Tree morphology, yield and fruit quality of grapefruit cultivars on different rootstocks in Inceptisol

Influence of seven rootstocks on tree morphology, fruit quality and leaf physiology of 'Marsh Seedless' and 'Redblush' grapefruits was evaluated under subtropical north India. Rootstock effect on shoot relative elongation rate was found to be negligible. Both the cultivars showed higher fruiting density on rough lemon and Troyer citrange. 'Marsh Seedless' fruits did not differ much among rootstocks owing to sphericity. However, most spherical 'Redblush' fruits were recorded on Jatti Khatti (98.31%). Sour orange and Billikichlli induced very firm fruits in both the cultivars. 'Marsh Seedless' fruits on sour orange and Billikichlli developed maximum colour, whereas more bright and coloured 'Redblush' fruits were noticed on rough lemon, sour orange and Billikichlli. Moreover, while sour orange imparted the highest total phenol content (TPC) (490.23 mg Catechol/l juice) in 'Marsh Seedless' fruits, Billikichlli induced the highest (480.24 mg Catechol/l juice) in 'Redblush' fruits. 'Marsh Seedless' fruits with the highest naringin content (238.27 mu g/ml) were recorded on Troyer citrange and those of 'Redblush' (122.17 mu g/ml) on rough lemon. Billikichlli for 'Marsh Seedless' and Jatti Khatti for 'Redblush' were found desirable under moisture stress condition due to their lowest LWL (30.55 and 34.21%, respectively). Furthermore, highest leaf stomatal density in both 'Marsh Seedless' (0.48/mm(2)) and 'Redblush' (0.40/mm(2)) were reported on rough lemon.