Variability of the initial breeding material of cucumber by resistance to downy mildew and main traits
S. Stankevych, S. Bondarenko, L. Zhukova, V. Horiainova, L. Nemerytska, O. Afanasieva, I. Zhuravska, R. Mamchur, O. Romanov, T. Romanova, O. Bragin, I. Hordiienko, O. Gepenko, K. Katerynchuk, I. Kovalenko, O. Koval and S. Kyrenko
It was found that in samples from the resistant group, compared to the susceptible group, the difference between the average values of the reaction norm range for parameters such as the total cropping capacity is 4 times greater, the cropping capacity for the first decade of fruiting is 2.4 times, and the duration of the mass fruiting period is 2.3 times. It was determined that the initial breeding material (linear) of Gherkin-type cucumbers selected for resistance had an average range (Cv=10-20%) and a high range (Cv <20%) range of variability in 24 main valuable approbatory and economic traits, which are in demand in production, allowing mobile solutions to the main demands that consumers of the final product variety or hybrid make to breeders. It was found that the initial parental (male) form against the background of different resistances of the maternal one is the leading carrier and transmitter of the resistance trait in downy mildew to the hybrid generation F1 with an intermediate and positive character of its dominance. It was determined that a rise in the main parameters of the harmfulness of downy mildew under field conditions directly affects the decrease in cucumber indicators such as total cropping capacity (by 52-55%), commercial cropping capacity (by 47-56%), the duration of the fruiting period (by 37-42%), the number of fruits on the plant at the end of the first decade of mass fruiting (by 38%) changes the biochemical composition of fruit in the direction of increase in their dry matter content by 41-45%. With the help of correlation analysis among the 30 main economic and approbatory traits, a group of inert (21 pieces) was identified, with which the breeder can work individually, without caution that an artificial change in their characteristics in the breeding process for downy mildew resistance can negatively affect the final result of the breeding process for other traits.