Phenological Variation in Bluebunch Wheatgrass (Pseudoro-Egneria Spicata): Implications for Seed Sourcing, Harvest, and Restoration

To reduce maladaptation in cultivated seed lots, seed transfer zones (STZs) have been developed for grasslands and other habitats using morphological traits and phenological measurements that only capture the first day of events such as flowering and seed ripening. Phenology is closely linked to plant fitness and may affect genetic loss during harvests of seed raised for ecological restoration. Here, we measured the detailed phenologies of 27 populations from six STZs of bluebunch wheatgrass (Pseudoroegneria spicata) (Pursh) Á. Löve (Poaceae) raised in a common garden to test whether existing STZs created using a combination of plant morphology and “first-day” phenological measurements adequately capture population-level variation in season-long, detailed phenologies. We also used detailed phenologies to test whether genetic losses may occur during single-pass harvests of commercial seed. Mixed and random effect models revealed differences in detailed reproductive phenology among populations within two of six STZs. The number of individual plants within an STZ not producing harvestable seed during peak harvest levels indicated that 10–27% of individuals from a seed lot could be excluded from a single-pass harvest. Although our findings generally support current STZ delineations for P. spicata, they point to the possible precautionary importance of sourcing from multiple populations and harvesting with multiple passes when resources permit.

The influence of seed transfer distance on the growth of Calotropis procera (ait) provenances in dry lands of South Eastern Kenya

In a study to domesticate the species Calotropis procera, for wool production in drylands, investigations were done to determine the effects of seed transfer distance on the growth of the species in a typical farm setting. The objectives of the research were to determine the growth of three provenances of C. procera and to determine the influence of seed transfer distance on the growth parameters. Diameter and height data were used to generate horizontal and vertical growth curves respectively and further subjected to Duncan Multiple Range Test (DMRT) to isolate existence of significant differences across the three provenances. Pearson correlation analysis was used to establish existence of relationships across the growth parameters. Results showed that C. procera is a multi-stemmed plant. Duncan Multiple Range Test (DMRT) showed no significant statistical differences (p<0.5) in diameter growth though Pearson correlation analysis, showed strong positive correlations (Pearson, p<0.01) between branching and DBH Test of homogeneity of variances showed significant statistical differences (p<0.5) in vertical growth The study concluded that C. procera is a multi-stemmed plant that can reach a height of 4.48m and a diameter of 7.4cm in two years. It is recommended that C. procera seeds for raising nursery stock should be sourced from the nearest source possible. This will reduce the environmental and climatic effects associated with long distance seed transfers and ensure the species benefits from home-site advantages.

Freezing and Heating Tolerance of Pinus nigra Seedlings from Three South to North Balkan Provenances

To meet the restoration and reforestation goals in the changing environment, the translocation of genotypes and species northward and upward need to be considered to a great extent. Pinus nigra is a genetically diverse, drought sensitive species, with cold hardiness comparable to other tree species under the same climatic conditions. This study tested frost hardiness (whole plant freezing test—WPFT, and electric conductivity—EC test), and heat tolerance (heat tolerance test) of P. nigra seedlings from two southern Greek provenances (Kalamata and Grevena) and one northern Serbian provenance (Šargan) to better understand the potential of seed transfer from the south to the north of the species distribution in the Balkan peninsula. The results showed that, that for all studied provenances, the damage was great; the index of injury (Ii) at −18 °C was ranged from 49 to 54.5 (measured by the EC method) and the percentage of injured tissues ranged from 80–90% (measured by visual observation). For all studied provenances, a sharp increase in damages was observed with the fall of temperature from −5 and −18 °C and the time after exposure. The WPFT results showed that the highest tolerance to freezing (−18 °C) was presented by seedlings from the northern (Šargan) provenance; however, no significant differences were statistically detected among the studied provenances. The heat and drought-treated seedlings, from both provenances, presented significantly highler foliar damages than only drought-treated ones. For seedlings from both contrasting provenances (Grevena and Šargan), exposure to moderate heat (45 °C) and short drought did present damages but without significant difference between them. Considering freezing and heating tolerance, Greek provenances of P. nigra (i.e., Grevena region) can be successfully used in Serbian forestation and restoration programs. The present study makes a contribution towards P. nigra reforestation with practical implications for abiotic stress (frost, heat drought) tolerance among southern and northern provenances and could be valuable to determine the suitable provenances for reforestation programs and assisted population migration under climatic change scenarios.

Evolvability of Drought Response in Four Native and Non-native Conifers: Opportunities for Forest and Genetic Resource Management in Europe

Intraspecific genetic variation in drought response is expected to play an important role in determining the persistence of tree populations in global change as it (1) allows for spontaneous selection and local adaptation of tree populations, (2) supports assisted seed transfer of less-drought-sensitive provenance, and (3) enables the integration of drought-sensitivity traits into tree breeding. Estimating the potential of such adaptation options requires quantitative genetic knowledge of drought sensitivity across significant parts of species distributions and a comparative assessment of genetic variation within economically and ecologically important tree species. We quantified genetic variation within and among populations of four conifers growing within common garden experiments in the drought-prone eastern Austria. This region experienced three strong drought periods between 1980 and 2010 that resulted in significant reductions in radial growth. Among the four tested species, Douglas-fir revealed the highest resistance during drought and silver fir the best recovery after drought, while European larch and Norway spruce showed the lowest resistance. High genetic variation among populations and phenotypic stability across all three drought events was found for Norway spruce and silver fir, but not for the other species. Heritability and evolvability of drought traits, both approximated via genetic repeatability, revealed strong differences among populations of all four species. Repeatability and evolvability for resistance were highest in Norway spruce and, for recovery, highest in European larch. Our comparison indicates that the mean drought sensitivity of a species is not related to the intraspecific genetic variation in drought response. Thus, also highly drought-sensitive species, such as Norway spruce and European larch, harbor significant genetic variation in drought response within and among populations to justify targeted tree breeding, assisted gene flow, and supportive forest management to foster local adaptations to future conditions.

Sclerophthora rayssiae var. zeae (brown stripe downy mildew of maize).

The first record of brown stripe downy mildew of maize occurred in India in the early 1960s. In 1967, the pathogen was defined as Sclerophthora rayssiae var. zeae by Payak and Renfro. It spread rapidly across India, especially in regions with over 100 cm of annual rainfall and into neighbouring countries, probably via seed transfer. It has been effectively controlled by the use of resistant hybrids and seed treatment. It is not reported to be an invasive species.

Scots pine (Pinus sylvestris L.) reaction to climate change in the provenance tests in the north of the Russian plain

Species with continuous distribution area will be impacted by climate change in different ways. That is related to the population’s geographical position and climate features of the population formation. Short-term response of Scots pine (Pinus sylvestris L.) was studied with taken into consideration intraspecies features of populations. Provenance tests in the Arkhangelsk (62.60 N, 39.98 E) and Vologda (62.60 N, 39.98E) regions located in the north of the Russian Plain were used. Provenances collection (23 provenances from the northern, middle, and southern taiga subzones and mixed forest zone) from areas with different climate characteristics was considered. Clinal variability and a reaction norm of vegetative and generative response to various levels of temperature change and seed transfer were studied. Average actual height and diameter values for 31-year provenances and calculated values for provenances were compared using ‘latitudinal growth coefficient’ proposed by I.V. Volosevich (1984) for the north of the Russian Plain. Provenance reproductive ability response was assessed using seed-bearing trees’ numbers in provenances of the 1st class of age. Pine growing in the north of the Russian Plain would respond to warming by productivity increasing more significantly than pine growing in the south. Response of pine from the northern and middle taiga subzones on climate warming can be expected on 1.01 m and 1.12 cm to temperature rise by 100°C for height and diameter, and 0.85 m and 0.93 cm for seeds transfer to 1 degree of northern latitude to southward. Probable reaction norm for pine reproduction potential under temperature change by 100°C of the sum of the temperatures above 10ºС and seed transfer by 1 degree of northern latitude can be expected about 6%.

Sclerophthora rayssiae var. zeae (brown stripe downy mildew of maize).

The first record of brown stripe downy mildew of maize occurred in India in the early 1960s. In 1967, the pathogen was defined as Sclerophthora rayssiae var. zeae by Payak and Renfro. It spread rapidly across India, especially in regions with over 100 cm of annual rainfall and into neighbouring countries, probably via seed transfer. It has been effectively controlled by the use of resistant hybrids and seed treatment. It is not reported to be an invasive species.

Seeds of change? Seed transfer governance in British Columbia: insights from history

Tree seed transfer is critical to effective reforestation programs, and exploring its policy roots provides insights to understand future, and potentially controversial, actions like assisted migration. We offer a historical overview of seed transfer governance in British Columbia, Canada, by applying analytics from the policy change and knowledge co-production literatures. Based on document analysis and semi-structured interviews with key informants, we trace governance attributes to examine how and why policies have changed (or not) over time. We reveal a paradigmatic shift in seed transfer governance, culminating in a climate-based seed transfer system — informed largely by genetic knowledge — that emerged through a policy window opening. In contrast, governance processes remained relatively unchanged in practice, including the disproportionately influential role of the forest industry in policy-making. These insights shed light on the legacies of a government–industry policy coalition that influence underlying seed transfer objectives (i.e., forest productivity), and help to explain the ongoing dominance of particular knowledge forms used to inform policy. We highlight the need for increased contributions from a wider range of expertise, stakeholders, and rights holders in developing seed transfer policies for future forests.