Phenotypic and genetic characterization of Kyrgyz fine-leaved Festuca valesiaca germplasm for use in semi-arid,low-maintenance turf applications

Fine-leaved Festuca valesiaca Schleich. ex Gaudin (2n = 2x–4x) is native to heavily-grazed, cold, semi-arid, Asian rangelands. However, its potential for low-maintenance turf applications in the semi-arid western United States and its relatedness to other agriculturally important Festuca species have not been investigated. Therefore, a project was designed to identify F. valesiaca accessions that possess horticultural potential when grown under semi-arid growing conditions and to characterize their relatedness to other Festuca species. In 2008, 12 F. valesiaca accessions originating from Kyrgyzstan and eight US. Festuca and one Lolium cultivar were transplanted as replicated, spaced plants to a field nursery at Blue Creek, Utah. Relative vigor, height, width, total biomass (aboveground dry matter yield), seed weight, and seed number were evaluated between 2009 and 2011. Plant height, width, and total biomass of the F. valesiaca accessions examined were approximately equal to the commercial control, ‘Cascade’ (F. rubra L. subsp. commutata Gaudin; 6x; chewings fescue). Plant vigor and seed weight of F. valesiaca accessions PI 659923, PI 659932, W6 30575, and W6 30588 under semi-arid conditions (~300 mm annual precipitation) were significantly (P < 0.05) greater than ‘Cascade’. Moreover, principal component analysis based on all traits as loading factors indicated that these 12 F. valesiaca accessions were distinct from a majority of the other Festuca accessions examined. These F. valesiaca accessions produced abundant amounts of small seed, and this seed yield was significantly correlated with total aboveground biomass (dry weight; r ²  = 0.84, P < 0.001), plant height (r ²  = 0.58, P < 0.05), and plant vigor (r ²  = 0.83, P < 0.001). Amplified fragment length polymorphism (AFLP) analysis (1,454 polymorphic bands) was used to characterize F. valesiaca relatedness to other economically important Festuca species. The AFLP-based, neighbor-joining analysis differentiated F. valesiaca accessions from US Festuca cultivars examined, except for ‘Durar’ (F. ovina L.; 6x; sheep fescue), to which they had strong genetic affinities. Given their morphological attributes, F. valesiaca PI 659923, W6 30575, PI 659932, and W6 30588 should be considered for use in low-maintenance, semi-arid turf improvement programs in the western US.     

Molecular mechanics of cardiac myosin-binding protein C in native thick filaments

The heart's pumping capacity results from highly regulated interactions of actomyosin molecular motors. Mutations in the gene for a potential regulator of these motors, cardiac myosin-binding protein C (cMyBP-C), cause hypertrophic cardiomyopathy. However, cMyBP-C's ability to modulate cardiac contractility is not well understood. Using single-particle fluorescence imaging techniques, transgenic protein expression, proteomics, and modeling, we found that cMyBP-C slowed actomyosin motion generation in native cardiac thick filaments. This mechanical effect was localized to where cMyBP-C resides within the thick filament (i.e., the C-zones) and was modulated by phosphorylation and site-specific proteolytic degradation. These results provide molecular insight into why cMyBP-C should be considered a member of a tripartite complex with actin and myosin that allows fine tuning of cardiac muscle contraction.     

Spread of white hypovirulent strains of Cryphonectria parasitica on grafted American chestnut trees exhibiting a high level of blight control

In 1982 and 1983, natural blight cankers, located in a zone extending from the ground to 183 cm on the main stem of grafted American chestnut trees, were inoculated with a mixture of dsRNA-containing, white (European) and pigmented hypovirulent strains of Cryphonectria parasitica (H-inoculated zone). In 1996, white isolates (34% of 156 C. parasitica isolates) were recovered from superficial cankers throughout the grafts and as far as 564 cm from the H-inoculated zone. Lloyd's index of patchiness value (1.36) indicated that white isolates were slightly aggregated in cankers on the grafts. Forty-five percent of 95 C. parasitica isolates, recovered 5–50 months after inoculating the grafts with pigmented virulent strain WK, were white and some converted strain WK to the white phenotype in vitro. All cankers and bark cores yielding only pigmented isolates, vegetatively compatible with virulent strain WK, had superficial necrosis 5 and 11 months after inoculation with strain WK. All white isolates of C. parasitica assayed contained a 12.7 kbp dsRNA in high concentrations, and were hypovirulent in pathogenicity trials. Twenty-eight vegetative compatibility groups were identified among 65 pigmented graft area isolates; none of 48 pigmented isolates contained dsRNA. In addition to host resistance factors, spread of white strains may be responsible for the unusually high level of blight control on the grafts.     

Joint longitudinal modeling of age of dam and age of animal for growth traits in beef cattle

Two methods to jointly model age of dam (AOD) and age of animal in random regression analyses of growth in Gelbvieh cattle were examined. The first method (M1) was analogous to the multiple-trait analysis and consisted of AOD as a nested class variable and a cubic polynomial regression on age nested within birth, weaning, and yearly weights. The second method (M2) used two-dimensional splines, with age knots at 150, 205, 270, 340, and 390 d. The AOD knots were placed at 725, 1,464, and 2,189 d. These selected knots were used to form a two-dimensional grid containing 15 knots, each representing a specific age and AOD combination. A data set containing Gelbvieh growth records was split along contemporary groups into two data sets. Data set 1 contained 316,078 records and was used for prediction by mixed-model equations. Data set 2 contained 164,167 records and was used for cross validation. In the complete data set, only 90 and 30% of animals with birth weight had records on weaning and yearling weights, respectively. Models were evaluated based on R2, average squared error (ASE), percent bias, and plots of solutions. The ASE for weights associated with birth weight, weaning weight, and yearling weight for M1 were 15, 505, and 703 kg2. With M2, large jumps in fixed-effect estimates were observed outside the two-dimensional grid. To eliminate this problem, weighted one-dimensional splines were used for extrapolation beyond the two-dimensional grid. For M2 with weighted spline extrapolation, the ASE were 15, 542, and 777 kg2 for birth weight, weaning weight, and yearling weight, respectively. Creation of optimal two-dimensional splines is difficult when data are clustered. Despite such difficulties, the two-dimensional spline was capable of jointly and continuously modeling AOD and age of animal.     

Sulfur retention at intensively studied sites in the U.S. and Canada

We compiled and summarized current literature on S input/output budgets for intensively studied sites and soil plots in the U.S. and Canada and found S retention to be related to both soil order and extent of the last glaciation (Wisconsinan). Zero net retention is associated with Spodosols and was found only at sites north of the limit of Wisconsinan glaciation. Sites south of the limit of glaciation appear to be retaining from 20 to 90% of incoming S. These findings support the hypothesis that there exist regional variations in S retention in North America. Such variations are important in determining and predicting effects of acidic deposition on surface water chemistry.     

Regional patterns of sulfur retention in watersheds of the Eastern US

Retention of S was estimated in watersheds of the Eastern US by calculating S input-output budgets for 678 lake and reservoir watershed systems in the Northeast (NE), 98 lake and reservoir and 61 stream systems of the Southern Blue Ridge Province (SBRP) and 56 stream systems of Shenandoah National Park (SNP). Budgets were determined based on estimates of deposition and output (as surface water) for each of the sites. A variety of estimates of total S deposition were used. Percent S retention is high for sites in the SBRP and SNP but is distributed around zero for sites in the NE. These findings lend support to the hypothesis that patterns exist in S retention relative to the extent of the Late Wisconsinan glaciation.