Key triggers of adaptive genetic variability of sessile oak [Q. petraea (Matt.) Liebl.] from the Balkan refugia: outlier detection and association of SNP loci from ddRAD-seq data.

Knowledge on the genetic composition of Quercus petraea in south-eastern Europe is limited despite the species' significant role in the re-colonisation of Europe during the Holocene, and the diverse climate and physical geography of the region. Therefore, it is imperative to conduct research on adaptation in sessile oak to better understand its ecological significance in the region. While large sets of SNPs have been developed for the species, there is a continued need for smaller sets of SNPs that are highly informative about the possible adaptation to this varied landscape. By using double digest restriction site associated DNA sequencing data from our previous study, we mapped RAD-seq loci to the Quercus robur reference genome and identified a set of SNPs putatively related to drought stress-response. A total of 179 individuals from eighteen natural populations at sites covering heterogeneous climatic conditions in the southeastern natural distribution range of Q. petraea were genotyped. The detected highly polymorphic variant sites revealed three genetic clusters with a generally low level of genetic differentiation and balanced diversity among them but showed a north-southeast gradient. Selection tests showed nine outlier SNPs positioned in different functional regions. Genotype-environment association analysis of these markers yielded a total of 53 significant associations, explaining 2.4-16.6% of the total genetic variation. Our work exemplifies that adaptation to drought may be under natural selection in the examined Q. petraea populations.

The Effect of Tree Spacing on Yields of Alley Cropping Systems-A Case Study from Hungary.

Alley cropping is a specific agroforestry system, which is regarded as sustainable land use management, that could play a crucial role in climate change adaptation and mitigation. Despite its appealing attributes, farmers' up-take of the system is slow in temperate regions. This study aims to contribute to scaling-up agroforestry through a case study in Hungary and to help to design productive alley cropping systems. We investigated which tree planting pattern of black locust (Robinia pseudoacacia L.) results in the most productive alley cropping system when intercropped with triticale (x Triticosecale W.) by statistically analysing the yields of the intercrop and of the trees in nine different layouts and by calculating land equivalent ratios (LER). There was significant difference between the treatments both in triticale and black locust yields. The more trees planted on a hectare, the higher the volume of the stand, and the less yield of triticale was observed, although the latter correlation was weak and in some cases the triticale was more productive between the trees compared with sole crop control. Eight out of nine treatments had favourable LER (0.94-1.35) when the trees were five years old. Black locust and triticale seem to be a good combination for productive alley cropping systems.

Allelic variation in candidate genes associated with wood properties of cultivated poplars (Populus).

INTRODUCTION: Since Populus has veritable value as timber, plywood, pulp, and paper, genomic research should create the sound basis for further breeding toward desirable wood quality attributes. MATERIALS AND METHODS: In this study, we addressed the need for a research methodology that initially identifies and then characterize candidate genes encoding enzymes with wood property phenotypic traits, toward the aim of developing a genomics-based breeding technology. RESULTS: On 23 different poplar species/hybrid samples, we successfully amplified 55 primers designed on Populus trichocarpa L. Considering the number of polymorphic sites, out of 73,206 bp, 51 SNPs and 31 indel events were found. Non-synonymous single base mutations could be detected in number of 30, 21 out of 164 sequences were the number of minimum recombination events and 41 significant pairwise comparisons between loci could be detected. DISCUSSION AND CONCLUSION: Our results provide a roadmap for a future association genetic study between nucleotide diversity and precise evaluation of phenotype.