| Abstract [eng] |
Sour cherry (Prunus cerasus L. (sin. Cerasus vulgaris Mill., Prunus vulgaris Schur)) is widely grown stonefruit tree in Lithuania. Productivity of sour cherry orchard depends on many tightly related factors. It's know that negative temperature and spring frosts are important factors determinating plant productivity. These factors must be considered in plant breeding. Risks of extreme temperatures, humidity deficiency and spring frosts increases due to climate change. Plant reaction to climate change depends on plant species, cultivar and on biotic or abiotic factors. Spring starts earlier and suddenly during past years, thus vegetation of cherries starts earlier. However, probability of plant damage to spring frosts increases due to earlier vegetation, because plants are susceptible to negative temperatures due to loss of the predictive and consequential (secondary) dormancy. The aim of the research was to evaluate DNA polymorphism of sour cherry cultivars with different resistance to spring frosts, to characterize nature of phenological phase changes, to evaluate biochemical characteristics of sour cherry resistance to spring frosts formation by analysis of changes in carbohydrate amount and composition in generative organs and fruit ovaries at different phenological phases, and to evaluate changes in gene expression levels of galactinol synthase and raffinose synthase during flower development. It was established, that specific rhythm of phenological development is characteristic to different sour cherry genotypes. This enables to prepare selection schemes of genotypes with shorter phenological phases at which generative organs or flowers are the most susceptible to spring frosts, thus minimizing risk of frost injury. Differences in levels of galactinol synthase and raffinose synthase gene expression and related differences in amount of raffinose family carbohydrates in generative organs were identified. This enabled their use as molecular markers of resistance to frosts for selection of hybrids during the first year of growth. DNA fragments specific to spring frost resistance may be useful to establish breeding programs dedicated to development of sour cherry cultivars resistant to spring frost. |
