Residue Management, Seed Production, Crop Development, and Turf Quality in Diverse Kentucky Bluegrass Germplasm
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 nonthermal residue management, and relate seed yield and turf quality factors. Compared with 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 per panicle and fertile panicles per square meter were positively correlated with yield, lower yield with nonthermal residue management was closely associated with panicles per square meter. For six of the 15 highest-yielding entries, no significant difference was found between yield in the burned and residue-removed treatments, showing the dependence of yield on genotype under different residue management systems. Turf quality was negatively correlated with yield (r = −0.48, P < 0.01, n = 44) and seeds per panicle (r = −0.55, P < 0.01, n = 44). However, panicles per square meter were not significantly correlated with turf quality, so indirect selection for yield through genotypes with high panicles per square meter in the absence of high seeds per panicle should have minimal impact on turf quality. Sufficient variation for seed production appears available to encourage development of germplasm for nonthermal management systems.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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