Modelling Shifts and Contraction of Seed Zones in Two Mexican Pine Species by Using Molecular Markers

A seed zone or provenance region is an area within which plants can be moved with little risk of maladaptation because of the low environmental variation. Delineation of seed zones is of great importance for commercial plantations and reforestation and restoration programs. In this study, we used AFLP markers associated with environmental variation for locating and delimiting seed zones for two widespread and economically important Mexican pine species (Pinus arizonica Engelm. and P. durangensis Martínez), both based on recent climate conditions and under a predicted climate scenario for 2030 (Representative Concentration Pathway of ~4.5 Wm−2). We expected to observe: (i) associations between seed zones and local climate, soil and geographical factors, and (ii) a meaning latitudinal shift of seed zones, along with a contraction of species distributions for the period 1990–2030 in a northward direction. Some AFLP outliers were significantly associated with spring and winter precipitation, and with phosphorus concentration in the soil. According to the scenario for 2030, the estimated species and seed zone distributions will change both in size and position. Our modeling of seed zones could contribute to reducing the probabilities of maladaptation of future reforestations and plantations with the pine species studied.

ON THE POSSIBILITY OF APPLYING A NEW SET OF SINGLE-NUCLEIC POLYMORPHISMS LOCI TO THE OPTIMIZATION OF THE FOREST SEED AREA OF PEDUNCULATE OAK

We tested 95 new, geographically informative nuclear SNP loci of pedunculate oak in order to identify genetic differences of populations in the same seed zone. In a cluster analysis all individuals of the two studied stands are divided into two distinct groups. We observed statistically significant genetic differentiation of two populations (genetic distance d_0 = 0.170, parameter of differentiation 〖delta〗_T = 0.1696, genetic fixation F_ST = 0.0687) and higher genetic variability in the lowland stand (P = 91,58%, observed heterozygosity H_O = 0.364, expected heterozygosity H_E = 0.330, diversity of alleles υа = 1.58) in comparison to the oak stand in the Volga uplands (P = 77,89%, H_O = 0.327, H_E = 0.272, υа = 1.47). We concluded that these oak forests should be subdivided into different seed zones. Continuing the research by using the set of SNP loci and expanding the set of studied populations will supply Russian forestry by genetic information to optimize the forest seed zoning of the pedunculate oak.

Results of 20 years old Douglas-fir provenance experiment established on the northern slopes of Rila Mountain in Bulgaria

The purpose of this study is to facilitate the detection of provenances relevant to the reforestation practice in Bulgaria. Studies were carried out in a Douglas-fir provenance trial plantation established at an altitude of 800 m a.s.l. on the northern slopes of Rila Mountain. To establish the productivity, assess the stands and rank provenances biometric procedures, methods of descriptive statistics and ANOVA were used. The diameter at breast height, average height, dominant height, total growing stock volume, assortment timber structure and survival of trees were analyzed in the stands of 55 Douglas-fir provenances. The provenances were characterized in terms of productivity of forest stands at 20 years of age and their ability to produce high quality timber was evaluated. Provenances: Newhalem No. 4 (Seed zone 402), Darrington No. 7 (Seed zone 403), Parkdale No. 19 (Seed zone 661) and Idanha No. 29 (Seed zone 452) have been recommended. Among the recommended provenances are those with growing stock volume with branches from 296 to 354 m³·ha^–1, mean annual increment from 14.8 to 17.7 m³·ha^–1 and dominant heights of up to 17.9 m.  

The Research of Camellia Oleifera Seed Winnowing Peel Test

On the basis of analyzing the properties of the Camellia oleifera peel and seed, for the purpose of solving the problem of the separation of peel and seed, a device has been designed based on the aerodynamic principles. The single factor experiment has been carried out to research how the feeding angle, feeding height, fan inclination and fan height can influence the seperation. The result shows that the feeding angle has a significantly effect on the separation, the suitable angle is 40°; the feeding height has a significantly effect on the separation; when the feeding height is 200mm, the peel in the seed zone is the least, but the seed in mixing zone is the most, when the feeding height is 300mm, the seed in the mixing zone is the lesat, but the peel in the seed zone is the most, so in the actual production, the feeding height need to be comprehensive considered; the fan inclination has a significantly effect on the separation, the suitable inclination is 15°; the fan height does not have a significant effect on the separation.

Predicting seed dormancy loss and germination timing for Bromus tectorum in a semi-arid environment using hydrothermal time models

A principal goal of seed germination modelling for wild species is to predict germination timing under fluctuating field conditions. We coupled our previously developed hydrothermal time, thermal and hydrothermal afterripening time, and hydration–dehydration models for dormancy loss and germination with field seed zone temperature and water potential measurements from early summer through autumn to develop predictions of germination timing for Bromus tectorum at a semi-arid site in north-central Utah, USA. Model predictions were tested with a validation dataset based on concomitant seed retrieval experiments in 2 years. Predictions were generally in agreement with observed field germination time courses, even though integration across multiple precipitation events was necessary. Success of the modelling effort hinged on two factors. First, we used a soil capacitance sensor that measured seed zone (5 mm soil depth) water content accurately over a wide range. Second, simulations were built using physiologically based threshold models that can incorporate differences in germination timing for multiple germination fractions and for multiple stages of dormancy loss. Our results suggest that simulation models using hydrothermal time concepts can predict field germination phenology accurately. Seeds in this study integrated their experiences in a widely fluctuating environment in a manner consistent with the assumptions of hydrothermal time. Such threshold-based models also have the advantage of generality, as these concepts can be applied to many different species, environments and weather scenarios.

Genetic Variation in Frost Damage and Seed Zone Delineation within an Altitudinal Transect of Pinus devoniana (P. michoacana) in Mexico

We explored the patterning of genetic variation among Pinus devoniana Lindl. (also known as P. michoacana Martínez) populations to develop guidelines for seed and seedling movements, intended for improving the matching between genotypes and environments regarding frost tolerance, in reforestation programs. Open-pollinated seed from 16 populations along an altitudinal transect (1600 to 2450 m) were collected near Morelia, State of Michoacán, México. A common-garden provenance test, established with 2.5-year-old seedlings, was assessed for frost resistance conducting a laboratory frost damage test (-9°C). Results indicate that there were significant differences among provenances (P = 0.0261) for frost damage. Variation among provenances was structured as an altitudinal cline, with populations from lower altitudes being the least tolerant to frost. Linear regression statistics suggest that for each increment of 100 m of provenance altitude, there will be a 5.2% decrease in frost damage. We suggest the use of two provisional altitudinal seed zones of 400 m breadth each (lower and upper limits for zone 1: 1600 m and 2000 m of altitude; for zone 2: 2000 and 2400 m, respectively), and for reforestation of a given site, the use of seedlings originated from seed of the same seed zone or within ±200 m of altitude from the elevation of the reforestation site.