PHENOLOGIC OBSERVATIONS ON WALNUT GENOTYPES

Abstract

Variation in the phenology of plants is one of the most sensitive ecological responses to climate change. Changes to species’ phenology can have a wide range of impacts on agriculture and forestry. Early bud-break is a limiting factor for commercial walnut growing like other species. Frequent late-spring frosts may damage flowers, buds, or nuts at the beginning of their development. For this reason it is very important to know phenology of cultivars. In this study, we determined phenology of 42 walnut genotypes which are grown under same ecological conditions. Date of terminal bud burst differed between mid march and april. The earliest burst of male flowers date was April 5 while the latest date was May 1. First female bloom of walnut genotypes/cultivars changed between April 7 and May 10. We observed that most of genotypes had protandry. In general fruit maturation occurred in the second part of September. Leaf drop started November 9 and finished December 15.