Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/1/2003
Publication Date: 5/1/2003
Citation: JOHNSON, R.C., JOHNSTON, W.J., GOLOB, C.T. RESIDUE MANAGEMENT, SEED PRODUCTION, CROP DEVELOPMENT, AND TURF QUALITY IN DIVERSE KENTUCKY BLUEGRASS GERMPLASM. CROP SCIENCE. 2003. v. 43. p. 1091-1099. Interpretive Summary: Air quality issues are making field burning of Kentucky bluegrass residue to stimulate seed production untenable. We investigated yield, yield components, and turf quality on a diverse set of forty-five Kentucky bluegrass entries under three different residue treatments. Unburned treatments generally yielded less than burned treatments as expected, but for six of the 15 highest yielding entries, burned and residue removed treatments did not differ significantly. Turf quality was negatively correlated with seeds panicle-1 but not with panicles m-2, suggesting that increasing yield through panicles m-2 would have minimal impact on turf quality. Sufficient variation for seed production appears available for developing germplasm for no-burn management systems.
Technical Abstract: Field burning has traditionally been used to stimulate Kentucky bluegrass (Poa pratensis L.) seed production, but air quality issues are making this practice untenable. Our objectives were to determine agronomic and crop developmental responses of 45 diverse Kentucky bluegrass entries under burned, mechanically removed, and residue retained management systems, assess the scope for improving yield under non-thermal residue management, and relate seed yield and turf quality factors. Compared to burned treatments, yield was reduced 27% when residue was mechanically removed from plots, and 63% when residue was retained. Higher yield was promoted by a long heading to anthesis period, a relatively short anthesis to harvest period, and an early harvest date (maturity). Although both seeds panicle-1 and fertile panicles m-2 were positively correlated with yield, lower yield with non-thermal residue management was closely associated with panicles m-2. For six of the 15 highest yielding entries, there was no significant difference between yield in the burned and residue removed treatments, showing the dependance of yield on genotype under different residue management systems. Turf quality was negatively correlated with yield (r= -0.48**, n=44) and seeds panicle-1 (r= -0.55**, n=44). However, panicles m-2 were not significantly correlated with turf quality, so indirect selection for yield through genotypes with high panicles m-2 in the absence of high seeds panicle-1 should have minimal impact on turf quality. Sufficient variation for seed production appears available to encourage development of germplasm for non-thermal management systems.