Overseed Home Lawn Variety Trials 2006-2007

Abstract

Spring transition (from ryegrass to bermudagrass) has been problematic for the last 20 years based on, in part, improved heat tolerance and lower growing cultivars of perennial ryegrass. Annual ryegrass is used sparingly for commercial properties and for home owners in southern Arizona. Hybrid ryegrass (cross between perennial and annual ryegrass) has been manufactured by seed companies in an effort to improve the transition of a grass used specifically for overseeding, with improved turf grass attributes over those of annual ryegrass. A field test was conducted to evaluate several hybrid ryegrasses, two improved annual ryegrasses, and Gulf annual ryegrass under homeowner conditions. The true annuals produced the quickest amount of ground cover in the shortest period of time. By early December, all plots had 98% or more cover, with FH having 95% cover. Transend, Transport and 041 Lh had consistently high quality scores throughout most of the 8 month test, with Transport and 04 1 LH scoring for fair turfgrass quality into mid June. Sprint annual ryegrass had excellent turfgrass quality scores in November and December, however, scores declined substantially in April and afterwards. After emergence and into early December, Transport and 041LH clearly had the darkest turf coloration, with 041LH producing a turf with a color intensity typical of medium green perennial ryegrass. Gulf and FH were noticeably lighter in color. Gulf, Sprint and Transcend developed ring/patch type disease symptoms in early February 2007, while others did not. "Stemminess" ratings in late spring (a time at which annual ryegrass is typically pronouncedly so) showed that FH intermediate and Gulf produced the most "stemmy" turfs, followed by Sprint annual. Transport and 041LH showed hardly any seed head culm development, with Transcend being intermediate. Interestingly, not all the entries which generally had the highest numerical rankings for density, texture, uniformity and overall turfgrass quality, had the highest percent plot living overseed during transition. Entry 041LH had 30% overseed, 46% bermuda, and 24% straw. Transcend had 16% overseed, 25% straw and59% straw on June 12. Transport had the highest retention of green overseed (72%), with 23% bermuda and 5% bare ground or straw plot cover. Sprint had 19% overseed, 20% live bermudagrass, and 61% bare straw plot cover, more so than that of Gulf. Final quality scores showed that 041LH and Transport had the best quality mean rank values, with all others having low quality scores on 12 June just prior to scalping to fully reconstitute the underlying Tifway bermudagrass. This shows vast improvements in turfgrass performance for INTERMEDIATES, which previously (and again) show near full acceptability in most turfgrass attributes, and now show enhanced color. Likewise, improvements in strict annual types show improved turf quality (Sprint) over Gulf.