Breeding Tests of Juvenile Factorial Hybrids of Populus tremula L.

Abstract

The aspen is known for its rapid growth, unpretentiousness to growing conditions, valuable timber and some other useful properties. The largest areas on the Eurasian continent are occupied by Populus tremula L. Unfortunately, it is susceptible to heart rot Fomes igniarius Fr., which is a significant drawback. Considering this drawback many scientists had carried out selection of rot-resistant stands and individual aspen trees in natural forests, and later proceeded to artificial hybridization. Besides different crossing options, factorial hybridization, in which several females are crossed with several males, is of interest. The resulting hybrids provide an opportunity to determine the best parental individuals or their pairs. Factorial hybridization of P. tremula in Russia was first carried out in the Central Chernozem region in 2015–2016 within the framework of international cooperation with the Institute of Forest Genetics of the Johann Heinrich von Thünen-Institute (Germany) under the MARussiA project. The purpose of the work was to carry out hybridization, create a field experiment on variety testing of the resulting hybrids and observe them to identify the best hybrids and parents. The hybrids were tested at experimental field sites in the Voronezh and Lipetsk regions. This paper presents the results of field testing at the Latnoye variety test plot in the Semiluky district of the Voronezh region (51°42’ N, 38°56’ E; total area – 2,160 m2). Survival of plants of different hybrid families in the 4-year field experiment ranged from 67 to 100 %; on average, it was 88 %. The average height of plants at this age in individual families varied from 349±38.7 to 510±30.0 cm, being on average 419 cm in the experiment. The average diameter at breast height (1.3 m) was 3.4 cm with fluctuations by families from 2.4 to 4.6 cm. The average size of species cylinders of aspen hybrids by families was 3.5 dm3 with fluctuations from 1.7 to 7.7 dm3. The general and specific combining abilities of the parental forms had been preliminarily found. The results have been compared with the results obtained in other countries. Performed laboratory and field experiments on hybridization of P. tremula L. in the Central Chernozem region will allow to determine the best parental forms and select a number of economically valuable hybrids.
Acknowledgements: The authors are grateful to their colleagues at the All-Russian Research Institute of Forest Genetics, Breeding and Biotechnology (Voronezh, Russia) for their help in cultivation of hybrids, development of the testing plot and maintenance thereof. Special thanks to Dr. M. Fladung and Dr. G. von Wühlisch from the Institute of Forest Genetics of the Johann Heinrich von Thünen-Institute (Großhansdorf, Germany) for creative collaboration on the MARussiA project (grant 68706, BLE) and to Prof. A.V. Pitukhin, Director of the PetrSU Institute of Forestry, Engineering and Construction Sciences, for signing an agreement for cooperation with the Institute of Forest Genetics of the Johann Heinrich von Thünen-Institute. The authors appreciate the letter of support for the relevance of research on the stated grant from the Forest Research Institute of Karelian Research Centre of the Russian Academy of Sciences.
For citation: Tsarev A.P., Tsareva R.P., Tsarev V.A., Laur N.V. Breeding Tests of Juvenile Factorial Hybrids of Populus tremula L. Lesnoy Zhurnal = Russian Forestry Journal, 2022, no. 5, pp. 9–20. (In Russ.). https://doi.org/10.37482/0536-1036-2022-5-9-20