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Correlation of Greenhouse Inoculations of Longleaf Pine with Cronartium quercuum f. sp. fusiforme with Field Ranking of Resistance. R. L. Anderson, Resistance Screening Center, USDA Forest Service, Asheville, NC 28802. C. H. Walkinshaw, USDA Forest Service, Southern Forest Experiment Station, Gulfport, MS 39503. Plant Dis. 73:859. Accepted for publication 7 July 1989. Copyright 1989 The American Phytopathological Society. DOI: 10.1094/PD-73-0859A.

In 1987, seed from 27 wind-pollinated longleaf pines with known field resistance to fusiform rust (caused by Cronartium quercuum (Berk.) Miy. ex Shirai f. sp. fusiforme) and two loblolly checks were inoculated at the Resistance Screening Center (1). The field data for percent trees galled ranged from 0 to 38%. In the greenhouse, all seed lots had some trees with fusiform rust symptoms (e.g., galls, multiple buds, or internal necrotic tissue). For longleaf, the lowest was 3% and the highest was 28%. Galls were found on 44 and 53% of the seedlings in the two checks. Analysis of variance and Duncan's multiple range test (0.05 level) showed significant variations in rust incidence associated with seed lot but not by test or an interaction of test and seed lot. The greenhouse and field data were highly correlated (r2 = 0.79).

Reference: (1) R. L. Anderson and C. H. Walkinshaw. Plant Dis. 70:50, 1986.