Browsing by Author "MARHOLZ, G"

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    EFFECT OF POTATO VIRUS-Y ON GROWTH, YIELD, AND CHEMICAL-COMPOSITION OF FLUE-CURED TOBACCO IN CHILE
    (1984) LATORRE, BA; FLORES, V; MARHOLZ, G
    The effect of potato virus Y (PVY) on growth, yield and chemical composition of flue-cured tobacco cultivars Coker 86 and NC-744 was primarily determined by the time of inoculation. On Coker 86, early inoculations (15 and 28 days after transplanting) caused height reductions of 37.0 and 34.7% and yield reductions of 71.5 and 74.8%, respectively. Effects were less detrimental on NC-744, suggesting this cultivar possesses a degree of tolerance to the Chilean necrotic strain of PVY. Nevertheless, plant height and dry weight were reduced 9.9 and 16.3% and 36.9 and 38.9%, respectively, by inoculations 15 and 28 days after transplanting. PVY also modified the chemical composition of cured leaves. Total nicotine content was always higher in cured leaves from diseased plants than in those from healthy controls. Because early inoculations caused the most detrimental effects, the 1st mo. after transplanting should be considered the most critical period for PVY infection.
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    VERTICILLIUM WILT, A LIMITING FACTOR FOR TOBACCO PRODUCTION IN CHILE
    (1989) LATORRE, BA; LOLAS, M; MARHOLZ, G
    A wilt and orange-to-yellow discoloration observed in recent years in burley types of tobacco [Nicotiana tabacum] in Chile was confirmed to be caused by Verticillium dahliae. Disease incidence as high as 25.6% had occurred. Significant yield losses were estimated in nine of 11 selected plots during the 1987-1988 growing seasons. Quality also was significantly affected in diseased versus symptomless cultivar Burley-49 tobacco plants. Isolates of V. dahliae from tobacco were pathogenic to plants of tobacco cultivar Burley-21. However, only mild symptoms occurred in cultivar Coker-86; flue-cured lines V-1 and V-3 appeared to be resistant. All isolates were pathogenic to the susceptible tomato cultivar Earlypak-7, and some isolates caused symptoms on tomato seedlings of the resistant cultivars San Remo, Flora Dade, and Cal-Ace. Lower disease incidence was observed in the latter cultivars. Consequently, isolates from tobacco appeared to be race 1 of V. dahliae.