ABSTRACT
Vitis Vinifera has a relatively short juvenile phase. The imperfect flower forms are more common in the American Vitis species than in V. vinifera. Both male and female flowers are widely known in wild species and in cultured cvs. The floral induction of grapevines depends on both endogenous and environmental conditions. Neither photoperiod nor light intensity is a critical factor in floral induction of grapevines as long as light is not a limiting factor for normal vegetative development. The flowering of grapevines is independent of daylength, light intensity, and RH but highly dependent on temperature. Thus, all environmental conditions which have an effect on the temperature will have an indirect effect on flowering. Various growth promoters and inhibitors were found to affect flowering. These effects on the time of flowering are indirect, as they mainly affect the time of bud opening in the spring, as do favorable or unfavorable environmental conditions at that time.
