Results of Step Crosses in Selection of Pear Dwarfism Donors

Abstract

The article presents the results of 20 years of research on the implementation of a project to create pear varieties and complex donors of monogenously determined dwarfism (gene D) with high winter hardiness, group resistance to fungal diseases — scab (Venturia pirina Aderh., brownish (Entomosporium maculatum Lev.) and Septoria (Septoria piricola Desm.) and bright red color of fruits (gene C). The research was conducted according to generally accepted methods in the pear breeding gardens of Russian Research Institute for Fruit Crop Breeding in 2000-2019. The study objects were populations of hybrid pear seedlings obtained from targeted crosses of highly adaptive forms and hybrids of pears with descendants of the 4th generation of the Karlikovaya Zelyonaya variety (Nain Vert), heterozygous for the dwarfism gene (Dd) in the first stage, and hybrid seedlings from crossing a DK-2 donor with sources of good fruit taste in the second stage. The aim of the research was to identify winter-hardy complex donors of dwarfism for further use in breeding programs for the creation of intensive pear varieties. Seedlings were grown using conventional technology in a breeding garden on a plot with dark gray forest soil. As a result of research for further use in breeding as complex donors of dwarfism, winter hardiness, group resistance to fungal diseases and red color of fruits, 3 forms were selected in the second stage of crosses (DK-1-6-57, DK-1-674, DK-1-4-38). Their use in long-term innovative breeding programs for the creation of intensive pear varieties will allow to conduct rejections at the early stages of ontogenesis and thereby to reduce the volume of hybrid families by 2-4 times. These complex donors are briefly characterized.