Screening of Amla (Phyllanthus emblica L.) varieties for salinity tolerance by growth and physiological parameters

Introduction

Amla (Phyllanthus emblica L.) also known as Aonla or Indian gooseberry is native to tropical South-Eastern Asia. It is a highly valued fruit crop renowned for its exceptional medicinal and nutritive properties mentioned in ancient Indian mythological literatures like Vedas, Shivpuran, Askandhpuran, Padmapuran, Ramayana, Kadambari, Charak Samhita, Sushrut Samhita, etc., considered as Amrit Phal (life giving fruit) (Bhat et al., 2019) [2] . It is the second highest natural source of Vitamin C (400 to 1500 mg/100 g fruit pulp) (Saini et al., 2019) [16] . With a total area under cultivation of 92,000 ha India produced 1,046 thousand metric tonnes (MT) of gooseberries. The major amla producing states include Uttar Pradesh, Madhya Pradesh, and Tamil Nadu accounting for 75% of the total gooseberry production in India (NHB, 2022) [12] . NA-6, NA-7, NA-8, NA-9, NA-10, Banarasi, Chakaiya, Krishna, Francis, Kanchan, Gujarat-1, Gujarat-2, Goma Aishwarya, Neelam, Desi, Bansi red, and Laxmi-52 are some of the common varieties cultivated in various parts of India (Tewari et al., 2023) [18] . Globally, salt affected land is expanding (Mandal et al., 2018) [9] , with predictions suggesting that 40% to 50% of the Earth's surface may face drought and salinity stress by 2025 (Martinez et al., 2024) [11] . In India, approximately 6.73 million hectares are left barren due to salinity, heavily impacting several states (CSSRI, 2020) [5] . Salinity induces osmotic stress, restricting water uptake and leads to accumulation of toxic ions. It causes stunted growth, poor yield and quality. It leads to overproduction of Reactive Oxygen Species (ROS) resulting in oxidative stress that damages vital cellular structures. Tolerant fruit crops use various physiological and biochemical defense mechanisms to overcome these. They include osmotic adjustment via the accumulation of compatible solutes such as proline to maintain turgor pressure and activation of antioxidant enzymes (peroxidase, catalase, superoxide dismutase) to scavenge excess ROS (Patel et al., 2011) [13] . Since conventional management by using chemical amendments are costly and temporary. Cultivation of salt tolerant fruit crops presents a sustainable alternative as amla is identified as a tolerant fruit crop capable of thriving in saline soils. Although amla have significant potential for cultivation in saltaffected areas, the specific mechanisms of tolerance vary markedly among different intra-specific varieties. There remains a crucial knowledge gap regarding the comparative salinity tolerance of these specific cultivars. To address this, the present study five prominent amla varieties under varying controlled levels of salinity stress to elucidate the mechanisms and most suitable tolerant cultivars.

Materials and Methods

The present investigation was carried out at North Farm within the Division of Horticulture, Karunya Institute of Technology and Sciences (KITS) located in Coimbatore, Tamil Nadu, India at at 10.9362° N, 76.7441° E during 2025-2026. Experiment was conducted in five varieties of amla. It was replicated thrice with five plants per replications in a Factorial Randomized Block Design (FRBD) with twenty treatment combinations.

Materials collection & preparation

Eight months old amla seedlings of five different cultivars (Krishna, Kanchan, Chakiya, NA-7 & Coimbatore Local) collected from Periyakulam and Velliangiri. It was transplanted in November 2025. Leaf samples were collected and analysed in March 2026 after three months from date of imposition. Salinity levels were maintained following procedure given by Meena et al. (2019) [10] adding NaCl 2 , the equivalent weights are multiplied by the number of equivalents and dissolved in one litre per pot. Example, for 8 dSm -1 or 40 meq /litre of NaCI 2 = 58.5 x 80 = 4,680 mg/l.

Factor details

Treatment details

Notations Treatment details

Evaluation of physical and chemical properties Plant height was measured from the base of the plant to the tip of the terminal bud using a standard meter scale. The observations were recorded in centimetres, and the average was calculated for each treatment. Plant spread was recorded using measuring tape. The maximum width of the plant canopy that is widest point and perpendicular width was taken. The average was recorded as plant spread. Stem diameter was measured with digital vernier calliper and average calculated. Number of branchlets per plant was counted manually from the branches that originated from main axis. Leaf area was taken using Leaf Area Meter 211. Relative water content was calculated by the following formula given by Liu et al. (2019) [3] . The EC (Electrical Conductivity) of soil was maintained in all pots by using an EC meter (Labtronics ISO 9001 -2008 certified). The factorial and interaction effects were evaluated using analysis of variance (ANOVA). The differences between treatment means have been analysed by using the least significant difference (CD @ 5%) test.

Results and Discussion

Plant height and plant spread

The data in table 1. showed that the varieties and salt concentration significantly affected the plant height and plant spread. The highest (92.71 cm) and the lowest (52.83 cm) plant height were found in V 2 C 1 and V 1 C 4 , respectively. The highest (59.79 cm) and the lowest (33.28 cm) plant spread were also recorded in V 2 C 1 and V 1 C 4 , respectively. These results were related to those obtained by Rao and Singh, (2006) [14] in Chakiya variety of Amla. They reported that the lowest plant height (151.40cm) and plant spread (43cm) were found during the highest salinity level of 15 dS m -1 .

Stem diameter and number of branchlets

As per data in table 1. there is significant effect of varieties and salinity concentrations on stem diameter and number of branchlets. The highest (1.74 cm) and lowest (1.26 cm) stem diameter were found in V 2 C 1 and V 1 C 4 , respectively. The highest (51.37) and lowest (21.13) number of branchlets recorded are V 2 C 1 and V 4 C 4 , respectively. These results agreed with those obtained by Shukla and Pathak, (1999) [17] in different varieties of Amla. They revealed that the stem diameter (Krishna-1.57cm and Kanchan-1.21cm) and number of branchlets per plant (Krishna-125.25 and Kanchan-85) were found under salinity stress.

Leaf area, leaf length and chlorophyll content

According to the data in Table 2. there is significant effect of varieties and salinity concentrations on leaf area, leaf length and chlorophyll content. The highest (0.486 cm 2 ) and lowest (0.246 cm 2 ) leaf area were found in V 2 C 1 and V 1 C 4 , respectively. The highest (1.213) and lowest (0.547 cm) leaf length were found in V 2 C 1 and V 1 C 4 , respectively. The highest (1.213 mg g -1 ) and lowest (1.63 mg g -1 ) chlorophyll content were found in V 2 C 1 and V 1 C 4 , respectively. These findings were related to Rao et al. (2009) [15] in Chakiya variety of Amla. They reported that the highest (1.87 mg g -1 ) and the lowest (1.72 mg g -1 ) chlorophyll content were found in the lowest (0.8 dS m -1 ) and the highest (15 dS m -1 ) salinity.

Relative water content and plant survival

The data in Table 2. showed that varieties and salinity concentration have significant effects on relative water content and survival. The highest (51.37 per cent) and lowest (21.13 per cent) relative water content were recorded in V 2 C 1 and V 4 C 4 , respectively. Figure 1. illustrated that the survival percentage was significantly affected by varieties and salinity concentration. The highest (92.74 per cent) and lowest (56.27 per cent) survival rate was found in V 2 C 1 and V 1 C 4 respectively. These results related with those reported by Bajpai et al. (2017) [1] in Mango. They concluded that the highest (95.16 per cent) and the lowest (85.85 per cent) relative water content were found in control and salinity stressed plants respectively. Similar results have been found that reduced morphological and physiological parameters in response to increased salinity in pomegranate (Liu et al., 2019) [3] , grape (Fozouni et al., 2012) [4] , gooseberry (Joshi et al., 2022) [6] , date palm (Kharusi et al., 2017) [7] , passion fruit (Lima et al.,2023) [8] , citrus (Patel et al., 2011) [13] .

Acknowledgement

AcknowledgementThe authors thank the Division of Horticulture, School of Agricultural Sciences, Karunya Institute of Technology and Sciences, Coimbatore for their help with laboratory activities for this research work. DisclaimersThe views and conclusions expressed in this article are solely those of the authors.

References

1. Bajpai A, Muthukumar M, Bajpai Y, Anand S, Ahmad I, Das A. Salinity induced growth, physiological and gene expression responses in polyembryonic mango cultivars. Green Farming. 2017;8(5):1076-1080.
2. Bhat P, Umale H, Lahankar M. Amalaki: a review on functional and pharmacological properties. Journal of Pharmacognosy and Phytochemistry. 2019;8:4378-4384.
3. Liu C, Zhao X, Yan J, Yuan Z, Gu M. Effects of salt stress on growth, photosynthesis, and mineral nutrients of 18 pomegranate (Punica granatum) cultivars. Agronomy. 2019;10(1):27-382.
4. Fozouni M, Abbaspour N, Baneh HD. Leaf water potential, photosynthetic pigments and compatible solutes alterations in four grape cultivars under salinity. Vitis. 2012;51(3):147152.
5. ICAR-Central Soil Salinity Research Institute. Annual report 2022-23. 2023.
6. Joshi S, Trivedi D, Jain A, Mishra A. Effect of salinity on seed germination, soil analysis, water content, membrane leakage, anatomy and stomatal index and growth of Phyllanthus emblica Linn. NeuroQuantology. 2022;20(18):1041-1054.
7. Kharusi LA, Assaha DVM, Al-Yahyai R, Yaish MW. Screening of date palm (Phoenix dactylifera L.) cultivars for salinity tolerance. Forests. 2017;8(4):136-145.
8. Lima GS, Souza WBB, Paiva FJS, Soares LAA, Torres RAF, Silva STA, et al. Tolerance of sour passion fruit cultivars to salt stress in a semi-arid region. Revista Brasileira de Engenharia Agrícola e Ambiental. 2023;27(10):785-794.
9. Mandal S, Raju R, Kumar A, Kumar P, Sharma PC. Current status of research, technology response and policy needs of salt-affected soils in India: a review. Journal of the Indian Society of Coastal Agricultural Research. 2018;36:40-53.
10. Meena BL, Kumar A, Mann A, Kaledhonkar MJ. Development and measurement of soil salinity for pot experiments. ICAR-Central Soil Salinity Research Institute; 2019.
11. Martinez JP, Sagredo B, Moreno MA. Using rootstocks in crops and fruit trees to mitigate the effects of climate change and abiotic stress. Frontiers in Plant Science. 2024;15:1479317.
12. National Horticulture Board. Area production statistics 2022. 2022.
13. Patel SK, Dubey A, Srivastav M, Singh A, Dahuja A, Pandey RN. Effect of NaCl in the irrigation water on growth, antioxidant enzyme activities, and nutrient uptake in five citrus rootstocks. Journal of Horticultural Science and Biotechnology. 2011;86:189-195.
14. Rao VK, Singh HK. Response of sodicity and salinity levels on vegetative growth and nutrient uptake of aonla genotypes. Indian Journal of Horticulture. 2006;63(4):359364.
15. Rao VK, Rathore AC, Singh HK. Screening of aonla (Emblica officinalis Gaertn.) cultivars for leaf chlorophyll and amino acid under different sodicity and salinity levels. Indian Journal of Soil Conservation. 2009;37(3):193-196.
16. Saini AK, Chauhan RS, Kumar A, Singh N, Kumar S. Evaluation of the varieties of Indian gooseberry for resistance against Penicillium islandicum. International Journal of Current Microbiology and Applied Sciences. 2019;8(9):2086-2089.
17. Shukla AK, Pathak RK, Tiwari RP. Effect of salt stress on growth and leaf nutrient status of aonla (Emblica officinalis Gaertn) cultivars. Indian Journal of Horticulture. 1999;56(1):37-40.
18. Tewari R, Kumar V, Sharma HK. Thermal and nonthermal processing of an underutilized fruit Emblica officinalis (amla): a sustainable approach. Food and Function. 2022;13(24):12534-12555.