Improving tall fescue shade tolerance: identifying candidate genotypes

摘要

Tall fescue (Schedonorus arundinaceus [Schreb.] Dumort.) is genetically variable for many agronomic traits, so it might be possible to increase its persistence and productivity in shaded agroforestry applications. The objective of this research was to identify high yielding, shade-tolerant genotypes. Seed was obtained from eight families: seven plant introductions of European origin: 234718, 234720, 234882, 234884, 235018, 235019, 235036, and one cultivar (Kentucky 31). Two sequential experiments were conducted to select genotypes for dry mass yield during April-September. Experiment 1 included 30 genotypes of each of the eight families randomly assigned to each of two microenvironments: artificially shaded with fabric and unshaded. Maximum and minimum yields were 93.9 and 47.1 g familyp# for Kentucky 31 and 235036, respectively. After 1 year in Experiment 1, there were more survivors in the unshaded than shaded environment (0.40 and 0.09, respectively), ranging from 0 to 0.56 (235036 and Kentucky 31, respectively). Forty robust genotypes from four families (234718, 234720, 235019, and Kentucky 31) were selected from shaded and unshaded microenvironments of Experiment 1, clonally propagated, and evaluated in pots for 2 year in Experiment 2. Shade-selected Kentucky 31 yielded more (31.0 g plantp#) in shade than other shade-selected families (25.2-25.8 g plantp#). Eleven genotypes in the top quartile (yield E33.0 g plantp#) were selected for further testing. All genotypes were endophyte (Neotyphodium coenophialum Morgan-Jones and Gams)-infected. Further testing is needed to measure heritability of yield in shaded, water-deficit conditions of a tree understory.