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Oxidant Injury to Shade Tobacco Cultivars Developed in Connecticut for Weather Fleck Resistance 1
Author(s) -
Menser H. A.,
Hodges G. H.
Publication year - 1972
Publication title -
agronomy journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.752
H-Index - 131
eISSN - 1435-0645
pISSN - 0002-1962
DOI - 10.2134/agronj1972.00021962006400020019x
Subject(s) - cultivar , ozone , horticulture , nicotiana tabacum , air pollutants , biology , chemistry , air pollution , gene , ecology , organic chemistry , biochemistry
Thirteen tobacco ( Nicotiana tabacum ) cultivars developed by the cigar industry for resistance to weather fleck in Connecticut were tested at Beltsville, Md. for their responses to air pollutants. We sought information concerning the degree of fleck resistance among the new cultivars under conditions of high oxidant stress. Most of the improved cultivars showed significantly more resistance to ozone than ‘AST‐C’ (Bel‐C), a cultivar no longer grown because of its susceptibility to weather fleck. Two‐hour fumigations at 10 pphm ozone inflicted less than 10% injury on commercial cultivars. The same dosage injured about 20% of the leaf surfaces of Bel‐C. The increase in leaf injury to the commercial cultivars was more pronounced between ozone rates of 15 and 20 pphm, compared to 10 and 15 pphm. Ozone used at 20 and 25 pphm produced about 25% injury on the two most resistant selections, ‘GC 18’ and ‘CCC‐L.’ The same rates destroyed 60 to 70% of the leaves of Bel‐C. Weather fleck evaluations in the field disclosed that photochemical oxidants injured less than 3% of the leaf area of three commercial cultivars, but damaged 55% of the leaf surfaces of Bel‐C. The most leaf injury to an improved cultivar was 25%. Improved cultivars displayed less than 20% fleck damage in the first and second harvest primings, compared to 75% damage in the same two primings of Bel‐C. Results clearly demonstrate the success achieved in controlling weather fleck by using plant breeding methods.