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Screening St. Augustinegrass Genotypes for Brown Patch and Large Patch Disease Resistance
Author(s) -
Flor Norma C.,
Harmon Philip F.,
Kenworthy Kevin,
Raid Richard N.,
Nagata Russell,
Datnoff Lawrence E.
Publication year - 2017
Publication title -
crop science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.76
H-Index - 147
eISSN - 1435-0653
pISSN - 0011-183X
DOI - 10.2135/cropsci2016.06.0514
Subject(s) - biology , genotype , stolon , rhizoctonia solani , inoculation , plant disease resistance , veterinary medicine , horticulture , gene , genetics , medicine
Two diseases of St. Augustinegrass (SAG) [ Stenotaphrum secundatum (Walt.). Ktze.] are caused by different anastomosis groups (AGs) of Rhizoctonia solani . Brown patch (BP) is a foliar disease of little economic importance, and large patch (LP) causes leaf sheath rot and death of affected turfgrass shoots and stolons. St. Augustinegrass genotypes were inoculated with an isolate that causes BP and an isolate that causes LP in repeated experiments. Three disease severity parameters were calculated from data recorded from each genotype, including final disease severity ( Y ), area under the disease progress curve (AUDPC), and the apparent infection rate ( r L ). The inoculation protocol reliably produced symptoms, and both r L and AUDPC provided statistically significant separations between genotypes for their susceptibility to BP and LP. A significant interaction between isolate and genotype was observed, and some genotypes that were very susceptible to LP were among the least susceptible to BP. These data suggest that differences in resistance to LP can be quantified in SAG genotypes, but genotype response may be isolate dependent.