Yield and quality of 'Pera' sweet orange grafted on different rootstocks under rainfed conditions/Producao e qualidade de frutos da laranjeira-'pera' em combinacao com diferentes porta-enxertos em condicoes de sequeiro

This study aimed to evaluate, under field conditions, different combinations between 'Pera' sweet orange and eight rootstocks: 'Rangpur' lime (RL), 'Volkamer' lemon (VL), 'Cleopatra' mandarin (CM), 'Sunki Maravilha' mandarin (SMM), 'Indio' and 'Riverside' citrandarins, and VL x RL ('Rangpur' lime)-010 and TH-051 hybrids. The soil water matric potential (Tm) was characterized for all scion-rootstock combinations at distance of 1.0m from the trunk at the plant row direction and depths of 0.25 m, 0.50 m 0.90 m in the dry and wet seasons. For two years, fruit production parameters and fruit quality were assessed. Differences of [PSI]m among scion-rootstock combinations were observed during the dry season (p [less than or equal to] 0.05). The lowest [PSI]m values for RL and the highest for TH-051 indicate the existence of different intrinsic mechanisms affecting the water extraction of each scion-rootstock combination. Rootstocks have influenced fruit yield and quality (p [less than or equal to] 0.05). The best combinations for fruit quality and production were sweet orange grafted on 'Riverside', 'Indio' and TH-051 rootstocks. Index terms: Citrus, matric potential, drought tolerance, rootstock. Este trabalho objetivou avaliar, em condicao de campo, combinacoes entre a copa laranjeira 'Pera' e oito diferentes porta-enxertos: limoeiro 'Cravo' (LCR), limoeiro 'Volkameriano' (LVK), tangerineira 'Cleopatra' (CLEO), tangerineira 'Sunki Maravilha' (TSKMA), citrandarins 'Indio' e 'Riverside', hibridos LVK x LCR (limoeiro 'Cravo')-010 e HTR (hibrido trifoliado)-051. Foi estimado o potencial matricial do solo ([PSI]m) para todas as combinacoes copa-porta-enxerto na posicao a 1,0 m do tronco, na linha de plantas, nas profundidades de 0,25 m, 0,50 m e 0,90 m, nos periodos secos e umidos. Durante dois anos, foram avaliadas a producao e a qualidade dos frutos. Foram observadas diferencas entre as combinacoes copa-porta-enxertos em relacao ao Tm (p [less than or equal to] 0,05) apenas para o periodo seco. O menor valor de [PSI]m para limoeiro 'Cravo' e o maior para o HTR (hibrido trifoliado)-051 indicaram a existencia de diferentes mecanismos intrinsecos de cada combinacao estudada que influenciaram na extracao de agua do solo, na posicao avaliada. Em relacao a producao e a qualidade de frutos, os porta-enxertos 'Riverside', 'Indio' e HTR (hibrido trifoliado)-051 destacaram-se como as melhores combinacoes com a laranjeira 'Pera'. Termos para indexacao: Citros, potencial matr