Deciphering the response of thirteen apple cultivars for growth, fruit morphology and fruit physico-chemical attributes during different years

Apple cultivation is one of the most significant means of subsistence in the Kashmir region of the northwestern Himalayas. It is considered as the backbone of the region's economy. Apple cultivation in the region is dominated by a late maturing cultivar “Red Delicious” which usually on maturity causes glut in the market. In order to bring new cultivars in the cultivation, and to expand the maturity season, it is necessary to evaluate the new cultivars on fruit physico-chemical attributes which ultimately decide the market rates before recommending to farmers for cultivars adoption. Therefore, the current study was carried out to evaluate thirteen apple cultivars on physico-chemical attributes over two years, 2017 and 2018 under agro-climatic conditions of Kashmir region The results revealed that cultivars differed significantly in terms of physico-chemical properties. Cultivars with the highest and lowest values for initial fruit set, fruit drop, final fruit retention, and fruit firmness in 2017 did not follow the same trend in 2018. During 2017 and 2018, cultivar Mollie's Delicious possessed the highest fruit length (72.39 mm and 81.45 mm), fruit diameter (81.18 mm and 84.14 mm), and fruit weight (205.85 g and 247.16 g), whereas cultivar Baleman's Cider had the lowest values (50.76 mm and 52.83 mm, 60.10 mm and 62.08 mm, and 71.46 g and 86.94 g), respectively. The harvesting dates were quite spread out during both years of study. Cultivar Mollie's Delicious was harvested the earliest in both years, on August 5th, 2017 and August 8th, 2018. Cultivar Fuji Zehn Aztec was the last cultivar harvested in 2017 on October 2 and in 2018 on October 5. The maximum number of seeds per fruit was noticed in the cultivar Mollie's Delicious (8.34 and 8.71) during both 2017 and 2018, respectively. Cultivar Starkrimson had the fewest seeds per fruit in 2017 (7.11) and 2018 (7.42). Cultivar Baleman's Cider had the highest acidity in 2017 (0.63%) and 2018 (0.52%). In both 2017 (0.25%) and 2018 (0.23%), the Adam's Pearmain cultivar was the least acidic. Cultivar Allington Pippin (16.13 °Brix) and Red Gold (16.73 °Brix) had the highest TSS in 2017 and 2018, respectively, whereas Vance Delicious (12.30 °Brix) and Top Red (10.78 °Brix) had the lowest TSS in 2017 and 2018, respectively. The cultivars Mollie's Delicious and Red Gold had the highest total sugars (11.33 and 11.40%) in 2017 and 2018, respectively. Cultivar Baleman's Cider had the lowest total sugars (9.82%) in 2017 while Top Red (9.78%) in 2018. The cultivar Vance Delicious had the highest ratio of leaves to fruits in 2017 (55.44) and for Shalimar Apple-2 in 2018 (49.65). In 2017, cultivars Fuji Zehn Aztec (29.26) and Silver Spur (24.51), had the fewest leaves per fruit. The highest leaf chlorophyll content was recorded in cultivar Shireen (3.50 and 3.57 mg g(−1) fresh weight) during the years 2017 and 2018, respectively. Cultivar Baleman's Cider had the lowest leaf chlorophyll content (2.15 mg g(−1) fresh weight) during 2017, while cultivar Allington Pippin (2.09 mg g(−1) fresh weight) had the lowest leaf chlorophyll content in 2018. The cultivars Fuji Zehn Aztec, with a yield efficiency of 0.78 kg/cm(2) and Silver Spur with a yield efficiency of 1.14 kg/cm(2) were the most yield efficient during the years 2017 and 2018, respectively. Cultivar Shalimar Apple-2 was least performing with yield efficiencies of 0.05 and 0.07 kg/cm(2) during 2017 and 2018, respectively.The findings suggest that cultivar Mollie's Delicious commercially matures first and has the highest fruit length, diameter, and weight; hence, it can be a good option for cultivation so as to fetch the maximum price in the market when other cultivars are still maturing. Shalimar Apple-2 is precluded for cultivation due to least yield efficiency, whereas cultivars Fuji Zehn Aztec and Silver Spur are recommended to farmers for their higher yield efficiency.