VIRUS Y, vein banding or vein clearing, (X + Y = rugose mosaic). O. S. R.: Hypersensitivity in Solanum simplicifolium, S. salamanii, S. demissum, S. rybinii, and accession Nos. 25941 and 25942. Immunity in S. chacoense, S. cordobense, S. garciae, S. macolae, S. ajuscoense, S. antipovichi, S. polyadenium, and probably S. commersonii and S. chaucha. Field immunity in accession Nos. 25830 and 25832. Weak resistance in Katandin and Chippewa. P. S. R.: In original sources and in seedling varieties related to them. Inheritance: Tetrasomic. Hypersensitive reaction depends on one or more recessive genes. Tolerance to virus is dominant.

YELLOW DWARF. O. S. R.: Sebago, Russet Burbank, and Irish Cobbler are resistant but not immune. P. S. R.: Sebago, Russet Burbank, Irish Cobbler. Inheritance: Unknown.

SPINACH BLUE MOLD, Peronospora effusa. O. S. R.: United States Department of Agriculture collection, P. E. I. 140467, made in Iran in 1940. P. S. R.: Commercial types are now being developed. Inheritance: Resistance is a monogenic dominant.

FUSARIUM WILT, Fusarium oxysporum spinaciae. O. S. R.: Commercial Virginia Savoy. P. S. R.: Resistant selection of Virginia Savoy was developed by the Virginia Truck Experiment Station. Inheritance: Not determined.

BLIGHT, cucumber virus 1. O. S. R.: Wilt plant of Spinacia oleracea, collected near Liaoyang in North Manchuria in 1918. P. S. R.: Commercial varieties Virginia Savoy and Old Dominion. Inheritance: Resistance is monogenic dominant.

SWEETPOTATO STEM ROT (WILT), Fusarium hyperoxysporum and F. oxysporum f. batatas. O. S. R.: Selections from open-pollinated seedlings of Cuban variety Americano; P. E. I. 153655, introduced from Tinian Island in 1946; Triumph, a white-flesh American variety; and Japanese white-flesh varieties Norin No. 2, Norin No. 3, Taihaku Saitama No. I. P. S. R.: Goldrush and numerous seedling selections now being developed. Inheritance: Multiple factor.

TOMATO BACTERIAL CANKER, Corynebacterillm michiganense. O. S. R.: Some collections of Lycopersicon pimpinellifolium. P. S. R.: L. pimpinellifolium. No commercial varieties. Inheritance: Unknown.

BACTERIAL WILT, Pseudomonas solanacearum. P. S. R.: Puerto Rico pear and some L. pimpinellifolium. P. S. R.: Preceding varieties and commercial types now being developed. Inheritance: Unknown.

COLLAR ROT, Alternaria solani. O. S. R.: Devon Surprize and some other European forcing varieties. P. S. R.: Southland, Urbana, and other commercial types under development. Inheritance: Monogenic; fluctuating dominance.

EARLY BLIGHT, Alternaria solani. O. S. R.: Devon Surprize and some other European forcing varieties. P. S. R.: Preceding varieties and commercial types now being developed. Inheritance: Probably two factors or more.

FUSARIUM WILT, Fusarium bulbigenum var. lycopersici. O. S. R.: P. E. 1. 79532 from Peru and other collections of L. pimpinellifolium. P. S. R.: Pan America, Sunray, Southland, Fortune, Jefferson, Golden Sphere, and Manahill. Inheritance: Monogenic; near-immunity partially dominant.

GRAY LEAF SPOT, Stemphylium solani.

O. S. R.: L. pimpinellifolium. ' P. S. R.: L. pimpinellifolium and commercial types now being developed. Inheritance: Monogenic; resistance dominant, linked with wilt immunity.

LATE BLIGHT, Phytophthora infestans.

O. S. R.: Low-level resistance in several wilt types of L. esculentum, i. e., P. E. I. 134208 from India. P. S. R.: Low-level resistance in Garden State and Southland. Inheritance: Two small-fruited tomato types used as ornamentals and designated as P, and P3 were observed to have a high degree of resistance in southern Florida. Inheritance segregation ratios in crosses made with cultivated varieties indicated that resistance was due to one main factor and one or more modifying factors. F3 stocks uniformly resistant at Homestead, Fla., were not resistant in the high valleys of North Carolina or at Huttonsville, W. Va. The reason for the difference has not been determined.

LEAF MOLD, Cladosporium fulmm.

O. S. R.: L. pimpinellifolium and L. hirsutum. P. S. R.: Vetomold, Improved Bay State, Quebec 5, and Globelle. Inheritance: Polygenic dominance incomplete. Multiple strains of causative organism.

SEPTORIA LEAF SPOT, Septoria lycopersici. O. S. R.: L. hirsutum, P. E. I. 127827 from Peru, and T6 02 M6.

P. S. R.: Preceding varieties and commercial types now being developed. Inheritance: Resistance partially dominant.

VERTICILLIUM WILT, Verticillium alboatrum. O. S. R.: Peru wilt, L. pimpinellifolium, and Utah accession No. 665. P. S. R.: Riverside, Essar, Simi, VR 4, and VR 11. Inheritance: Resistance is monogenic dominant.

CURLY TOP, Ruga verrucosans. O. S. R.: L. peruvianum var. dentatum; P. E. 1. 128660, collected in Tacna, Peru, 1938; L. chilense; L. pissisi; P. E. I. 127829, collected between San Juan and Magdalena, Peru, 1938; L. glandulosum; P. E. I. i26440, collected between Yangos and Canta, Peru, 1938; and Red Peach. P. S. R.: Original introductions and commercial types now being developed. Inheritance: Not determined.

MOSAIC, Marmon tabaci. O. S. R.: L. hirsutum. P. S. R.: L. hirsutum; no commercial varieties. Inheritance: Unknown.

ROOT KNOT, Meloidogyne incognita.

O. S. R.: L. peruvianum. P. S. R.: L. peruvianum and commercial types being developed. Inheritance: Resistance partially dominant, apparently due to one or two major dominant genes; modifiers or additive action genes possible.

SPOTTED WILT, 3 viruses. O. S. R.: L. pimpinellifolium, L. peruvianum, and California BC 10. P. S. R.: Pearl Harbor, Manzana, German Sugar, Oahu, Lanai, Hawaii, Maui, Molokai, Kaudi, and Nuhau. The last 7 of these varieties probably inherited their resistance from German Sugar and L. peruvianum. anum. Inheritance: Resistance from Pearl Harbor to Hawaii strain of spotted wilt is a monogenic dominant.

WATERMELON ANTHRACNOSE, Colletotrichum lagenarium. O. S. R.: Native African melons:

P. S. R.: Congo. Inheritance: Monogenic, partially dominant.

DOWNY MILDEW, Pseudoperonospora cubensis. O. S. R.: Santo Domingo melons. P. S. R.: None. Inheritance: Unknown.

WILT, Fusarium niveum. O. S. R.: Probably citron P. S. R.: Hawkesbury, Leesburg, Blacklee, Klondike R7, etc. Inheritance: Unknown; probably polygenic.

FREDERICK J. STEVENSON has been employed since 1930 as a geneticist in charge of the national potato-breeding program of the Department of Agriculture. From 1919 to 1925, at the State College of Washington, he worked with breeding for resistance to bunt in wheat and smut in oats. From 1925 to 1930, at the University of Minnesota, he cooperated with others in breeding for resistance to rusts in wheat and oats and Helminthosporium in barley.

HENRY A. JONES has been with the Department of Agriculture since 1936. Previously he was head of the division of truck crops at the University of California. His chief investigations have had to do with the development of hybrid onions and disease resistance in onions. He is a graduate of the University of Nebraska and the University of Chicago, and in 1952 received an honorary degree of doctor of science from the University of Nebraska.

Rhizoctonia leaf spot on cotton.