Frost resistance is associated with development of sour cherry (Prunus cerasus L.) generative buds

Spring frost is a limiting factor for yield and its stability in sour cherry. Shoots of sour cherry (Prunus cerasus L.) 7 cultivars were artificially frozen at -4 degrees C for 30 min at the Department of Orchard Plant Genetics and Biotechnology of Institute of Horticulture, Lithuanian Research Centre for Agriculture and Forestry. Dynamics of phenological phases was observed and probability of spring frost was evaluated. Cultivars were divided into two groups according to resistance to spring frost at different phenological phases. The first group consisted of plants that were most sensitive to frost in the fruit germ phonological phase. The second group consisted of the cultivars which were mostly sensitive in full bloom phase. It was established that resistance of sour cherry cultivars to spring frost is a combination of several biological components. Sour cherry resistance to spring frost depends on the level of development of generative buds during spring frost; stability of bearing depends also on the duration of most susceptible phenological phases and spring frost probability during these phases. Plants of 'Orkolija' cultivar were the most injured at -4 degrees C in full bloom phase as compared to other phonological phases and differed significantly compared to other cultivars studied. Stable bearing occurs in the sour cherry cultivars with short phenophases in which generative organs are most vulnerable to frost, and these phases occur when the probability of spring frost is low.