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Differential Summer Suvival of White Clover Stolons: Germplasm and Fungicide Effects

Pederson, G. A., Pratt, R. G.
Crop science 1995 v.35 no.5 pp. 1282-1287
Trifolium repens, summer, dormancy, drought, drought tolerance, stolons, mortality, benomyl, cultivars, germplasm, disease resistance, genetic resistance, fungal diseases of plants, disease control, plant diseases and disorders, genotype, Mississippi
White clover (L.) stands in the southeastern USA survive during summer drought predominantly through persistence of stolons. The decay and death of stolons during the hot, humid summer may be partially due to fungal diseases. This study determined the effect of summer fungicide applications on stolon survival of ‘Regal’ and ‘Louisiana S-’ white clover compared with drought-tolerant Brown Loam Syn. No. 2 germplasm (BLSyn). The three white clover entries were grown in the field on a Catalpa silty day (fine, montmorillonitic, thermic Fiuvaquentic Hapludoll) at Mississippi State, MS, in three separate 1-yr studies. During summer stolon dormancy, plots of each entry were either untreated or sprayed biweekly with benomyl [methyl 1-(butylcarbamoyl)-2-benzimidazole-carbamate]. In 2 of 3 yr, BLSyn had 23 to 63% greater ground cover, 33 to 55% greater stolon density, and 30 to 47% greater relative live stolon length following the summer drought than Louisiana S-1. In all 3 yr, BLSyn had greater relative live stolon length (7-18%) following the summer drought than Regal. Plots treated with benomyl had 14 to 52% greater stolon density (in 2 of 3 yr), 14 to 40% greater stolon growing point density, and to 27% greater relative live stolon length than untreated plots. Benomyl treatment gave less of an increase in relative live stolon length of BLSyn than in the two cultivars. These results suggest that fungal pathogenesis may reduce white clover stolon survival during summer dormancy, and that greater fungal disease resistance could be part of the mechanism of improved summer survival in BLSyn white clover.