Submitted to: Sustainable Agriculture International Conference Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 1/1/2002
Publication Date: 1/1/2002
Citation: Johnson, R.C., Johnston, W.J., Golob, C.T. Evaluating genetic resources for sustainable production of Poa pratensis. Proceeding Second International Sustainable Agriculture Conference for Food, Energy, and Industry. Beijing, China. 2002. p. 1058-1064. 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 non-thermal management systems.
Technical Abstract: Field burning to remove post-harvest residue has traditionally been used to stimulate Kentucky bluegrass (Poa pratensis L.) seed production in the Pacific Northwest U.S.A. Air quality issues are, however, making this practice unsustainable. Forty-five diverse Kentucky bluegrass germplasm entries were compared in burned, mechanically removed, and residue retained management systems to assess the genetic potential for improving seed production under non-thermal management. In burned treatments, yield was reduced 27% when residue was mechanically removed from plots, and 63% when residue was retained. Although both seeds per panicle and fertile panicles per m2 were positively correlated with yield, lower yield with non-thermal residue management was most closely associated with panicles per m. For six of the 15 highest yielding entries, the difference between yield in the burned and the residue removed treatments was not significant, showing the dependence of genotype in the yield response 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 per m2 was not significantly correlated with turf quality, so indirect selection for yield through genotypes with high panicles per m2 in the absence of high seeds per panicle would be expected to have minimal impact on turf quality. Sufficient variation for seed production appears available to encourage development of improved germplasm for residue removed management systems.