Genetic Diversity and Genome-Wide Association Study for Growth and Wood Quality Traits in E. camaldulensis.

VILLALBA, PAMELA V.; AGUIRRE, NATALIA C.; GARCIA, MARTÍN N.; ACUÑA, CINTIA V.; RIVAS, JUAN G.; MARTINEZ, M. CAROLINA; LUDUEÑA, A.; DIAZ, M.; PATHAUER, PABLO S.; CAPPA, EDUARDO P.; ALVES, A.; RODRIGUEZ, JOSÉ C.; GRATTAPAGLIA, DARIO; HOPP, ESTEBAN H.; CARRERAS, ROCÍO; CISNEROS, ESTEBAN F.; MARCUCCI POLTRI, SUSANA N.

Harbin

Conferencia; The 20th IUFRO Tree Biotech and the 2nd FTMB (Forest Tree Molecular Biology and Biotechnology) Conference; 2022

Knowing and maintaining genetic diversity in tree breeding programs is crucial in the context of climate change and for molecular breeding approaches such as a Genome-Wide Association Study (GWAS). This work assessed the genetic variation of a Eucalyptus camaldulensis Dehnh population and the detection of new marker-trait associations (MTA) for eight growth and wood quality traits.To achieve these goals, 689 individuals were chosen from a progeny trial (implanted in 1996 by The National University of Santiago del Estero, UNSE), consisting of 2,200 trees (between 1 and 12 individuals per family) from 110 open-pollinated families of 14 different provenances. These selected trees were phenotyped by NIR analysis of wood and conventional measurements of growth, and genotyped by EUChip60K chip, resulting in 19,034 polymorphic SNPs.The genetic diversity values were consistent with those expected for the species (Polymorphic Information Content, PIC = 0.27; Observed Heterozygosis, Ho = 0.35; Expected Heterozygosis, He = 0.34). An analysis of the population structure showed six subgroups and low differentiation among them (FST = 0.062). GWAS for growth traits identified two MTAs for diameter at breast height (explaining 2 and 2.3% of the variance at five and 12 years, respectively) and one for wood density (2.1% of variance). For wood quality traits GWAS showed one MTA for total and ethanolic extractives (3 and 2.8% of the variance, respectively), one for cellulose (3% of variance), one for syringyl:guaiacyl ratio (3.1% of variance), and three shared between total and Klason lignin (9.1% of the variance for each trait). Sequences of the markers with significant associations were mapped and annotated using the E. grandis genome. Potentially interesting genes were identified in silico nearest the MTA regions.The findings of these studies provide valuable information regarding genetic diversity and useful marker-trait associations for genetic improvement in this population.