Improving Grain Yield via Promotion of Kernel Weight in High Yielding Winter Wheat Genotypes

Improving plant net photosynthetic rates and accelerating water-soluble carbohydrate accumulation play an important role in increasing the carbon sources for yield formation of wheat (Triticum aestivum L.). Understanding and quantify the contribution of these traits to grain yield can provide a pathway towards increasing the yield potential of wheat. The objective of this study was to identify kernel weight gap for improving grain yield in 15 winter wheat genotypes grown in Shandong Province, China. A cluster analysis was conducted to classify the 15 wheat genotypes into high yielding (HY) and low yielding (LY) groups based on their performance in grain yield, harvest index, photosynthetic rate, kernels per square meter, and spikes per square meter from two years of field testing. While the grain yield was significantly higher in the HY group, its thousand kernel weight (TKW) was 8.8% lower than that of the LY group (p < 0.05). A structural equation model revealed that 83% of the total variation in grain yield for the HY group could be mainly explained by TKW, the flag leaf photosynthesis rate at the grain filling stage (Pn75), and flag leaf water-soluble carbohydrate content (WSC) at grain filling stage. Their effect values on yield were 0.579, 0.759, and 0.444, respectively. Our results suggest that increase of flag leaf photosynthesis and WSC could improve the TKW, and thus benefit for developing high yielding wheat cultivars.

Pasture resilience reflects differences in root and shoot responses to defoliation, and water and nitrogen deficits

The yield of a pasture is directly proportional to the amount of light plants intercept and allocate to different organs. When plants are carbon (C) limited, due to defoliation, they allocate more C preferentially to shoots to restore leaf area. In contrast, water and nitrogen (N) limitations lead to a greater allocation of C to roots. Changes in the root:shoot ratio therefore reflect changes in C and N partitioning and indicate their relative priority. A major factor that influences plant responses to stress is their ability to store and remobilise reserves to restore leaf area. Species with tap roots, like lucerne, have a large potential C and N storage capacity that is utilised seasonally for storage and remobilisation. This has been used to develop seasonally based grazing management rules. Similarly, recommendations to graze perennial ryegrass at the 2- or 3-leaf stage are based on the balance between maximizing growth rates and the need to replenish water-soluble carbohydrate reserves. However, perennial ryegrass has lower levels of perennial reserves than other grass species. This reduces its resilience to concurrent water deficits or N deficiency. Under these conditions maintaining the recommended 3-leaf grazing intervals and/or leaving higher post-grazing pasture masses are recommended to assist canopy recovery. Other grass species, such as cocksfoot and tall fescue, provide more resilience, particularly in response to water deficits.

Investigation of co-ensiling for the storage of grain stillage and Jerusalem artichoke residue from inulin extraction

Jerusalem artichoke residue (JR) was co-ensiled with grain stillage (GS) at various weight mixing ratios (JR only, 4 to 1, 2 to 1, 1.2 to 1, 1 to 1.5, 1 to 2.7, 1 to 7, and GS only) for 10, 30, and 60 d for agricultural biomass storage. Results showed that the middle level of GS to JR ratios, e.g., 1.2 to 1 and 1 to 1.5, achieved the best co-ensiling performance among all studied ratios. The water-soluble carbohydrate (WSC) contents were significantly higher than those of the other treatments (p < 0.05), and the lignocellulose contents were significantly lower than those of other treatments (p < 0.05). The silages ensiled at the above-mentioned ratios had a higher feed value and biodegradation potential than other ratios. Lactobacillus was the dominant bacterial species during the ensiling process, and its relative abundance was significantly correlated with the content of different components, e.g., WSC, crude protein, and starch, as well as fermentation characteristics. Fungal species, e.g., Kluyveromyces and Monascus were also observed, and the relative abundance of which was positively correlated with different nutritional components. In conclusion, GS and JR can be successfully stored via co-ensiling.

Estimation of Nitrogen Use Efficiency for Ryegrass-Fed Dairy Cows: Model Development Using Diet- and Animal-Based Proxy Measures

This study aimed to identify suitable predictors of nitrogen (N) use efficiency (NUE; milk N/N intake) for cows that differed in breeds and were fed with ryegrass pasture, using existing data from the scientific literature. Data from 16 studies were used to develop models based on the relationships between NUE and dietary and animal-based factors. Data from a further 10 studies were used for model validation. Milk urea N (MUN) and dietary water-soluble carbohydrate-to-crudeprotein ratio (WSC/CP) were the best and most practical animal- and diet-based proxies to predict NUE. The results indicate that it might be necessary to adopt separate models for different breeds when using WSC/CP to predict NUE but not when using MUN.

The Quality, Intake, and Digestibility of Virginia Fanpetals (Sida hermaphrodita L. Rusby) Silage Produced under Different Technologies and Its Effect on the Performance of Young Cattle

Different harvesting and preservation methods of Virginia fanpetals herbage were evaluated, based on the chemical composition and digestible organic matter (OM) content (D-value) of silage fed to adult sheep, the intake and digestibility of silage, and the performance of young cattle. The following harvesting methods were compared: direct-cut harvesting with a precision-cut forage harvester (DC), harvesting after field wilting with a precision-cut forage harvester (WC) or a round baler (WRB). The silage was fed for 81 days to 24 Polish Holstein Friesian (HF) bulls, as the sole forage supplemented with 3.0 kg of concentrate/head/day. Harvesting methods affected the density (p < 0.001) and water-soluble carbohydrate (WSC) content (p = 0.047). Differences were found among the groups in the digestibility coefficients of OM (DC-73.7, WC-78.9, WRB-79.9%) (p = 0.007), and crude protein (CP) (69.8%, 77.1%, 78.5%, respectively) (p < 0.001). Dry matter intake (DMI) reached 8.38 kg (DC), 8.74 kg (WC) and 7.21 kg (WRB). Live weight gain (LWG) differed (p < 0.001) among groups (0.939, 1.033, 0.813 kg/day, respectively). The feed conversion ratio (FCR) tended to improve in WC (8.66 kg DMI/kg LWG) (p = 0.08). The highest-quality silage was produced in group WC, and it could be successfully fed to growing bulls as the sole forage.

Decreasing Defoliation Frequency Enhances Bromus valdivianus Phil. Growth under Low Soil Water Levels and Interspecific Competition

Bromus valdivianus Phil. (Bv) is a water stress-tolerant species, but its competitiveness in a diverse pasture may depend on defoliation management and soil moisture levels. This glasshouse study examined the effect of three defoliation frequencies, based on accumulated growing degree days (AGDD) (250, 500, and 1000 AGDD), and two soil water levels (80–85% of field capacity (FC) and 20–25% FC) on Bv growth as monoculture and as a mixture with Lolium perenne L. (Lp). The treatments were applied in a completely randomised block design with four blocks. The above-ground biomass of Bv was lower in the mixture than in the monoculture (p ≤ 0.001). The Bv plants in the mixture defoliated more infrequently (1000 AGDD) showed an increase in root biomass under 20–25% FC compared to 80–85% FC, with no differences measured between soil water levels in the monoculture. Total root length was highest in the mixture with the combination of infrequent defoliation and 20–25% FC. Conversely, frequent defoliation treatments resulted in reduced water-soluble carbohydrate reserves in the tiller bases of plants (p ≤ 0.001), as they allocated assimilates mainly to foliage growth. These results provide evidence that B. valdivianus can increase its competitiveness relative to Lp through the enhancement of the root growth and the energy reserve in the tiller base under drought conditions and infrequent defoliation in a mixture.

An Overview on the Factors Affecting Water-soluble Carbohydrates Concentration during Ensiling of Silage

Water-soluble carbohydrates (WSC) concentration during the ensiling process is influenced by both controllable and uncontrollable factors such as temperature, moisture level, fertilizers, additives nutrients, and time of ensiling of silage. The WSC contents may vary among the different fodder and forage species. The ensiling temperature has a limiting impact on water-soluble carbohydrates and their concentration decrease with increasing temperature. Crops should be harvested at optimum moisture and dry matter level to reach the required concentration of water-soluble carbohydrates to produce organic acids. Water-soluble carbohydrate concentration decreased with the crop's maturity due to the accumulation of carbohydrates in the grains. The evening cut has more concentration of WSC than that of the morning cut due to the photosynthesis process. The contents of WSC can be increased by using different kinds of additives during the ensiling process. Ensiling time has not much influence on the water-soluble carbohydrates. To understand these factors, we have a detailed review of the factors affecting the WSC of silage.

The use of an herbicide as a tool to increase livestock consumption of medusahead (Taeniatherum caput-medusae)

Medusahead [Taeniatherum caput-medusae (L.) Nevski] is an invasive annual grass spreading into rangelands throughout the western United States. We tested cattle (Bos taurus L.) utilization of T. caput-medusae following treatment with glyphosate in two forms of its salt (potassium salt and isopropylamine salt) at three different rates of application; low (236 g ae ha-1), medium (394 g ae ha-1), and high rate (788 g ae ha-1) in eastern Washington. The herbicide was applied on April 26, 2016. A second location, northern Utah, was treated with glyphosate in the form of its isopropylamine salt at the high rate. The herbicide was applied on June 5, 2019. Cattle were allowed to start grazing T. caput-medusae 15-d after glyphosate treatment and cattle had unlimited access to the glyphosate treated plots for over 85 days. The greatest utilization of T. caput-medusae occurred at the highest glyphosate application rate (P < 0.05), in Washington, with no difference between forms of glyphosate salt. Cattle also consumed T. caput-medusae at the Utah site (P < 0.05). Glyphosate treatment preserved the water-soluble carbohydrate content of T. caput-medusae at levels greater than the non-treated controls (P < 0.05) at both locations. The glyphosate treatment assisted in the increased utilization of T. caput-medusae by cattle and is a viable option for the reduction of T. caput-medusae while increasing the forage value of the weed.

Leaf Physiological and Water Soluble Carbohydrate Content Responses to Trinexapac-ethyl Application of Sports Turf Grasses Exposed to Water Stress

Water stress causes alterations in physiological and metabolic processes in plants and is considered the primary environmental factor affecting the management of sports turf grass species.This glasshouse experiment was conducted to investigate the effect of trinexapac-ethyl (TE) on canopy net photosynthesis (Pn), cell membrane stability (CMS), turf quality (TQ) and water soluble carbohydrate (WSC) accumulation responses of sports turf cultivars [Cv] (100% fescue, Rootzone and Arena sports) subjected to water stress. Commercially obtained sods of turf plants were treated with 2 L/ ha TE and then exposed 7 days after to water stress. The treatments were: (i) water untreated, (ii) water TE-treated, (iii) water stress untreated; and (iv) water stress TE-treated and the experiment was a randomized complete block design with four replicates. Results showed that specifically in Cv. Rootzone, Pn was 50% higher for well water TE treated plants compared to the other treatments during the second and third week of the study. Similarly, at 14 days after application, the effect TE resulted to 35% and 50% reduction in cell membrane leakages respectively in well water and water stressed TE-treated Cv. Rootzone plants and this was statistically significant (P=0.05) different from the untreated plants. On a scale of 1-9, all turf types recorded TQ rating of ≥8 at the start of the experiment. By the fourth week of the study, it was observed that all water stress untreated plants had mean TQ (5.75) ratings lower than the minimum acceptable TQ (6). WSC content of well-watered TE-untreated plants was maintained below 60 mg/g DW throughout the study regardless of turf type. After 28 day of water stress duration, the WSC contents obtained in water stress TE-treated plants were 41%, 43% and 50% higher for Cv. Rootzone, 100% fescue and Cv. Arena sports, respectively , than in well water untreated plants. Summer preconditioning of plants with TE can be a possible management tool in alleviating the detrimental impacts of water stress in sport turf species.

Evaluation of sainfoin accessions exposed to powdery mildew disease at four locations in Iran

In order to evaluate resistance of sainfoin (Onobrychis viciifolia) to powdery mildew, seeds of 19 accessions were collected from different parts of Iran and sown at 4 locations, i.e. Kheirabad, Khoramabad, Semirom and Tabriz, in 2014. Accessions were evaluated for powdery mildew severity index (DSI), forage dry matter yield (DM), dry matter digestibility (DMD) and crude protein (CP) and water soluble carbohydrate (WSC) concentrations over 4 years. Based on Duncan’s test, accessions 15353 and 3001 showed disease severity index lower than 25% and were nominated as resistant to powdery mildew. Accessions Oshnavieh and Polycross were considered semi-resistant due to their DSI ranging from 25 to 50%. Other accessions were considered susceptible because their DSI was higher than 50%. The resistant accessions (15353 and 3001) with average yields of 3,341 and 3,304 kg DM/ha were ranked as having high DM production, in addition to displaying high DMD plus high CP and WSC concentrations. Severity of powdery mildew infection was linked negatively with all 3 quality traits, i.e. DMD and CP and WSC concentrations. According to Eberhart/Russell regression results, stability of accessions 3001 and 15353 for DSI and DM yield was confirmed across 4 locations. We recommend the use of accessions 3001 and 15353 in future breeding programs to increase resistance to powdery mildew, while at least maintaining yield and quality attributes. Evaluation of other sources of sainfoin germplasm should continue to identify further resistant accessions.