ABSTRACT
Citrus trees produce flushes throughout the year, but there are no criteria established for a precise shoot monitoring in orchards under tropical climate. Methods for quantification of flush dynamics would be useful for horticultural and pest management studies because different insect vectors feed and reproduce on flushes. We estimated the minimum number and distribution of trees for sampling and determined the flushing pattern over time in 'Valencia Late' orange trees grafted onto 'Swingle' citrumelo rootstock. Shoots within a square frame (0.25 m2) on two sides of the canopy were counted and classified by their phenological stage. The minimum number of samples was estimated using the mean number of shoots and area under the flush shoot dynamics (AUFSD). The temporal and spatial distribution analysis was performed by Taylor's power law and by multiple correspondence analysis (MCA). Additionally, a shoot maturity index (SMI) based on visual qualitative assessment of flushes is proposed. Considering the mean number of shoots, it was necessary to sample two sides of 16 trees to reach a relative sampling error (Er) of 25%, whereas by the AUFSD, only five trees were necessary to reach an Er of 10%. Flushes were predominantly randomly distributed over time and space. Testing eight transects, sampled trees should be distributed throughout the block, avoiding sampling concentration in a certain area. MCA showed that the west side and the upper sampling positions of trees were more likely to be associated with younger shoots. AUFSD and the evaluation of both sides of the canopy yielded a smaller number of trees to be assessed. The SMI was a reliable metric to estimate the shoot phenology of orange trees, and correlated well (R2 > 70%) with the mean number of shoots within the square frame. Therefore, SMI has the potential to make shoot monitoring in the field more practical.
Subject(s)
Citrus/growth & development , Animals , Brazil , Citrus/parasitology , Citrus sinensis/growth & development , Citrus sinensis/parasitology , Crops, Agricultural/growth & development , Disease Vectors , Ecological Parameter Monitoring , Host-Pathogen Interactions , Pest Control/methods , Plant Diseases/parasitology , Plant Diseases/prevention & control , Plant Shoots/growth & development , Sample Size , Tropical Climate , WeatherABSTRACT
Neste trabalho foi avaliado o desenvolvimento vegetativo, a produção e a qualidade de frutos da tangerina "Fairchild" [(tangerina "Clementina" (C. clementina Hort. ex. Tan.) x tangelo "Orlando" (C. paradisi Macf. x C. reticulata Blanco)] sobre os porta-enxertos limão "Cravo" (C. limonia Osbeck), citrumelo "Swingle" (P. trifoliata Raf. x C. paradisi Macf.), tangerina "Cleópatra" (C. reshni Hort. ex Tan.) e tangelo "Orlando" (C. reticulata Blanco x C. paradisi Macf.) em Bebedouro, SP, em experimento instalado em 1997. Plantas enxertadas em citrumelo "Swingle" apresentaram menor porte, maior produção acumulada de frutos nas safras 2005 e 2006, maior eficiência de produção (kgm-3) e menor índice de alternância de produção. A qualidade dos frutos não foi influenciada em função dos porta-enxertos. O citrumelo "Swingle" foi considerado cultivar porta-enxerto adequado para utilização com tangerina "Fairchild".
The vegetative development, fruit yield and quality of 'Fairchild' mandarin [('Clementine' mandarin (C. clementina Hort. ex. Tan.) x 'Orlando' tangelo (C. paradisi Macf. x C. reticulata Blanco)] was evaluated on 'Rangpur' lime (C. limonia Osbeck), 'Swingle' citrumelo (P. trifoliata Raf. x C. paradisi Macf.), 'Cleopatra' mandarin (C. reshni Hort. ex Tan.) and 'Orlando' tangelo (C. reticulata Blanco x C. paradisi Macf.) rootstocks in an experiment installed in Bebedouro, SP, Brazil in 1997. 'Fairchild' trees budded on 'Swingle' citrumelo were smaller, had higher cumulative yield in 2005 and 2006 seasons, higher yield efficiency (kgm-3), showed lower alternate bearing index. Fruit quality was not affected by the rootstock. 'Swingle' citrumelo was considered an adequate rootstock for 'Fairchild' mandarin.
