01231nam a2200133 a 450000100080000000500110000800800410001910000220006024500990008226000260018130000090020749000210021652008600023716512931998-06-18       1980    bl uuuu  m   00u1 u    #d1 aLIMA, J. E. O. de  aFactors associated with excessive fruit drop of navel sweet orange Citrus sinensis (L.) Osbeck  aCalifornia: UFFc1980  a68p.  aTese de Mestrado  aSignificant navel fruit drop during the period between the end of Jun drop (mid-june) and legal maturity (late October) was observed during the 1978 and 1979 Florida seasons. Two distinct cycles were characterized. the first, from mid-June until mid-August was called "summer drop". The peak of summer drop occurred in early during full expansion of summer flush. A seoaration zone was found in the central axis of the fruit at the base of the secondary fruit, the navel. This zone became pronounced in about 16.5% of the fruit on the tree following the June drop and caused the secondary fruit to separate from the main fruit, turn yellow, and decay. Yellow navel fruit fell soon thereafter and represented the summer drop. It is possible that increased production of ethylene by the decaying secondary fruit stimulated the abscission of the primary one.