Variability of reproductive development of half-sibs of Pinus Sibirica Du Tour

Abstract

Selection of Pinus sibirica Du Tour plus trees by seed productivity, breeding of half-sibs, characterized by an abundance of cones and pollen, serve as the basis for the creation of high-yielding target plantations. The aim of the research was to select families with a large percentage of early reproductive development's trees, and specimens with a lot of cones and shoots with male inflorescences. Also, to select specimens in different families of Pinus sibirica Du Tour plus trees by early reproductive development, taking into account the formation of cones and pollen. The subject of the study was the seed progeny of Pinus sibirica Du Tour trees at biological age of 31-35 years, grown on the territory of the arboretum of Reshetnev University, the site «Prodolzhenie geoshkoly» (N 55.9666666667, E 92.6166666667, 287 meters above sea level). Initially, five plus trees growing in Irkutsk (60/24) and Novosibirsk regions (98/62, 102/66, 106/70 and 110/74) for reproduction among certified plus trees by seed productivity were selected. The growing conditions and indicators of plus trees from the certificate drawn up by the commission during their certification are given. Cones from these trees were collected, then seeds were sown and planting material was grown, which was transplanted to the site of the arboretum of Reshetnev University. In 2018, 2021 and 2022, the number of cones and microstrobiles in early reproductive development semis by using binoculars was determined. The variability by early reproductive development of half-sibs in the formation of cones both between families of plus trees (7.8-25.3 psc.), and within families (60/24 – 2-22 psc.; 98/62 – 2-115 psc.; 102/66 – 4-45 psc.;106/70 – 1-54 psc.; 110/74 – 1-15 psc.) is noted. The selection of specimens by the size of the cones was not carried out. Some specimens formed both cones and pollen: 82-7, 85-10 and 87-13 in the family of the plus trees 60/24; 72-11, 79-2, 79-3, 79-4, 79-8, 80-3, 81-4, 85-22 (family 98/62); 83-1,83-6, 83-9, 84-2, 84-4, 86-9, 86-1 (family 102/66); 78-3, 78-9, 81-8, 81-9, 81-10, 85-19 (family 106/70); 79-9, 84-12, 86-5 (family 110/74). Selected specimens have a huge value and can be widely used in their vegetative reproduction and the creation of high-yielding plantations of early reproductive development.