Depth to basement and thickness of unconsolidated sediments for the western United States—Initial estimates for layers of the U.S. Geological Survey National Crustal Model

abstract To determine a crustal model for the southwest side of the San Andreas fault, six large quarry blasts near Salinas, California, were recorded at 27 seismographic stations in the region around Salinas, and along a line northwest of the quarry toward San Francisco. Data from these explosions are compared with results of explosion-seismic studies carried out by the U.S. Geological Survey on a profile along the coast of California from San Francisco to Camp Roberts. The velocity of Pg, the P wave refracted through the crystalline crust, in the Salinas region is 6.2 km/sec and the velocity of Pn is about 8.0 km/sec. Velocities of the direct P wave in near-sur-face rocks vary from one place to another, and appear to correlate well with gross geologic features. The thickness of the crust in the region southwest of the San Andreas fault from Salinas to San Francisco is about 22 kilometers.

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Identification of Resistance to Powdery Mildew in Publicly Available Male Hop Germplasm

Plant Health Progress ◽

10.1094/php-05-18-0027-rs ◽

2018 ◽

Vol 19 (3) ◽

pp. 258-264

Author(s):

David H. Gent ◽

Briana J. Claassen ◽

Megan C. Twomey ◽

Sierra N. Wolfenbarger

Keyword(s):

United States ◽

Powdery Mildew ◽

Pacific Northwest ◽

Western United States ◽

R Genes ◽

Sources Of Resistance ◽

Department Of Agriculture ◽

Breeding Programs ◽

The Pacific ◽

The U.S

Powdery mildew (caused by Podosphaera macularis) is one of the most important diseases of hop in the western United States. Strains of the fungus virulent on cultivars possessing the resistance factor termed R6 and the cultivar Cascade have become widespread in the Pacific Northwestern United States, the primary hop producing region in the country, rendering most cultivars grown susceptible to the disease at some level. In an effort to identify potential sources of resistance in extant germplasm, 136 male accessions of hop contained in the U.S. Department of Agriculture collection were screened under controlled conditions. Iterative inoculations with three isolates of P. macularis with varying race identified 23 (16.9%) accessions with apparent resistance to all known races of the pathogen present in the Pacific Northwest. Of the 23 accessions, 12 were resistant when inoculated with three additional isolates obtained from Europe that possess novel virulences. The nature of resistance in these individuals is unclear but does not appear to be based on known R genes. Identification of possible novel sources of resistance to powdery mildew will be useful to hop breeding programs in the western United States and elsewhere.

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