Genes controlling the vernalization requirement duration in winter wheat, Myronivska slava variety

Abstract

Bread wheat differs widely in adapting to different growing conditions. Creation of high-performance, plastic with high quality of wheat winter wheat varieties is the main task of the breeder. Important characteristics of winter wheat varieties are, in particular, the duration of the vinegar period and the sensitivity of plants to the length of the light day. The indicated parameters have an effect on the duration of stages of ontogenesis of plants, and therefore determine the ability of plants to adapt to the conditions of the winter period. It exists in the form of a number of forms - the winter, the yar, the hand pairs, which are the result of natural and artificial selection for specific environmental conditions. The type of development of wheat, winter or spring, is determined by the genetic system of locus Vrn, and the system of genes Vrd defines the duration of the
period of vernalization, which should pass plants for the transition to generative development. Sensitivity to the photoperiod is controlled by the Ppd gene system. It was determined that the dominant alleles of the two genes Vrd1 and Vrd2 predetermine the reduction of the vernalization period. During the early years of vegetation restoration, they can cause earlier plant depletion. The shortening of the vinegar period can provoke an earlier release of plants from rest in spring and winter during thawing, which contributes to reducing winter frost and, consequently, sometimes, and yield. Prolonged vitality needs are a prerequisite for achieving high frost resistance. Very early or too late sowing disrupts the process of vernalization and, as a result, adversely affects winter resistance and yield. Modern varieties are more likely to develop in the fall, so they are more sensitive to very early sowing dates. In view of this, the start of sowing for them should be 5-8 days later For research of put purpose were set such tasks a) To determine the vernalization requirement and photoperiodicity sensivity of sourcematerial b) to was to conduct hybridological analysis in hybrids trait of vernalization requirement.   As a result of the study, it was found that the vernalization requirement duration in breadwinter wheat. It has been found that the duration  of vernalization requirement of bread winter wheat variety Myronivska Slava is 40 days; according to the sensitivity to the photoperiod, the variety can be characterized as highly sensitive to the duration of the day (lengthening the growing season when growing plants in conditions of artificially shortened duration of the day is 11-15 days). The results of the hybridological genetic analysis involving special test lines in the genotype of the Myronivska Slava variety prove that the dominant allele of the Vrd2 gene reduces the duration of the vernalization period. On threshing out of wheat plants except genes that determine the vernalization requirement, a system of genes that to control the sensitivity of plants to the photoperiod (Ppd) has a significant influence. The bread winter wheat variety Myronivska Slava by genetically determined peculiarities of its development in the early stages of ontogeny, adapted to the natural conditions of cultivation in the Forest-Steppe of Ukraine. 
As we have found in previous studies, the presence of the dominant Vrd2 allele in the climatic conditions of the forest-steppe of Ukraine, due to the reduction of the vernalization period, may lead to some decrease in winter frost resistance of plants. However, strong photoperiodic sensitivity, which causes the delay of plant development in the short duration of light day during the preparation for the winter period, can compensate for the effect of the dominant allele Vrd2 and provide a sufficient level of winter resistance of plants. For the best preparation of the variety Myronivska Slava until the winter season, it is not necessary to sow its seeds too early in order not to provoke the passing of vernalization requirement before the beginning of the winter period and the transition to generative development with possible warming during wintering, and therefore possible damage to plants.