Factors contributing to the utility as food of five grades of Michigan potatoes

American Journal of Potato Research -     

Dissection of genomic correlation matrices of US Holsteins using multivariate factor analysis

The aim of this study was to compare correlation matrices between direct genomic predictions for 31 traits at the genomic and chromosomal levels in US Holstein bulls. Multivariate factor analysis carried out at the genome level identified seven factors associated with conformation, longevity, yield, feet and legs, fat and protein content traits. Some differences were found at the chromosome level; variations in covariance structure on BTA 6, 14, 18 and 20 were interpreted as evidence of segregating QTL for different groups of traits. For example, milk yield and composition tended to join in a single factor on BTA 14, which is known to harbour the DGAT1 locus that affects these traits. Another example was on BTA 18, where a factor strongly correlated with sire calving ease and conformation traits was identified. It is known that in US Holstein, there is a segregating QTL on BTA18 influencing these traits. Moreover, a possible candidate gene for daughter pregnancy rate was suggested for BTA28. The methodology proposed in this study could be used to identify individual chromosomes, which have covariance structures that differ from the overall (whole genome) covariance structure. Such differences can be difficult to detect when a large number of traits are evaluated, and covariances may be affected by QTL that do not have large allele substitution effects.     

Tall planting stock for enhanced growth and domination of brush in the Douglas-fir region

Two long-term experiments followed development of planted stock of various sizes, origins, and species. In one experiment, multiyear comparisons of container, 2-0 bareroot, and 3-year-old Douglas-fir transplants showed strong positive relationship between initial height and long-term (10–14 years) growth under a range of site conditions with high probability of brush development. In the other experiment, Douglas-fir, western hemlock, and Sitka spruce were planted in salmonberry disturbed by logging 0 and 4 years previously. Half the seedlings were released with glyphosate 6 months after planting. Hemlock and Douglas-fir bare-roots all grew well if planted in a fresh burn, despite rapid regrowth of salmonberry, but virtually all seedlings less than 60 cm tall except Sitka spruce were killed by 4-year-old salmonberry if not released. Release improved growth of seedlings in the fresh burn by 6%, gaining an average of about 0.6 year toward reaching a height of 6 m. Release improved growth of survivors in 4-year-old salmonberry by 51% in height, 72% in diameter, and 325% in volume at age 12. Sitka spruce grew well until damaged by insects. Hemlock growth was equal to or greater than that of Douglas-fir of comparable initial height. In all comparisons, the probability of being overtopped by brush decreased with increasing initial stock height, and the effect of suppression on growth was also inversely related to initial height. Field planting operations may require special logistic measures for the largest stock types.This is Paper 2706 of the Forest Research Laboratory, Oregon State University.