Trifoliate hybrids as alternative rootstocks for 'Valencia' sweet orange under rainfed conditions

Considering the low diversity of rootstocks in the Brazilian citrus industry, as well as in other important citrus production regions, here we investigated the yield, fruit quality, plant size and drought tolerance of 'Valencia' sweet orange [Citrus sinensis (L.) Osbeck] grafted onto eleven rootstocks in the northern region of São Paulo State, Brazil. The trial was installed with no supplementary irrigation. Various combinations (scion/rootstock) were planted in March 2007 and submitted to measurements of yield and fruit quality, canopy volume, yield efficiency, growth rate, and drought tolerance. We detected high yield in 'Valencia' sweet orange grafted onto “CNPMF 003” 'Rangpur' lime rootstock. Regarding other measurements, it was also attributed to two combinations high fruit quality of 'Valencia' sweet orange and to other three combinations satisfactory drought tolerance compared to two 'Rangpur' lime clones. 'Valencia' sweet orange trees grafted onto two rootstocks were suitable for high-density planting. As an alternative to 'Rangpur' lime, the 'Sunki' mandarin × P. trifoliata 'English' and 'C-13' “S” citrange rootstocks showed potential as rootstocks for 'Valencia' sweet orange in rainfed conditions.