Squash selection for powdery mildew resistance in the south of Russia

For pumpkin crops, powdery mildew is the most harmful disease. With its epiphytotics, economic losses can be 30% or more. The main way to combat this disease is the use of fungicides, but this is often not justified, because the pathogen can become resistant to them. In addition, in recent years ecological farming has been developing widely, in which the use of fungicides is not acceptable. Therefore, the creation of new varieties that are resistant to powdery mildew is one of the priority areas for the selection of pumpkin crops, including squash. The aim of the work was to create lines of squash resistant to powdery mildew, with other valuable features: precociousness, bush habit, attractive appearance of the fruit. To achieve the goal, it was necessary to solve a number of tasks: to determine the conditions favorable for the development of powdery mildew; select from the collection material samples with disease resistance; to carry out a reliable assessment of breeding offspring and select the most stable forms, consolidate and increase their stability with further selections in subsequent generations. The work was carried out in 2014-2018. on the Krymsk EBS, VIR Branch. The material for research was collectible and selection samples of squash. Studies have shown the effectiveness of sampling and squash lines for resistance to disease in open ground in the Krasnodar Region. Optimum weather conditions for the development of a pathogen in this region occur in early July and continue until September. In 2014-2015, eighty collection samples of the squash were studied, the most resistant of them were selected (F₁ Dessert, F₁ Е28Т00358, Line Ap3, F₁ Aleksandria). Annually, the active spread of the disease was observed on breeding material sown in summer, which contributed to the selection of lines with resistance to powdery mildew. As a result of research, squash lines (Ar3.1, Ds4, C1 x Ds4) with high resistance to powdery mildew were created. The direct dependence of the selection efficiency on resistance on the degree of natural infectious background was determined.

кабачок, мучнистая роса, линия, селекция, инфекционный фон, squash, powdery mildew, line, selection, infectious background