ABSTRACTNonflowering or sparse flowering orchardgrass (Dactylis glomerata L.) would greatly simplify management of intensive rotational grazing systems. Our objective was to quantify seed production on nonflowering orchardgrass clones selected in cold‐winter climates, but grown for seed in mild‐winter climates. We evaluated 98 orchardgrass clones for seed production traits at four locations. Most plants (∼92%) flowered at the three northern locations, but only 38% flowered at Parlier, which may have a winter insufficiently cold for adequate floral induction and vernalization. Mean panicle number was lowest (11%) for plants selected at the location with the warmest winter conditions, and highest (37%) for plants selected at the location with the coldest winter conditions. These results confirm our expectations that the most desirable plants (nonflowering under cold winters and normal flowering under mild winters) should arise from selection under more severe winters. Selection for nonflowering under mild winter conditions simply leads to nonflowering plants under all conditions. These results demonstrate that individual orchardgrass genotypes are capable of dual phenotypic expression, flowering in mild‐winter climates or expressing the nonflowering trait in cold‐winter climates and that the expression of this trait depends on both the selection and evaluation location.

Orchardgrass (Dactylis glomerata L.) is a valuable pasture species in much of temperate humid North America. However, profuse and early flowering in spring creates management problems for graziers and reduces intake of livestock in a management-intensive rotational grazing system. The objectives of this study were to estimate environmental stability, genotypic variability, and frequency of nonflowering and sparse-flowering plants in two sparse-flowering orchardgrass populations. Seven cultivars and 299 half-sib families were evaluated for 2 yr at five locations between 42degrees and 47degreesN latitude. Sparse-flowering populations WO-SF-B and WO-SF-C were later in maturity, produced fewer panicles per plant, and had higher frequencies of sparse-flowering and nonflowering plants than the cultivars. Plants had varying levels of expression of the nonflowering trait, ranging from slightly sensitive (sparse flowering in one year) to highly sensitive (stable nonflowering across years), with highly sensitive plants found only within populations WO-SF-B and WO-SF-C. The nonflowering trait of orchardgrass appears to be controlled by floral-regulation genes that are turned off by short-day temperatures below a critical threshold. Such a threshold appears to exist for all orchardgrass plants, but is increased in those plants expressing the nonflowering trait.

Simultaneous improvement of forage traits and seed yield in orchardgrass (Dactylis glomerata L.) has been problematic because of geographic separation of forage and seed production locations. Previous work has shown that a complex multilocation selection program in forage production environments can increase forage yield as well as seed yield in Oregon. The objective of this experiment was to compare target-environment (TE) and nontarget-environment (NTE) selection approaches for increasing seed yield of orchardgrass in Oregon. Two cycles of recurrent phenotypic selection for panicle seed mass (PSM) and agronomic traits were conducted on four populationsin four eastern USA locations (NTE) and one Oregon location (TE). Seed yield was increased in three of four orchardgrass populations by TE selection, averaging 5.1% cycle(-1), but was improved by NTE selection in only one of four populations. Conversely, TE selection for PSM and agronomic traits resulted in no changes to forage yield in the eastern USA and Canada, while NTE selection for PSM and agronomic traits increased forage yield in two of four populations, confirming results of a previous study. It appears that the most efficient system for simultaneously improving forage and seed traits of orchardgrass would be to practice selection for forage traits in forage production environments and seed traits in seed production environments, with sufficiently large populations to allow multitrait selection.

Crop ScienceVolume 38, Issue 5 cropsci1998.0011183X003800050053x p. 1402-1402 Registration of Cultivars Registration of ‘Albert’ Orchardgrass Micheal D. Casler, Micheal D. CaslerSearch for more papers by this authorDavid A. Sleper, David A. SleperSearch for more papers by this authorIrving T. Carlson, Irving T. CarlsonSearch for more papers by this authorClyde C. Berg, Clyde C. BergSearch for more papers by this authorReed E. Barker, Reed E. BarkerSearch for more papers by this author Micheal D. Casler, Micheal D. CaslerSearch for more papers by this authorDavid A. Sleper, David A. SleperSearch for more papers by this authorIrving T. Carlson, Irving T. CarlsonSearch for more papers by this authorClyde C. Berg, Clyde C. BergSearch for more papers by this authorReed E. Barker, Reed E. BarkerSearch for more papers by this author First published: 01 September 1998 https://doi.org/10.2135/cropsci1998.0011183X003800050053xCitations: 1AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL No abstract is available for this article.Citing Literature Volume38, Issue5September–October 1998Pages 1402-1402 RelatedInformation

Limited information is available on genotype‐environment (GE) interactions of dry matter yields in reed canarygrass (Phalaris arundinacea L.). We measured forage yield on 60 clones of reed canarygrass for 3 years in Minnesota, Iowa, Wisconsin, and North Dakota, 2 years in Missouri, and 1 year in South Dakota. Objectives were to determine the magnitude of GE interactions for forage yield testing, to characterize testing environments, to determine an efficient allocation of testing sites, and to ascertain effectiveness of stability parameters in selecting clones for breeding programs. Significant genetic differences were found for harvest 1, regrowth, and season total dry matter yields. Genotype ✕ location and genotype ✕ location ✕ year variances were significant, whereas genotype ✕ year interactions were not. Location and genotype ✕ location effects were inconsistent among years. Year ✕ location interactions were very large in relation to all other sources of variation. Correlations of clonal mean total dry matter yields among locations and resultant cluster analyses indicated that la. and Mo. should represent the minimum number of yield testing sites. Iowa had a high value as a testing site whereas Mo. was intermediate. North Dakota and/or S. Dak. could be added if additional information is desired on broader adaptability and to identify superior genotypes for these locations. Consistent conclusions regarding clonal performance could not be drawn from the stability parameters b, r2, and sy.x. Mean yields per se appeared to be the most useful in determining genetic yield potential.

Our objectives were to estimate genotypic and environmental variances and heritability of indole alkaloid concentration in reed canarygrass (Phalaris arundinacea L.) The variance component estimates for genotype ✕ environment and genotype ✕ cutting interactions were significant but small as compared to the estimate for genetic variance among 31 unrelated clones of diverse origin. Genotype ✕ environment ✕ replication in environments interactions were statistically nonsignificant. Thus, variation in alkaloid concentration was largely associated with genotypes.Heritability studies included 36 clones and their 18 two‐clone crosses grown at 2 locations. Heritability estimates from the second cutting were higher than corresponding estimates from the third cutting. Combining data from two regrowth cuttings in one season reduced the bias introduced as a result of sampling the forage at different growth stages. When based on parents in the 0.17 to 1.37% overall alkaloid concentration range, realized heritability estimates for the combined August and September cuttings ranged from 0.67 to 0.72. All heritability estimates were slightly higher for the high alkaloid concentration range compared to estimates for the low range. Narrow‐sense heritability estimates were nearly as large as the corresponding broad‐sense estimates; thus, total genetic variance was largely additive. Parent‐offspring regression analyses of identical materials confirmed this conclusion. Our results suggest that genetic gain in alkaloid concentration can be realized from selection among individual plants.