title: Flowering in Crimson Clover as Affected by Planting Date.
abstract: Understanding factors that affect flowering of crimson clover (Trifolium incarnatum L.) could improve management decisions to optimize utilization by improving season of use. The experiment was a split-plot randomized complete block design with three replications at College Station, TX, in the 1997-1998 and 1999-2000 growing seasons, and Overton, TX, in the 1998-1999 growing season. Main plot treatments of two crimson clover cultivars and subplot treatments of six planting dates (PDs) were used to evaluate the effect of date to reach 50% budding and 50% flowering based on day of year (DOY), days after planting (DAP), photothermal index (PTI), and growing degree days (GDD) under field conditions. Correlations with 50% bud and 50% flower were almost identical. 'Columbus' planted in the autumn flowered an average of 49 d later than 'Tibbee'. Date to reach 50% flowering was best correlated with DOY (r = 0.93 and 0.97) and DAP (r = 0.92 and 0.98) for Columbus and Tibbee. Date to reach flowering was not as highly correlated with PTI (r = 0.66 and 0.82) or GDD (r = 0.71 and 0.85) for Columbus and Tibbee, thus temperature could not be used to predict flowering. Planting after 21 December delayed flowering in Tibbee 2 to 9 wks, whereas, Columbus planted after 21 December did not flower. It is important to plant early in the growing season or to use later-maturing cultivars to maximize the length of the growing season and possible total production in grazed environments.
authors.affiliation: Texas A&M Univ. Agricultural Research and Extension Center, 1229 N HWY 281, Stephenville, TX 76401. Texas A&M Univ. Agricultural Research and Extension Center, P.O. Box 200, Overton, TX 75684-0200. Soil and Crop Science Dep., Texas A&M University, College Station, TX 77843. Dep. of Statistics, Texas A&M University, College Station, TX 77843.
authors.forename: Twain J.
authors.initials: TJ
authors.lastname: Butler
authors.forename: Gerald W.
authors.initials: GW
authors.lastname: Evers
authors.forename: Mark A.
authors.initials: MA
authors.lastname: Hussey
authors.forename: Larry J.
authors.initials: LJ
authors.lastname: Ringer