Performance studies of apple cultivars on rootstock under cold dry temperate region of Lahaul and Spiti Valley, Himachal Pradesh

Introduction

Apple (Malus × Domestica Borkh) is an important temperate fruit crop in the world and belongs to family Rosaceous (Westwood, 1978) [16] The dry temperate climate of Himachal Pradesh is highly favorable for the cultivation of a wide variety of temperate fruits (Mehta et al., 2013) [6] . These fruits significantly contribute to enhancing farmers' incomes and strengthening the rural economy (Gangwar et al., 2008) [3] . Among them, apple cultivation has played a transformative role in improving the socio-economic conditions of rural communities, particularly in the High Hills zone of the state (Sharma et al., 2018) [13] . The area under apple cultivation expanded from 97,438 hectares in 2008-09 to 114,650 hectares in 2021-22 (Anonymous, 2022) [1] . Correspondingly, apple production reached 643,000 metric tonnes with a productivity of 5.62 MT in 2022 (Anonymous, 2022) [1] . However, despite the increase in total production driven by expansion of cultivated area, productivity has shown a declining trend over time (Awasthi et al., 2001) [2] . In Himachal Pradesh, the most widely cultivated apple varieties belong to the Delicious group (Jindal et al., 1992). Although apple production has shown a gradual increase, the lack of improved productivity and export-quality produce remains a significant concern for farmers in the district as well as the state. Apple cultivation is highly sensitive to climatic adversities (Rana et al., 2008) [8] , and farmers are increasingly experiencing the effects of climate change in their orchards. Beyond its direct impact on productivity, climate change has also intensified the incidence of pests and diseases, leading to further yield losses (Sharma, 2012; Gautam et al., 2013) [12,4] . Considering the economic importance of apple cultivation, the adoption of technologies that enhance both yield and fruit quality is essential (Mushtaq et al., 2018) [7] another reasons for low productivity is attributed to the non-descript seedlings stocks that are predominantly being used as rootstocks in apple plantations (Sharma and Kumar, 2006) [11] . It is therefore, very necessary to identify suitable rootstocks for improvement in apple cultivation. With high-density orcharding systems have been found to deliver higher early yields while sustaining productivity over the long term (Robinson and Hoying, 2011) [10] .

Materials and Methods

This study was conducted at Krishi Vigyan Kendra, Tabo, Lahaul and Spiti-II of Dr. YS Parmar University of Horticulture and Forestry, Nauni, Solan, H.P. for two years. The site is located at latitude of 32° 5.15´ North latitude and 78° 23.054´ East longitude on the globe with an altitude of 3243 m above mean sea level. The orchard was portrays the true dry temperate climate of the northwest Himalayas. There is virtually no rainfall during monsoon in the region because of rain shadow effect but in recent past few years there was unprecedented rainfall and snowfall has also been observed. The summer is very dry and short, while winter is long cold and freezing. The study was conducted in five varieties of apples viz., 'Super Chief/ EMLA-7, Scarlett Spur-II/EMLA-7, Oregon Spur-II/ EMLA-7, Red Fuji/ EMLA-7 and 'Coe Red Fuji/ EMLA-7 ' in 2020-2021. Four trees of each variety were randomly selected. The trees selected for this study were planted at a distance of 4 x3 m. (833 trees ha -1 ) with four replicates in a randomized block design. Growth parameters were recorded after the plants entered dormancy and before pruning. Average trunk diameter (mm), tree height (cm), tree spread (cm) and annual shoot extension growth (cm) were measured, following standard procedures. The spread of the tree was evaluated with the help of measuring the wood scale by recording the maximum canopy spanning the North-South and East-West directions. The fruit set was recorded three weeks after petal fall. The yield of fruits under different treatments was recorded at the time of harvest by weighing the total fruits on a top pan balance. The yield was expressed in kilograms tree -1 (kg plant -1 ). Fruits harvested from each selected plant were counted on each harvest and finally totaled to extract the average number of fruits plant -1 . Productivity was calculated on the basis of kg plant -1 and per unit area. The fruit's physical properties in terms of weight (g) and size (cm) were recorded by calculating the mean of ten fruits at final harvesting stage. The chemical characteristics of the fruits viz. TSS, bearing habit, fruit bearing fruit texture and pedicle length were recorded. The data recorded in 2020 and 2021 were pooled and statistical analysis was carried out accordingly.

Results and Discussion

Growth characteristics viz. shoot extension growth, trunk girth, plant height and plant spread, showed non-significant differences during the study as depicted in Table 1. The observations presented in the table 1 indicate noticeable variation among the cultivars for different vegetative growth parameters. Among all the cultivars on EMLA-7 rootstock, cultivar Oregon Spur-II recorded the maximum annual shoot extension growth (21.26 cm), followed closely by Coe Red Fuji (20.36 cm) and Red Fuji (19.78 cm), which can be considered at par with each other due to their comparable performance. The minimum shoot extension growth was observed in Scarlett Spur-II (15.36 cm), indicating relatively lower vigor compared to the other cultivars. In terms of trunk diameter, the highest value was recorded in Oregon Spur-II (43.36 mm), which was at par with Coe Red Fuji (41.99 mm) and Super Chief (40.89 mm), while the minimum trunk diameter was noted in Red Fuji (37.36 mm).With respect to plant height, Oregon Spur-II again exhibited the maximum height (219.36 cm), followed by Coe Red Fuji (211.36 cm), both of which were at par and significantly superior to the remaining cultivars. Super Chief (198.99 cm), Scarlett Spur-II (195.36 cm), and Red Fuji (193.12 cm) showed comparatively lower plant height and can be grouped as at par with each other, with Red Fuji recording the minimum value among them. In the case of plant spread in the East-West direction, the maximum spread was recorded in Oregon Spur-II (125.99 cm), followed by Coe Red Fuji (123.69 cm) and Red Fuji (119.36 cm), which were at par. The minimum spread was observed in Super Chief (80.36 cm), indicating a relatively compact growth habit. For plant spread in the North-South direction, Scarlett Spur-II recorded the maximum spread (112.87 cm), which was at par with Oregon Spur-II (105.96 cm), Coe Red Fuji (101.89 cm), and Super Chief (100.36 cm). The minimum North-South spread was observed in Red Fuji (93.55 cm), though it remained relatively close to the other cultivars. Overall, the results suggest that Oregon Spur-II and Coe Red Fuji consistently performed better across most vegetative growth parameters and were frequently at par with each other, whereas Scarlett Spur-II and Red Fuji showed comparatively lower performance in certain traits. Growth characteristics viz. shoot extension growth, trunk girth, plant height, and plant spread, showed non-significant differences during the study, which might be due to the heredity character of the variety, which increases the growth by increasing the uptake of nutrients from root to aerial part of the tree. [9,5,15,11,14] and is attributed to several factors like variety, soil, age and vigour of plant and orchard management practices being followed. Overall, the results clearly indicate that Oregon Spur-II performed superiorly across all fruit and yield parameters, while Super Chief and Scarlett Spur-II showed moderate but comparable performance. In contrast, Red Fuji consistently recorded the minimum yield and productivity, indicating comparatively lower performance under the given conditions.

References

1. Anonymous. Horticultural at a glance. Department of Horticulture, Himachal Pradesh, India; 2022.
2. Y.S. Parmar University of Horticulture and Forestry; 2001. p. 1-8.
3. Gangwar MP, Rai R, Karnwal MK, Singh YP, Kumar C. Evaluation of apple cultivars introduced from New Zealand at nursery stage. Progressive Horticulture. 2008;42:235-236.
4. Gautam HR, Bhardwaj ML, Kumar R. Current Science. 2013;105(12):1685-1691.
5. Kumar J, Verma HS. Performance of apple cultivars under low altitude conditions of Kullu Valley. Haryana Journal of Horticultural Sciences. 2001;30:139-142.
6. Mehta P, Thakur RK, Chauhan S. Production and marketing of apple fruit crop: a study premise to Shimla District of Himachal Pradesh. International Journal of Bio-resource and Stress Management. 2013;4(4):610-613.
7. Mushtaq R, Ashaq P, Mohammad, Tauseef ARHS, Raja MK, Sharma N, Nazir AK. Phenological features of four exotic apple cultivars on M9T 3 37 rootstock under high density plantation in North Himalayan region of India. Current Journal of Applied Science and Technology. 2018;29(6):1-5.
8. Rana RS, Bhagat RM, Kalia V, Lal H. Impact of climate change on shift of apple belt in Himachal Pradesh. In: ISPRS Archives XXXVIII-8/W3 Workshop Proceedings; Impact of Climate Change on Agriculture; 2008. p. 131137.
9. Rathore DS. Preliminary evaluation of genetic resources of apple. In: Chadha TR, Bhutani VP, Kaul JL, editors. Advances in research on temperate fruits. Proceedings of National Symposium on Temperate Fruits; 1984 Mar 15-18; Solan: Dr. Y.S. Parmar University of Horticulture and Forestry; 1986. p. 3-6.
10. Robinson T. Advances in apple culture worldwide. Revista Brasileira de Fruticultura. 2011;33(spl.):37-47.
11. Sharma DP, Chauhan JS. Performance of apple cultivars under cold desert conditions of North-Western Himalayas. Acta Horticulturae. 2008;772:199-201.
12. Sharma IM. In: Proceedings of the National Symposium on Blending Conventional and Modern Plant Pathology for Sustainable Agriculture. Indian Institute of Horticultural Research, Bengaluru; 2012.
13. Sharma R. Mapping of leaf nutrient status of apple (Malus domestica Borkh.) plantations, Northwestern Himalayas. International Journal of Chemical Studies. 2018;6(2):866871.
14. Singh J. Studies on the performance of some newly introduced cultivars of apple (Malus × domestica Borkh.) under high hill conditions of Kinnaur (H.P.) [thesis]. Department of Fruit Science, Dr. Y.S. Parmar University of Horticulture and Forestry, Solan; 2013. p. 1-56.
15. Sumrah MA, Nasir MM, Allah B, Nawaz MZ. Performance of some apple cultivars under sub-mountain climatic conditions. Sarhad Journal of Agriculture. 2000;16:393-395.
16. Westwood MN. Temperate zone pomology. San Francisco: W.H. Freeman and Co.; 1978. p. 300-303.