Horticultural performance of 'Tahiti' lime selections grafted on 'Swingle' citrumelo under irrigated and non-irrigated conditions Since the '90s, 'Tahiti' lime (Citrus latifolia (Yu. Tanaka) Tanaka) has increased its importance in the Brazilian agribusiness with economic and social impacts, due to higher fruit value recorded both on domestic and international markets. Genetic diversity of this species is restricted, and in Brazil, most of the commercial orchards are predominantly based on "IAC 5" and "Quebra-galho" selections. Currently, new selections are available for scion diversification. Nonetheless, technical information about these materials is very limited, thus restricting the studies on scion diversification. Besides the low diversification of scions, most of the orchards are established onto the 'Rangpur' lime (Citrus limonia Osbeck), because of higher yield and tolerance to water deficit induced by this rootstock. "IAC 5" and "Quebra-galho" selections grafted onto the Rangpur lime result in large-sized plants of low longevity, because of their high susceptibility to Phytophthora gummosis (Phytophthora spp.), and the endemic presence of severe Citrus Tristeza Virus strains and the Exocortis Citrus Viroid. Restricted scion and rootstocks diversification increase the risks associated with outbreaks of new and more severe diseases and pests that threaten the whole 'Tahiti lime production chain. This study evaluated the horticultural performance of five 'Tahiti' lime selections grafted on 'Swingle' citrumelo [Citrus paradisi Macfad. cv. Duncan x Poncirus trifoliata (L.) Raf.], in Bebedouro, São Paulo State, Brazil. Due to constraints for the commercial use of 'Swingle' citrumelo as rootstock in environments under prolonged water deficit conditions, two trials were conducted for evaluation of 'Tahiti' lime selections under irrigated and non irrigated conditions. The following 'Tahiti' lime selections were studied: "IAC 5", "IAC 5-1", "CNPMF/EECB", "CNPMF 2000" and "CNPMF 2001". The experiment was installed in March 2005 and the evaluations were performed between 2007 and 2011, involving the following variables: plant growth, yield, yield efficiency, fruit quality, photosynthesis rate and leaf water potential in both irrigated and non-irrigated trials. In addition, plant water deficit tolerance, stomatal conductance, transpiration rate and water use efficiency were evaluated in the non-irrigated trial for selecting suitable selections for non-irrigated plantings. Data obtained in the irrigated and non-irrigated trials were submitted to individual and joint analyses of variance, and the comparisons among means were performed by Duncan test (P<0.05). The "CNPMF/EECB" selection had larger cumulative fruit yield and yield efficiency both in the irrigated and non-irrigated plantings. In the irrigated trial, the "CNPMF/EECB" selection presented larger offseason fruit yield. The "IAC 5-1", "CNPMF/EECB", "CNPMF 2000" and "CNPMF 2001" selections had larger tree size than the "IAC 5" selection, both in the irrigated a...
