FLOWER BUD DEVELOPMENT OF APRICOT VARIETIES DURING PARADORMANCY

Flower bud development is an especially complex process from initiation to blooming.
Our main objective was to analyze paradormancy: the first stage of this process in our collection of varieties in the vicinity of Budapest, in Hungary.
The phenological and morphological factors of flower bud development are genetically determined; phenological aspects are influenced by the environmental effects.
The flower bud initials evolve between the end of July and mid-September.
The sepal, the petal, the ovary, the pistil and the stamen initials are distinguishable by late autumn.
Flower bud development is of great importance in yield, because the reproductive organs become more frost susceptible during the phenological period.
Slower flower bud development and later blooming decrease the risk of frost damage.

We have analyzed three varieties with different winter hardiness. ‘Ceglédi bíborkajszi’ is one of the most frost susceptible in our collection of varieties, when the flower bud differentiation started in early August, and all flower organ initials evolved early in September.
The flower bud differentiation of the most winter hardy variety, ‘Rózsakajszi C.1406’ started in the end of August, and all flower organs were noticed in mid-September. ‘Gönci magyar kajszi’ is a medium frost hardiness apricot variety; its phenological process is the transition between the two above-mentioned varieties.