Characterizing genetically diverse blue grama [Bouteloua gracilis (Willd. ex Kunth) Lag. ex Griffiths] seed sources

The need for regionally adapted native grass seed sources for the northern Great Plains has resulted in the commercial release of a range of plant materials, including ecovars™ 1 . Ecovars™ are multisite composite populations developed to combine broad genetic diversity from a geographic region. The objective of this study was to determine whether morphological data could be used to distinguish between genetically diverse blue grama [Bouteloua gracilis (Willd. ex Kunth) Lag. ex Griffiths] seed sources through classical statistical methods. Entries included a Manitoba (MB) ecovar™, a USDA–NRCS released cultivar ‘Bad River’, and ecotypes from Wyoming and Minnesota. Vegetative and reproductive measurements and ratings were taken from a spaced-plant nursery during 2000–2001 in Carman, Manitoba, Canada. The results were analyzed using statistical techniques including: ANOVA, least significant difference, canonical discriminant analysis (CDA), and coefficients of variation. These techniques distinguished four genetically diverse seed sources from each other through CDA. As hypothesized, there was greater within-population genetic diversity for the MB ecovar™ and Wyoming and Minnesota ecotypes, compared with ‘Bad River’. Our results indicate that genetically diverse blue grama seed sources can be distinguished, based on phenotypic measurements.

Opposing effects of bacterial endophytes on biomass allocation of a wild donor and agricultural recipient

ABSTRACT Root endophytes are a promising tool for increasing plant growth, but it is unclear whether they perform consistently across plant hosts. We characterized the blue grama (Bouteloua gracilis) root microbiome using two sequencing methods, quantified the effects of root endophytes in the original host (blue grama) and an agricultural recipient, corn (Zea mays), under drought and well-watered conditions and examined in vitro mechanisms for plant growth promotion. 16S rRNA amplicon sequencing revealed that the blue grama root microbiome was similar across an elevation gradient, with the exception of four genera. Culturing and Sanger sequencing revealed eight unique endophytes belonging to the genera Bacillus, Lysinibacillus and Pseudomonas. All eight endophytes colonized corn roots, but had opposing effects on aboveground and belowground biomass in each plant species: they increased blue grama shoot mass by 45% (19) (mean +/− SE) while decreasing corn shoot mass by 10% (19), and increased corn root:shoot by 44% (7), while decreasing blue grama root:shoot by 17% (7). Furthermore, contrary to our expectations, endophytes had stronger effects on plant growth under well-watered conditions rather than drought conditions. Collectively, these results suggest that ecological features, including host identity, bacterial traits, climate conditions and morphological outcomes, should be carefully considered in the design and implementation of agricultural inocula.

Responses of Ornamental Grass and Grasslike Plants to Saline Water Irrigation

Ornamental grasses are popular in urban landscapes in Utah and the Intermountain West United States, one of the driest and fastest growing regions in the United States. This experiment evaluated the responses of five ornamental grass species [blue grama (Bouteloua gracilis), indian sea oats (Chasmanthium latifolium), ‘Blue Dune’ sand ryegrass (Leymus arenarius), pink muhly grass (Muhlenbergia capillaris), ‘Foxtrot’ fountain grass (Pennisetum alopecuroides)] and two ornamental grasslike species [fox sedge (Carex vulpinoidea), common rush (Juncus effusus)] to saline irrigation water in a greenhouse. Plants were irrigated weekly with a nutrient solution at an electrical conductivity (EC) of 1.2 dS·m–1 (control) or saline solutions at an EC of 5.0 or 10.0 dS·m–1. At the first harvest (9 weeks after the initiation of treatment), sand ryegrass, pink muhly grass, and fountain grass irrigated with solutions at an EC of 5.0 and 10 dS·m–1 had good visual quality with no or minimal foliar salt damage; however, the remaining species exhibited slight or moderate foliar salt damage. There were no significant differences in shoot dry weight (DW) among treatments within any species, except fox sedge and fountain grass. At the second harvest (18 weeks after the initiation of treatment), sand ryegrass, pink muhly grass, and fountain grass still had no or minimal foliar salt damage, and indian sea oats and fox sedge exhibited slight or moderate foliar salt damage. Compared with the control, all species irrigated with solutions at an EC of 10.0 dS·m–1 had reduced shoot DWs with the exception of blue grama. However, only common rush and pink muhly grass irrigated with solutions at an EC of 5.0 dS·m–1 had lower shoot DWs than the control. These results demonstrated that seven ornamental grass or grasslike species had a very strong tolerance to the salinity levels used in the 4-month experiment. Although plant growth was inhibited as a result of saline irrigation, plant visual quality of sand ryegrass, pink muhly grass, and fountain grass was still acceptable. These three species appear to be more suitable for landscapes in which saline irrigation water is used. Further research is needed to evaluate more ornamental grasses for landscapes in salt-prone areas and nearby coastal regions.

Establishment of Native Grasses with Biosolids on Abandoned Croplands in Chihuahua, Mexico

The objective of the work was to evaluate establishment and forage production of native grasses with application of biosolids, a byproduct of waste-water treatment, at an abandoned field, in Ejido Nuevo Delicias, Chihuahua, Mexico. Four biosolids rates from 0 (control) to 30 dry Mg ha−1and two methods of application, surface applied (BioSur) and soil incorporated (BioInc), were evaluated. Seedbed preparation included plowing and harrowing before rainfall. Field plots of 5 × 5 m were manually sown with a mix of blue grama (Bouteloua gracilis) (50%) and green sprangletop (Leptochloa dubia) (50%) in early August 2005. Experimental design was a randomized block with a split plot arrangement. Grass density, height, and forage production were estimated for three years. Data were analyzed with mixed linear models and repeated measures. Green sprangletop density increased under all biosolids rates regardless of method of application, while blue grama density slightly decreased. Biosolids were more beneficial for green sprangletop height than for blue grama height. Blue grama forage production slightly increased, while green sprangletop forage production increased the most at 10 Mg ha−1biosolids rate under BioSur method. It was concluded that BioSur application at 10 and 20 Mg ha−1rates had positive effects on the establishment and forage production of native grasses, especially green sprangletop.

Residual Effects of Biosolids Application on Forage Production of Semiarid Grassland in Jalisco, Mexico

Single application of biosolids increases forage production on semiarid grasslands. Residual effects of biosolids on forage production have been scarcely measured in semiarid grasslands. The objective was to evaluate the residual effects of biosolids application on forage production of blue grama (Bouteloua gracilis(Willd. ex Kunth) Lag. ex Griffiths) and other grasses at a semiarid grassland in Jalisco, Mexico. The study was performed at shortgrass prairie in northeast Jalisco. Field plots were selected to include blue grama plants before rainy season in 2002. Aerobic biosolids were applied at 0 (control), 15, 30, 45, 60, 75, or 90 dry Mg ha−1under a completely random design with five replications. Forage production was estimated by clipping at the end of the growing season during five years. Data analysis was performed with linear mixed model and repeated measures. Forage production was influenced by a rate × year × species interaction (P=0.0001). Blue grama forage production increased with increasing biosolids rates during all years, with the magnitude of this response varying among years. Forage production of other grass species slightly decreased with biosolids application. Single biosolids application had a residual effect on forage production throughout five years in semiarid grasslands.