The control of floral initiation in lychee: A review

Abstract

In lychee (Litchi chinensis Sonn.), there is a strong correlation between flowering and the degree of dormancy prior to the normal period of floral induction. Low temperatures and moisture stress seem to restrict vegetative growth and promote floral initiation, but there are many exceptions and many examples of interactions of factors (crop load, tree nutrition, etc.). Both cincturing (ringing) and exogenous auxins have been shown to reduce vegetative flushing and increase flowering, but the results have not always been consistent. The best prospect for improving flowering appears to be through the selection of genotypes (probably those with low vigour) which flower under conditions which are generally warmer and wetter than those in its native environment in China. An alternative approach involves a critical study of manipulative techniques which restrict vegetative flushing and promote vegetative dormancy under non-inductive conditions, i.e. cincturing, applying growth retardants and withholding irrigation and fertilizers.