ENVIRONMENTAL FACTORS' INFLUENCE ON WALNUT FLOWERING

Abstract

Walnut culture has a long tradition in Romania, owing to favorable soil and weather conditions for walnut growing and fruiting, and also owing to its nutritional, curative and ornamental qualities. Recently, in order to build-up sustainable ecosystems, increasing attention is being paid to placing each genotype in ecological areas where ecological factors are closely similar to the biological requirements of the genotype. Although walnut is grown on vast areas in Romania, there are few areas where walnut yields are high and reliable. This demonstrates that as well as genetic characteristics, ecological factors have a decisive role in getting greater yields and quality. Research conducted on walnut has shown that the values of ecological factors, during flowering and pollination periods, have substantial effect on yield. Temperature is very important during the flowering period, especially during the opening of male flowers. This paper reports on the influence of temperature on flowering period and timing and on the degree of dichogamy in Romanian walnut cultivars.