Improvement of potato protein II. Selection for protein and yield

The improvement of potato protein appears feasible by selecting high protein parents and crossing them with adapted Group Tuberosum parents. Initial hybrids were obtained with about 10% protein which is double that of Red Pontiac. This protein is of high nutritional value when compared to whole egg protein. Some of the hybrids appear to have yields approaching standard varieties. Specific gravity values are also comparable.     

Finite element method evaluation: articulations and diagonals in an 8-pin type 1B external skeletal fixator

OBJECTIVE: To determine the mechanical properties of articulations and diagonals in an 8-pin type 1b external skeletal fixator (ESF). STUDY DESIGN: Finite element method-computer simulation. METHODS: The control type 1b ESF was supplemented with different articulations and diagonals. The parameters of frame angle, articulation diameter, and pin- or connector-based fastening were altered. The configurations were loaded for axial compression, torsion, and craniocaudal and mediolateral bending as single loads and as a combination. Three-dimensional linear and rotational gap strain and Von Mises stress maxima were determined. RESULTS: For 90 degrees , 60 degrees , and 30 degrees frame angles and 0.48-cm-diameter articulations and diagonals, the best configurations, based on lower gap strain combined with decreased or minimally increased stress maxima for the combined load, were single or double diagonals or four horizontal articulations. Combining double diagonals with double wide horizontal articulations further lowered gap strain. For a 90 degrees frame angle and 0.32-cm-diameter articulations and diagonals, the superior configurations, showing the lowest gap strain combined with decreased or minimally increased stress maxima for the combined load, were double diagonals, four horizontal, or wide double horizontal articulations. The 0.48-cm articulations and diagonals provided lower or similar gap strain than 0.32-cm articulations and diagonals. The connector-to-connector version of these superior configurations provided slightly lower or similar gap strain and stress maxima than the pin-to-pin version. Only pin-to-pin-fastened double diagonals provided better stress maxima than the corresponding connector-to-connector version. CONCLUSIONS: Supplementing a type 1b ESF with double diagonals and wide double articulations results in the greatest increase in stability at the fracture gap for complex fractures or in the initial phase of bone healing.     

Räumliche Variabilität von Stoffkonzentrationen am Grundwasserspiegel bei einem grundwasserfernen Sandstandort unter Kiefern

Spatial variability of groundwater solute concentrations at the water table under a pine stand on sandy soil with deep groundwater Aim of the study was to prove the evidence of a direct influence of solute input pattern (induced by canopy throughfall) on the pattern of groundwater solute concentration at the water table even at sites with groundwater table of 4–5 m below surface. The test site was a weakly buffered sandy soil with groundwater table ca. 4.3 m below surface (Podzol soil with some features of former gley process) under a cultivated pine stand (age ca. 60 years). Groundwater at the water table was sampled in between two rows of trees along a 30 m transect at 0.5 m intervals. As example, the results for sulfate concentration (the key solute of soil and groundwater acidification) show rather high variation along the transect. But a thorough stochastic analysis of empirical data sets reveals cyclic oszillations occurring synchronous and with same period length for sulfate concentration at the water table and for canopy coverage of the ground (and therefore for solute input). An additional long-periodic oscillation is strongly superimposing in the case of sulfate concentration. Thus the results indicate a direct influence of the pattern of canopy throughfall on the pattern of sulfate concentration at the water table. However, this influence is rather weakly pronounced at this deep groundwater site compared to corresponding shallow groundwater sites.     

Relative resistance of the potato cultivar krantz to common scab caused byStreptomyces scabies as determined by cluster analysis

Twenty potato breeding selections and five potato cultivars (25 clones) were evaluated in replicated field plots for their resistance to common scab caused byStreptomyces scabies, at Presque Isle, ME and Cranesville, WV in 1993. At harvest, all tubers in each plot were individually scored for the surface area covered (0=0% to 5>75%) and for lesion type (0=no lesions to 5=pitted lesions). The individual tuber scores for either surface area covered or lesion type for each plot were totaled and divided by five times the number of tubers to create an index of surface area covered (SAI) or lesion type (LI), respectively. Clonal mean SAI ranged from 0.05 to 0.96 in Maine and 0.21 to 0.89 in West Virginia. Clonal mean LI ranged from 0.06 to 1.0 in Maine and 0.48 to 1.0 in West Virginia. There were significant differences among clones for SAI and LI. Clones were clustered on mean SAI and LI in ME and WV. The clones clustered into four groups. The resistance of Krantz and two breeding selections, B0348-2 and B0339-1, was similar to Ontario.     

Response of Nooksack potatoes to nitrogen fertilizer

The Nooksack cultivar because of differing characteristics may have different responses to grower management practices developed principally for Russet Burbank. This study was conducted to determine the effects of nitrogen on yield, grade, and specific gravity of the Nooksack cultivar. In irrigated field experiments, N fertilizer was sprinkler-applied daily on Quincy sand soil. In other experiments, on a Warden silt loam soil all N was broadcast and incorporated before planting. Fertilization rate did not significantly affect tuber grade or specific gravity. Short term shifts in N supply did not cause tuber deformities and poor grades as they commonly do with Russet Burbank. Nooksack, while responsive, did not have a strong positive response to N fertilization. Tuber yields were depressed at fertilizer plus residual N levels above 200 kg/ha on Warden silt loam and above 300 kg/ha on Quincy sand. This difference was because of variation in NO₃ leaching and soil N mineralization and was reflected in calculation of optimum N rates. Nooksack may require less N fertilization than Russet Burbank partially because of the strong dormancy of Nooksack tubers that retards emergence and shortens growing season. Management to promote more rapid dormancy break and lower N nutrition during tuber initiation could result in earlier establishment, earlier tuber bulking, and greater yields of Nooksacks.