Best of both worlds: hybrids of two commercially important pines (Pinus contorta × Pinus banksiana) combine increased growth potential and high drought tolerance

Abstract

Over 18 million hectares of lodgepole pine forests have been affected by a massive mountain pine beetle outbreak in western Canada. The ensuing need for reforestation compels forest managers to deploy more drought-resistant stock in anticipation of a hotter and drier future climate. Recent studies suggest that naturally occurring lodgepole pine × jack pine hybrids may be more drought-resistant than pure lodgepole pine. We used single nucleotide polymorphism (SNP) markers to determine the level of jack pine introgression present in the region J lodgepole pine seed orchard, in northwest Alberta, and identified six hybrid genotypes with 10-18% jack pine introgression for further study. We compared the performance of open-pollinated seedlings of lodgepole, jack and hybrid pines under well-watered and drought conditions in a greenhouse experiment. Seedlings were subjected to repeated drought cycles, withholding water for either two or three weeks. We found that hybrid pines grew significantly faster than lodgepole pine under well-watered conditions while retaining the high tolerance to prolonged drought exhibited by lodgepole pine seedlings, a particularly beneficial combination of traits during the critical stage of establishment. We therefore suggest the deployment of hybrid lodgepole pine as a strategy to promote adaptation to hotter and drier future climates.

Pinus contorta Douglas ex Loudon and climate change: A literature review of opportunities, challenges, and risks in European forests

“…Of the 12 conifer species studied, the growth of Pinus contorta, along with Pinus sylvestris, was least affected by precipitation and temperature and, for example, they achieved lower radial increment variability compared to native tree species (Vacek et al 2021). Moreover, researches showed that Pinus contorta × Pinus banksiana hybrids are more drought-resistant than monospecific Pinus contorta stands in relation to climate change (Bockstette et al 2021). In general, the consequences of climate change are negative for Pinus contorta stands growing in lowland areas, where warmer temperatures and extreme droughts lead to a decline in growth (McLane et al 2011).…”

Trichoderma longibrachiatum Inoculation Improves Drought Resistance and Growth of Pinus massoniana Seedlings through Regulating Physiological Responses and Soil Microbial Community

“…Especially in the karst area of Guizhou Province, because of the combined effects of the typical monsoon climate, specialized landform, and hydrogeological structure, the soils are prone to drought, which strongly impacts the growth of P. massoniana [4]. Currently, the predominant means of improving the drought tolerance of forest seedlings include genetic engineering, breeding for drought resistance, and chemical fertilizer application [5][6][7]. Such approaches may be slow acting 73.26 ± 1.74 mg•kg −1 , available phosphorus 17.39 ± 0.63 mg•kg −1 , and available potassium 326 ± 5.27 mg•kg −1 .…”