Growth parameters and resistance to Sphaerulina musiva-induced canker are more important than wood density for increasing genetic gain from selection of Populus spp. hybrids for northern climates

Marzena Niemczyk,Barb R Thomas

doi:10.1007/s13595-020-0931-y

Marzena Niemczyk, Barb R Thomas

Open Access

https://doi.org/10.1007/s13595-020-0931-y

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Abstract

Key messageNew genotypes of hybrid poplars from theAigeirosandTacamahacasections have great potential for increasing genetic gain from selection. The most promising traits are associated with productivity and resistance toSphaerulina musiva-induced canker while wood density can be selected for secondarily. A minimum age of 8 years is reliable to select fast-growing resistant clones in northern climates.ContextProductivity, wood density, and disease resistance of hybrid poplar clones are important traits when selecting for cultivation at an industrial scale.AimsWe studied 1978 hybrid poplar clones from 63 families, bred from poplars native (Populus balsamifera and Populus deltoides) and non-native to Canada from the Aigeiros and Tacamahaca sections, to improve economically important traits for plantations in northern Alberta.MethodsGenetic parameters for diameter at breast height (DBH), height, resistance to Sphaerulina musiva-induced canker, and wood density were determined up to age 10.ResultsA mean annual increment of 16.5 m3 ha−1 year−1 was achieved at age 10 in the best-performing clones. The potential genetic gain for DBH, height, and canker resistance, 37%, 26%, and ~ 13%, respectively, was achieved when selecting the top 10% of the tested clones. The genetic effect for wood density was weak. The age-age genetic correlations identified age eight as a reliable selection age.ConclusionThe new hybrid poplar clones tested exhibited great potential for tree improvement. The next phase of selection should test a reduced number of clones on different site types, identifying stable clones for productivity and resistance, while wood density can be selected for secondarily. In northern regions, a minimum age of 8 years is reliable to select fast-growing resistant clones for commercial deployment.

Highlights

The application of tree improvement in breeding programmes allows, in a broad sense, an increase in yields and value of plantations, while helping to meet the rising demand for forest products, and in some regions of the world, thereby reducing the pressure on natural forests
The performance results together with large variation in growth parameters, production, and resistance to Sphaerulina musiva-induced canker, show that through selection, considerably higher genetic gain is possible with higher yielding and more resistant clones than those currently used in this region
This study revealed great potential for tree improvement based on an extensive genetics trial of new hybrid poplar clones tested for deployment in northern climates

Summary

Introduction

The application of tree improvement in breeding programmes allows, in a broad sense, an increase in yields and value of plantations, while helping to meet the rising demand for forest products, and in some regions of the world, thereby reducing the pressure on natural forests Such programmes aim at developing genetically improved varieties in an economically efficient manner by maximizing genetic gain per unit time at the lowest possible cost (White et al 2007). The genetic resources of poplars are commonly managed as a source of fibre in the pulp and paper industry, and more recently in biomass and biofuel production, carbon sequestration, and phytoremediation (Balatinecz and Kretschmann 2001; Zalesny Jr. et al 2016) For these reasons, tree improvement programmes using hybrid poplars have been developed in several countries in North America and Europe. The development of these correlations can be used to support decisions regarding the youngest age possible at which to make the selection for a given trait (White et al 2007)

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