Responses of Seed Yield Components to the Field Practices for Regulating Seed Yield of Smooth Bromegrass (Bromus inermis Leyss.)

Agronomic practices improve seed yield by regulating seed yield components, and the relationship between seed yield and seed yield components is still unclear in smooth bromegrass (Bromus inermis). To optimize seed production and yield in smooth bromegrass, a five-year field trial was designed with split-split-plot to study the combined effects of row spacing (30, 45, 60, and 75 cm), phosphorus (0, 60, 90, and 120 kg P ha−1) and nitrogen (0 and 100 kg N ha−1) on seed yield and seed yield components including fertile tillers m−2 (FTs), spikelets per fertile tiller (SFT), florets per spikelet (FS), and seeds per spikelet (SS). The results showed that FTs as a key factor had a positive effect to seed yield with the biggest pathway coefficient, while SS had a negative effect. Meanwhile, an interaction effect between FTs and SS was observed. FS and SS were increased with phosphorus application under the condition of sufficient nitrogen. In addition, sufficient precipitation at the non-growing season resulted in more FTs in the next year in rain-fed regions. Therefore, the optimum seed yield of smooth bromegrass can be obtained with row spacing (45 cm), nitrogen (100 kg N ha−1), and phosphorus application (60 kg P ha−1).

Sustainability assessment of the resistance of smooth bromegrass varieties to the causative agent of helminthosporiosis on an artificial infectious background

Smooth bromegrass (Bromopsis inermis Holub.) is widespread perennial grass and high quality feed. It is characterized by hight frost resistance. The main direction in breeding work is breeding of varieties with high seed productivity and with increased resistance to diseases. The research was carried out using an artificial infectious background in the immunology laboratory in FWRC FPA (previously, the All-Russian Williams Fodder Research Institute). This research took place in Lobnya, Mytishchi district, Moscow region, in 2018 -2020 years. Long-term phytosanitary monitoring of crops showed that the most common disease of this culture is brown leaf spot (helminthosporium). Seed germination decreases by 21-41% to this patgen. 16 samples of smooth bromegrass was planted in the artificial infectious background to determine their disease resistance in 2018 According to the study carried out, it was found that the disease reaches its peak at the stage of seed ripening. Sample # 2 and sample # 12 on average exceeded the standard variety Fakelny by 12% for resistance to pathogens of helminthosporiosis (among the studied samples, according to three-year data). Sample # 2 and sample # 12 can be recommended for inclusion in the breeding process to create modern intensive type varieties.

Yield and Some Quality Properties of Binary Alfalfa-Grass Mixtures in Different Mixture Ratios

The aim of this investigation was to determine appropriate perennial grasses and their most suitable mixture ratios, which can be grown with alfalfa in binary mixtures. The research was conducted during 2009-2011 in Isparta (37.50 °N, 30.32 °E), located in the Western Mediterranean climate conditions. In the study, alfalfa was planted as a binary mixture with perennial ryegrass (Lolium perenne L.), orchardgrass (Dactylis glomerata L.), meadow fescue (Festuca pratensis Huds.), and smooth bromegrass (Bromus inermis Leyss.) in a randomized block design with three replications. Sowing ratios of alfalfa in the mixtures varied 20, 30, and 40%, and grass species ratios were 80, 70, and 60%. In the study, significant differences were found among the applications regarding hay yield, crude protein content, crude protein yield, NDF, ADF, land equivalent ratio (LER), and grass ratio in the hay (GR). The highest hay yield was obtained from alfalfa + orchardgrass and alfalfa + smooth bromegrass binary mixtures (25.98 and 25.78 t ha-1, respectively). Alfalfa + perennial ryegrass and alfalfa + meadow fescue mixtures gave the highest crude protein contents as 14.93 and 14.80%, respectively. The highest LER values were observed on perennial ryegrass and smooth bromegrass binary mixtures, and the highest grass ratios were determined in orchardgrass and smooth bromegrass mixtures made with alfalfa. Increasing the alfalfa sowing ratio in the mixtures positively affected all quality characteristics such as crude protein, NDF, and ADF. It was concluded that orchardgrass and smooth bromegrass binary mixtures with alfalfa produced high yield and quality hay and that the mixture should contain 40% alfalfa and 60% grass.

Genome-wide Association Study Revealed Loci Linked to Post-drought Recovery and Traits Related to Persistence of Smooth Bromegrass (Bromus Inermis)

Association analysis has been proved as a powerful tool for genetic dissection of complex traits. This study was conducted to identify marker–trait associations for recovery, persistence, and as well as finding stable associations. In this study, a diverse panel of polycross derived progenies of smooth bromegrass was phenotyped under normal and water stress, during three consecutive years. Association analysis was performed between nine important agronomic traits along with three seasonal growth activity indices based on 535 SRAP markers. Population structure analysis identified five main subpopulations possessing significant genetic differences. Association analysis using mixed linear mode1 identified 339 and 233 marker-trait associations under normal and water stress environments, respectively. Some of these markers were associated with more than one trait; which can be attributed to pleiotropic effects or to a number of tightly linked genes affecting several traits. If the effectiveness of these markers in genetic control of these traits is validated, they could be potentially used for initiation of marker-assisted selection and targeted trait introgression of smooth bromegrass under normal and water stress environments.

Genome-wide association study revealed loci linked to post-drought recovery and traits related to persistence of smooth bromegrass (Bromus inermis)

Association analysis has been proved as a powerful tool for genetic dissection of complex traits. This study was conducted to identify marker – trait associations for recovery, persistence, and as well as finding stable associations. In this study, a diverse panel of polycross derived progenies of smooth bromegrass was phenotyped under normal and water stress, during three consecutive years. Association analysis was performed between nine important agronomic traits along with three seasonal growth activity indices based on 535 SRAP markers. Population structure analysis identified five main subpopulations possessing significant genetic differences. Association analysis using mixed linear mode1 identified 339 and 233 marker-trait associations under normal and water stress environments, respectively. Some of these markers were associated with more than one trait; which can be attributed to pleiotropic effects or to a number of tightly linked genes affecting several traits. If the effectiveness of these markers in genetic control of these traits is validated, they could be potentially used for initiation of marker-assisted selection and targeted trait introgression of smooth bromegrass under normal and water stress environments.

157 Effects of Monensin and Protein Type on Performance of Yearling Steers Grazing Smooth Brome

A two-yr study was conducted to evaluate the effects of monensin on sparing ruminal degradable protein in yearling steers grazing smooth bromegrass pastures (n = 288, initial BW = 332 kg, SD = 7). Treatment design was a 2 x 3 factorial with the following factors: 1) 0 or 200 mg monensin/steer daily; 2) no protein supplement, 1.25 kg soybean meal (SBM) as a source of RDP, or 1.31 kg non-enzymatically browned SBM as a source of RUP. Steers receiving supplemental protein were provided isonitrogenous amounts equivalent to dried distillers grains plus solubles at 0.50% BW. Steers were weighed approximately every 34 d to adjusted the amount of protein supplement. There was no interaction (P > 0.41) of monensin by protein type for average daily gain (ADG). Rate of gain for steers supplemented monensin was not different (P = 0.26) from steers not supplemented monensin. However, monensin supplemented steers numerically gained 7.9% more than steers not provided monensin when no supplemental protein was provided. Compared to steers supplemented with no protein, supplementing RDP increased ADG by 0.19 kg/steer (P < 0.001). Likewise, RUP supplementation increased ADG by 0.24 kg/steer (P < 0.001) compared to steers supplemented no protein. Supplementing RUP increased ADG by 0.05 kg/steer (P < 0.001) compared to steers supplemented RDP. Supplementing protein, especially rumen undegradable protein, improved yearling steer rate of gain on smooth bromegrass pastures. Monensin supplementation did not improve rate of gain. These data do not support the protein-sparing effects of monensin for steers supplemented with RDP.

Marker-trait association analysis for drought tolerance in smooth bromegrass

Background Little information is available on the application of marker-trait association (MTA) analysis for traits related to drought tolerance in smooth bromegrass. The objectives of this study were to identify marker loci associated with important agronomic traits and drought tolerance indices as well as fining stable associations in a diverse panel of polycross derived genotypes of smooth bromegrass. Phenotypic evaluations were performed at two irrigation regimes (normal and deficit irrigation) during 2 years; and association analysis was done with 626 SRAP markers. Results The results of population structure analysis identified three main subpopulations possessing significant genetic differences. Under normal irrigation, 68 and 57 marker-trait associations were identified using general linear model (GLM) and mixed linear mode1 (MLM), respectively. While under deficit irrigation, 61 and 54 markers were associated with the genes controlling the studied traits, based on these two models, respectively. Some of the markers were associated with more than one trait. It was revealed that markers Me1/Em5–11, Me1/Em3–15, and Me5/Em4–7 were consistently linked with drought-tolerance indices. Conclusion Following marker validation, the MTAs reported in this panel could be useful tools to initiate marker-assisted selection (MAS) and targeted trait introgression of smooth bromegrass under normal and deficit irrigation regimes, and possibly fine mapping and cloning of the underlying genes and QTLs.