higher dry matter accumulation.

Fresh weight: Dry weight of shoot

The ratio of fresh weight to dry weight of shoot parameter of jackfruit was recorded at 90 DAS presented significant effect among the different pre-soaking seed treatments. The minimum ratio of fresh weight: dry weight of shoot (3.00) was recorded under the treatment T 2 (KNO 3 @1.0%) was statistically at par with the treatment T 6 (Thiourea @1.5%) and T 3 (KNO 3 @ 1.5%) having value of 3.01 and 3.13 respectively. The maximum ratio of fresh weight: dry weight of shoot (5.53) was observed under T 0 as presented in Table 3. The minimum ratio of fresh weight to dry weight of shoot recorded with KNO 3 @ 1.0% may be attributed to the beneficial impact of potassium and nitrate in improving seedling metabolism and dry matter accumulation. These processes enhance the accumulation of structural biomass in shoot tissues which resulting in higher dry matter relative to fresh weight (Taiz et al., 2015) [22] . Similar results have been reported by Aatla and Srihari (2013) [1] in mango, Bhavya et al. (2017) [5] in karonda and Rai et al. (2018) [18] in Khirni.

The observations on the survival percentage (%) of jackfruit seedlings under various pre-soaking seed treatments had a substantial impact on the survival percentage at 90 DAS and presented in Table 3. The treatment T 3 (KNO 3 @1.5%) had the maximum survival percentage (77.94%), followed by the treatment T 2 (KNO 3 @1.0%) had a survival rate of 73.56% in the present study. T 0 recorded the minimum survival percentage (46.47%). The higher survival percentage with KNO 3 @ 1.5% for 3 hours can be related to the favorable effects of nitrate and potassium in promoting vigorous root development, effective nutrient uptake and enhanced photosynthetic activity (Taiz et al. 2015) [22] . Rajamanickam et al. (2002) [19] found similar results in aonla, Bhavya et al. (2017) [5] in karonda and Mithlesh et al. (2025) [14] in jackfruit. Seed treatment with KNO 3 significantly boosted seedling survival percentage.

S.N.

Treatments Notations 1 Control T0 2 KNO 3 @ 0.5% for 3 hrs. T1 3 KNO 3 @ 1.0% for 3 hrs. T2 4 KNO 3 @ 1.5% for 3 hrs. T3 5 Thiourea @ 0.5% for 1 hr. T4 6

Thiourea @ 1.0% for 1 hr. T5 7

Thiourea @ 1.5% for 1 hr. T6 8

Cow urine @ 2% for 12 hrs. T7 9

Cow urine @ 3% for 12 hrs. T8 10

Cow urine @ 5% for 12 hrs. T9 11

Vermi wash @ 2% for 12 hrs. T10 12

Vermi wash @ 3% for 12 hrs. T11 13.

Vermi wash @ 5% for 12 hrs. T12

Note:

The superscript letter shows that the treatment means with the same letters are at par at 5% level of significance, whereas the means with different letters are significantly different at 5% level of significance. These letters have been affixed based on CD -value comparison of treatment means, DAS -Days After Sowing, -* this denotes to observation was not recorded on particular DAS. The superscript letter shows that the treatment means with the same letters are at par at 5% level of significance, whereas the means with different letters are significantly different at 5% level of significance. These letters have been affixed based on CD -value comparison of treatment means, DAS -Days After Sowing, -* this denotes to observation was not recorded on particular DAS. The superscript letter shows that the treatment means with the same letters are at par at 5% level of significance, whereas the means with different letters are significantly different at 5% level of significance. These letters have been affixed based on CD -value comparison of treatment means.

Conclusion

The present experiment revealed that impact of various presoaking seed treatments on germination and seedling growth of jackfruit (Artocarpus heterophyllus Lam.) under shed net condition. Among the different treatments, T 3 (KNO 3 @1.5%) constantly recorded the maximum values for germination percentage, height of seedling, diameter of seedling, number of leaves/seedling, fresh weight of shoot, dry weight of shoot and survival percentage. The treatment T 3 (KNO 3 @1.5%) closely followed by T 2 (KNO 3 @1.0%) throughout the study for most of the parameters. The superiority of KNO 3 @1.5% for 3 hours may be attributed to increased enzyme activity, seed reserve mobilization, respiration and rapid seedling establishment. Improved uptake of nutrients and photosynthetic efficiency resulted in rapid seedling growth. The control (T 0 ) observed the minimum values for all parameters. Based on these findings, T 3 (KNO 3 @1.5%) can be recommended as the most effective pre-soaking seed treatment for improving jackfruit germination and seedling growth under shed net conditions along with T 2 (KNO 3 @1.0%) functioning as a suitable alternative.

Acknowledgement

AcknowledgementsI am extremely grateful to my advisor, Dr. Prabhakar Singh,

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