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Abstract
A source of resistance to widespread and severe mosaic caused by cucumber mosaic virus (CMV) on late summer-grown lettuce in New York State was found in plant introduction (PI) 261653, an accession of Lactuca saligna L. from Portugal. Resistance to CMV was dominant in F1 plants of L. saligna × L. sativa L. However, this resistance was proved to be viral strain specific, necessitating the search for an additional source for the control of a newly recognized strain of CMV able to infect PI 261653 systemically.
Abstract
A 6-year (1975-1980) survey established that broad bean wilt virus (BBWV) was second only to cucumber mosaic virus (CMV) in causing destructive diseases in leading lettuce cultivars grown in New York State. Conversely, the widespread usage of certified seed had drastically reduced the occurrence of lettuce mosaic virus (LMV). Screening for resistance revealed that a number of accessions of Lactuca sativa and a few of L. virosa were tolerant to BBWV. Tolerant plants, although infected with the virus, remained symptomless or responded with a mild and often transient chlorotic mottle.
Abstract
In greenhouse tests, domestic and foreign accessions of Cichorium endivia L. were susceptible to turnip mosaic virus (TuMV), the most common and often destructive virus occurring in late plantings of endive and escarole in the Northeast United States, whereas those of chicory (C. intybus L.) and C. pumilum Jacq. were resistant. Thus, chicory represents a valuable source of TuMV resistance for interspecific gene transfer to endive and escarole. Resistance was dominant in F1 plants of C. intybus × C. endivia.
Abstract
No significant resistance to verticillium wilt (Verticillium dahliae Kleb) was found in 59 eggplant (Solanum melongena L.) accessions, in a sexual hybrid between S. melongena and S. integrifolium, or in eight somatic hybrid clones between S. melongena and S. sisymbriifolium. A relatively high degree of resistance was observed in accessions of S. aculeatissimum, S. scabrum, and S. sisymbriifolium. All 58 accessions of S. gilo tested were susceptible, as were all accessions of S. incanum, S. integrifolium, S. laciniatum, S. macrocarpum, S. mammosum, and S. nodiflorum.