E. C. Brummer

Tall Fescue Response to Nitrogen and Harvest Date for Stockpiled Grazing in the Upper Midwest

Tall fescue (Festuca arundinacea Schreb.) is a cool-season grass with physiological and morphological traits suitable for stockpiled grazing. The effect of late summer nitrogen (N) application was measured for yield and quality responses using four N rates (0, 25, 50, and 100 lb/acre) and three autumn harvest dates. Averaged across harvest date, linear increases of dry matter (DM) occurred in 1999 and 2000. In 1999, yield = 1747 + 15 × N rate (R 2 = 0.92, RMSE = 235) and in 2000, yield = 672 + 19 × N rate (R 2 = 0.96, RMSE = 202). Year by harvest date and year by N rate interactions were observed for yield because of above average rainfall in 1999 and below average rainfall in 2000. Forage crude protein (CP) and in vitro dry matter digestibility (IVDMD) increased as N rate increased, while neutral detergent fiber (NDF) decreased. Year by harvest date interactions were observed for CP, NDF, and IVDMD, and year by N rate interactions were observed for CP and NDF. Late summer N application increased DM yield and CP of the first cutting the following spring. Forage producers who apply late-season N can increase the quantity and quality of tall fescue forage available for autumn grazing. However, yield and quality losses can occur if harvest is delayed beyond October.

Selection for Orchardgrass Seed Yield in Target vs. Nontarget Environments

tion interaction between the Pacific Northwest and the eastern USA is well documented for total seed yield Simultaneous improvement of forage traits and seed yield in or(TSY) of orchardgrass (Godshalk, 1984; Leudtke, 1984; chardgrass (Dactylis glomerata L.) has been problematic because of geographic separation of forage and seed production locations. Stratton and Ohm, 1989). The most successful orPrevious work has shown that a complex multilocation selection prochardgrass breeding programs in North America are gram in forage production environments can increase forage yield as those that utilize both forage and seed production enviwell as seed yield in Oregon. The objective of this experiment was ronments for simultaneous improvement of both comto compare target-environment (TE) and nontarget–environment modities (Casler et al., 2000). (NTE) selection approaches for increasing seed yield of orchardgrass Convergent-divergent selection, a method designed in Oregon. Two cycles of recurrent phenotypic selection for panicle to improve regional adaptation, is based on recurrent seed mass (PSM) and agronomic traits were conducted on four populaselection at a number of diverse locations, where seed tionsin four eastern USA locations (NTE) and one Oregon location used to begin each new cycle of selection at a specific (TE). Seed yield was increased in three of four orchardgrass populalocation is derived from selections made at a different tions by TE selection, averaging 5.1% cycle 1, but was improved by NTE selection in only one of four populations. Conversely, TE seleclocation (Lonnquist et al., 1979). Using two cycles of tion for PSM and agronomic traits resulted in no changes to forage convergent-divergent selection at four locations in the yield in the eastern USA and Canada, while NTE selection for PSM central and eastern USA, we previously demonstrated and agronomic traits increased forage yield in two of four populations, improved Oregon seed yield as a direct result of selecconfirming results of a previous study. It appears that the most efficient tion in two of four germplasm pools (Barker et al., system for simultaneously improving forage and seed traits of or1997). Selection, based on panicle seed mass (PSM) and chardgrass would be to practice selection for forage traits in forage agronomic traits associated with forage production, also production environments and seed traits in seed production environresulted in increased forage yield in these two germments, with sufficiently large populations to allow multitrait selection. plasm pools (Casler et al., 1997a). We concluded that convergent-divergent selection at a range of diverse nontarget locations was responsible for increasing the M forage crops, including orchardgrass, have frequency of a diverse array of alleles for seed productwo distinct commodities: forage and seed. Betion of orchardgrass, resulting in increased seed produccause orchardgrass cannot be grown for forage without tion in the target environment (Barker et al., 1997). first generating seed to be used for planting, these two Conversely, single-location selection for the same traits commodities are inextricably interdependent. As a forin the same germplasm pools resulted on no gains in age crop, orchardgrass is widely grown from eastern Oregon seed yield, likely because of the genotype Canada to the eastern and midwestern USA (Christie location interaction that exists between Oregon and the and McElroy, 1995). Orchardgrass is most widely grown eastern USA. as a seed crop in the Willamette Valley of Oregon, an These previous studies provided a critical comparison area uniquely suited for seed production of numerous of convergent-divergent selection with single-location perennial, cool-season grasses, because of its mild winselection as a control, effectively comparing progress ters, cool summers, and favorable timing of precipifor a multistate, collaborative effort vs. one breeder with tation. one selection location. However, these studies did not Because forage and seed production environments address the issue of selection in target vs. nontarget do not overlap, orchardgrass breeders are located within environments, providing a direct comparison between one or the other region. Because of the expense and the progress that could be achieved by a breeder in inconvenience of distant test sites, orchardgrass breedOregon vs. the multistate collaborative effort. To do ers have traditionally focused efforts on forage traits if this, we resampled the original germplasm pools and located in a forage production region and seed traits if practiced two cycles of single-location selection at a located in a seed production region. Thus, new cultivars representative location in Oregon. The objectives of bred in the eastern or central USA are not necessarily this study were to evaluate and compare two cycles good seed producers and vice versa. Genotype locaof recurrent phenotypic selection for increased panicle seed mass and agronomic traits using two selection M.D. Casler, USDA-ARS, U.S. Dairy Forage Research Center, Madimethods: convergent-divergent (multilocation) selecson, WI 53706-1108; R.E. Barker, USDA-ARS, National Forage Seed tion in nontarget environments vs. selection in a single Production Research Center, 3450 S.W. Campus Way, Corvallis, OR target location. 97331-7102; E.C. Brummer, Dep. of Agronomy, Iowa State Univ., Ames, IA 50010; Y.A. Papadopolous, Agriculture and Agri-Food Canada, Crops and Livestock Research Centre, 440 University Ave., MATERIALS AND METHODS Charlottetown, PEI, Canada C1A 4N6; L.D. Hoffman, Dep. of Agronomy, The Pennsylvania State Univ., State College, PA 16801. Received Germplasm 13 April 2002. *Corresponding author (mdcasler@facstaff.wisc.edu). Selection was practiced in four orchardgrass base populations, each derived as part of a breeding program in Iowa Published in Crop Sci. 43:532–538 (2003).