Morphometric characterization of oxbow lakes along the Black Warrior River, Southeastern United States

The yellows disease of cole crops, caused by Fusarium oxysporum f. sp. conglutinans, can be very damaging to collard. Growers in the southeastern United States frequently produce collard in hot, summer months when conditions for yellows development are favorable, and thus, incidence of this disease is increasing. A collection of essentially all U.S. commercial cultivars of collard, various landraces of collard, and other representative cole crops was evaluated for response to artificial inoculation with F. oxysporum f. sp. conglutinans under controlled-temperature conditions. In addition, the same collection was evaluated following transplanting for response to naturally infested soil in the field during summer 1997 and 1998. In all trials, genotype had the most significant effect on percentage of diseased plants, and genotype responses ranged from resistant (0 to 20% diseased) to susceptible (61 to 100% diseased). There was a significant temperature effect on percentage of diseased plants in one growth chamber experiment with five genotypes that resulted primarily from an increase in disease incidence for the cultivar Blue Max at 30°C compared with 25°C. Temperature was not significant in a second experiment with 20 genotypes. In the field, although significant differences were observed among genotypes and between years, a significant genotype × year interaction was not detected for percentage of diseased plants, indicating a similar ranking of genotypes for resistance between years. There was a significant correlation between results from controlled-environment studies and the field. A resistant response to F. oxysporum f. sp. conglutinans was expressed in certain cultivars of collard, including Flash, Heavicrop, and Morris Heading, and also in specific landraces. This resistance was stable in relatively high temperature environments used in evaluations. Results of this research indicate that choice of cultivar is a critical factor in producing collard where conditions favor infection by F. oxysporum f. sp. conglutinans. This information will aid in development of new yellows-resistant cultivars.

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A Survey of Chinese Plants of Potential Ornamental Value for the Southeastern United States

HortScience ◽

10.21273/hortsci.30.4.891a ◽

1995 ◽

Vol 30 (4) ◽

pp. 891A-891

Author(s):

Donglin Zhang ◽

F. Todd Lasseigne ◽

Michael A. Dirr

Keyword(s):

United States ◽

Southeastern United States ◽

Ornamental Plants ◽

The United States ◽

Southeastern China ◽

Climatic Zones ◽

History Of ◽

And Performance ◽

Species Performance

China, E.H. Wilson's “Mother of Gardens”, is a large untouched resource of ornamental plants to this day. Southeastern gardens and arboreta teem with plants from China, which boasts the most diverse temperate flora in the world with more than 30,000 species described. Because of China's unique geography, climate, and floristic similarities to the southeastern United States, many of these ornamental plants should be adaptable. Based on studies of the phytogeography, floristics, history of plan; hunting, and performance of plants already introduced into cultivation from central and southeastern China, ≈500 potentially “new” species of Chinese woody plants are presented for ornamental evaluation. Characterization of the species' geography and climatic preferences in China will allow horticulturists to more accurately predict the species' performance throughout the Southeast. Zone maps exist for the United States and China that equate geographic areas on a temperature basis. However, these zone maps do not reflect the wide microclimatic differences (such as those contributed by elevation) that occur in the climatic zones. The results of this survey should enhance interest in the wonderful diversity of Chinese plants. Maps of areas already explored in the past (George Forrest, Ernest H. Wilson, and other contemporary explorers) as well as maps of suggested areas which have not been fully botanized are presented for review.

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