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This study aimed to evaluate forage mass, morphological, and chemical composition of diploids and tetraploids Italian ryegrass cultivars in hydromorphic soil. Eight ryegrass cultivars were evaluated in a two-years completely randomised trial with four plots per cultivar. Forage production was recorded, and samples were collected to evaluate morphological and chemical composition. The contrasts methodology was used to verify differences between diploid and tetraploid cultivars. Compared to tetraploids, the diploids had the greatest number of cuts and the largest accumulation of forage in the second year, highlighting the better adaptation of cultivars in hydromorphic soils. Tetraploid ryegrass increased leaves and reduced stem and inflorescence proportion relative to diploid ryegrass. Tetraploid cultivars had lower DM, organic matter, and acid detergent fibre content than diploid cultivars. However, there was no significant difference between cultivars associated with their ploidy for the neutral detergent fibre and estimated total digestible nutrients. Additionally, only in the second year, tetraploid had lower crude protein content than diploid ones. Tetraploid ryegrass showed be less tolerant to periods of water stress due to flooding, characteristic of hydromorphic soils, resulting in less forage production than diploid ryegrass. [ABSTRACT FROM AUTHOR]

Combining several cultivars within species in seed mixtures is often advocated as a means for improving crop or pasture performance. Herbage accumulation (HA) of perennial ryegrass-white clover pastures sown with a single cultivar representing different functional types of perennial ryegrass was compared with the HA of cultivar mixtures over three years in two contrasting environments (Waikato, dryland; Canterbury, irrigated) under dairy cattle grazing. Functional types were: mid-season flowering diploid, late-season diploid, and late-season tetraploid. Mixture treatments (n = 4 at each site) included all binary combinations plus the three-way combination. Mixture HA and the mean HA of the constituent cultivars did not differ for any of the mixture combinations in either environment, apart from winter in Waikato where the mid-diploid plus tetraploid mix out-yielded the mean of the individual cultivars and tended to increase total annual HA. The total annual HA of the mixtures was between 1.0 and 2.3 t DM/ha/year less than the HA of the highest-yielding individual cultivar included in the mixture in six of the eight mixture-environment combinations. While some benefits of mixtures for controlling grazing outcomes were observed, sowing individual high-performing cultivars is a better overall strategy than mixing cultivars to cover a spectrum of traits. [ABSTRACT FROM AUTHOR]

Herbage accumulation (HA) data from four sites were combined to (1) address the hypothesis that adjustments to the New Zealand Forage Value Index to account for grass-clover interactions are not required and (2) explore the main effects of clover and nitrogen (N) fertiliser treatments on pasture productivity. In summer and autumn, pastures based on mid-season heading ryegrass cultivars consistently supported a greater clover content than pastures based on late heading cultivars. However, the clover ×  cultivar interaction was significant in only 2 of 17 HA data sets available for analysis. Thus, the hypothesis is supported. Compared with ryegrass monocultures, mixtures yielded an additional 2.4 (in the Low-N treatment) and 1.2 (High-N treatment) t DM/ha/year. Apparent N transfer from clover to grass was 79 (Low N) and 27 (High N) kg N/ha/year, derived from estimated N fixation efficiencies of 66 (Low N) and 50 (High N) kg N/t clover DM grown. [ABSTRACT FROM AUTHOR]

Concentrations of boron, cobalt, copper, iron, manganese, molybdenum, selenium and zinc were measured in eight perennial ryegrass cultivars grown at four sites in New Zealand (Waikato, Manawatu, Canterbury and Southland). Herbage samples were collected from pure ryegrass plots, grown with two nitrogen fertiliser rates, with three sites sampled in autumn (April/May 2013) and all four sites in spring (October/November 2013). There were significant differences among the cultivars for most of the elements, but consistent patterns were not obvious due to interactions involving site, season and nitrogen fertiliser treatment. It is concluded that breeding ryegrass for variation in micronutrient concentrations is unlikely to be productive. [ABSTRACT FROM AUTHOR]

Concentrations of nitrogen, phosphorus, potassium, calcium, magnesium, sulphur and sodium were measured in eight perennial ryegrass cultivars grown at four sites in New Zealand (Waikato, Manawatu, Canterbury and Southland). For the macronutrient analyses, herbage samples were collected from pure ryegrass plots, grown with two nitrogen fertiliser rates, with three sites sampled in autumn (April/May) and all four sites in spring (October/November) of 2013. There were significant differences among the cultivars for all elements except potassium, extending the results of earlier research to contemporary commercial cultivars. It is suggested that breeding ryegrass for lowered shoot phosphorus concentration should be prioritised because of the economic and environmental benefits to be gained from farming with reduced phosphate fertiliser requirements. [ABSTRACT FROM AUTHOR]

This paper describes how the core treatments in the national experimental design (all combinations of with/without clover and high/low nitrogen (N)) were implemented at an irrigated Canterbury site and monitored for three years. There was a consistent N × clover interaction, caused mainly by substantially lower yields in the Low N without clover treatment compared with all other treatments. At the phenotypic contrast level, the main effect of perennial ryegrass heading date on white clover content was significant in four of the nine seasonal data sets available: on these occasions, mixtures based on mid-season heading cultivars had higher clover content than later season-heading cultivars. However, this difference was not sufficient to cause any clover × cultivar interactions in herbage accumulation. Hence, the hypothesis that relative yield rankings of ryegrass cultivars do not differ when ryegrass is grown in monoculture or in mixture with white clover is supported. [ABSTRACT FROM AUTHOR]

The implementation and monitoring of the treatments in the core experiment (eight perennial ryegrass cultivars grown under four combinations of plus/minus clover and high/low nitrogen (N)) at a dryland Waikato site is described. The N x clover interaction was significant in 10 of the 17 seasonal or total annual herbage accumulation (HA) data sets available, caused by substantially lower annual HA in the low N minus clover treatment compared with all other treatments. Five significant scaling-type clover × cultivar interactions in HA were evident. In all cases, HA was greater in plus clover than minus clover treatments, but more so for some cultivars than others. However, the interactions were not consistent across seasons, and different cultivars or phenotypic contrast groups were involved in many cases. The hypothesis that relative HA rankings of ryegrass cultivars do not differ when ryegrass is grown in monoculture versus mixtures with white clover is supported. [ABSTRACT FROM AUTHOR]

This experiment, implemented at a Southland site representative of the lower South Island, New Zealand, and monitored for three full years from 2012/2013 to 2015/2016, was one of four throughout New Zealand that investigated the yield and nutritive value rankings of perennial ryegrass cultivars sown with or without white clover and with high (225 kg N/ha/annum) or low (50 kg N/ha/annum) application rates of nitrogen fertiliser. High inputs of nitrogen (N) fertiliser increased annual total dry matter (DM) yields and seasonal yield in 12 out of 18 measurement occasions. Adding white clover increased both annual dry matter yield and seasonal yield in 7 out of 18 measurement occasions. An interaction between clover and N input occurred on 10 occasions. Over time, the low N minus clover treatment became progressively lower yielding compared with the other three treatments. Ryegrass cultivar by clover interactions occurred in the latter half of the experiment. When analysed using ryegrass characteristics, early- and late-heading ryegrass cultivars produced similar yields when sown without clover, but late-heading ryegrass cultivars had a higher yield than early-heading pastures when sown with white clover (P < .001). Tetraploid ryegrasses had lower yields than diploid ryegrasses when sown without clover (P = .001). This difference was reduced when white clover was included. There was no significant interaction with ryegrass morphology when sown with white clover, as dense ryegrass cultivars always had a higher yield than open ryegrass cultivars (P = .005). Interactions occurred between N input levels and ryegrass cultivar. These occurred in early spring or late spring of each year. Analysis by ryegrass characteristics identified consistent interactions. Ryegrass cultivars with a late-heading date were higher yielding than early-heading cultivars at low N inputs (P = .029), but they were not different at high N inputs. Diploid and tetraploid ryegrass cultivars were similar with low N inputs, but diploid cultivars out-yielded tetraploid cultivars at high N inputs (P = .005). Significant interactions between N inputs and white clover addition affected herbage nutritive value but this did not extend to consistent interactions with ryegrass cultivar. Invertebrate pest numbers were generally low and unlikely to have influenced clover/ryegrass interactions or cultivar ranking. Results from this site suggest that ranking of ryegrass cultivars needs to account for both the inclusion of clover and variation in N fertiliser input. [ABSTRACT FROM AUTHOR]

The development of economic indexing systems for ranking cultivars of forage species requires new knowledge of factors that may influence the scaling of agronomic data collected in controlled, small-plot evaluation trials to whole farm systems. In the case of perennial ryegrass indexing, one such knowledge gap is the effect of growing clover with ryegrass on the relative rankings of different ryegrass cultivars. The objective of the investigation reported in this series was to test whether the relative yield rankings of perennial ryegrass (Lolium perenne L.) cultivars representing the range in phenotypes now available to New Zealand farmers as a result of recent breeding differed when those cultivars were grown in monocultures (as per standard protocols for cultivar yield trialling systems such as the National Forage Variety Trials) versus mixtures of grass and clover. This paper presents the rationale for the investigation by reviewing developments in perennial ryegrass breeding and evaluation in the context of grass-clover relationships in grazed pasture systems. The papers that follow report results from a multi-year, multi-site investigation comparing the yield, nutritive value and other productivity-related variables of eight perennial ryegrass cultivars grown with or without white clover (monoculture versus mixture respectively) at two levels of nitrogen fertiliser. Key considerations in the design of the experiment on which the investigation was based are discussed. [ABSTRACT FROM AUTHOR]

Perennial ryegrass (Lolium perenne L.) can be sown as a mixture of cultivars, but different eco-physiological mechanisms among cultivars can cause the cultivar proportions to change over time. The objectives of this work were to differentiate the cultivars 'Barnhem', 'Barmaco', 'Barlet' and 'Mara', and to identify their proportions in mixture. Two seed-lots of each cultivar were characterised using one simple sequence repeat (SSR) and two inter-SSR (ISSR) markers. Simulated mixtures based on random sub-samples from monocultures of each cultivar showed that individuals could be correctly allocated to their respective seed-lot and cultivar with 78-87% accuracy using discriminant analysis. 100 BG34 plants were collected from three dairy pastures in Ohio, USA and their SSR/ISSR profiles were compared with the reference populations. One pasture had a similar cultivar proportion as the original sown mixture. Two pastures had increased proportions of 'Mara' and 'Barmaco' and decreases of 'Barlet' or 'Barnhem', depending on the pasture. [ABSTRACT FROM AUTHOR]

Agronomic trials at cool (Gore) and warm (Palmerston North) temperate sites in New Zealand tested ten United Kingdom-bred (six diploids, four tetraploids) and two New Zealand-bred diploid ('Bronsyn', 'Impact') perennial and long-term hybrid ryegrasses (Lolium perenne, L. boucheanum) over two trial periods. Dry matter (DM) yields and persistence were better at the cool site but differential expression among cultivars for water-soluble carbohydrates (WSC) and yields was small compared with the warm site. The tetraploid cultivars generally had the highest concentrations of WSC but also on occasions had higher levels of crown rust, moderate DM yields and poorer persistence compared with diploids. Two of the tetraploid cultivars will be of value for their high WSC and good agronomic performance at the cool site. Some of the diploid UK cultivars expressed higher WSC and had similar or higher annual DM yields than some of the NZ-bred cultivars, and had high levels of resistance to crown rust. Overall, differences among cultivars in expression of WSC were small. Some differences occurred for seasonal DM yields with some UK cultivars having lower winter yields. [ABSTRACT FROM AUTHOR]

To gain information about how widening of the row distance influences seed yields in first-year perennial ryegrass, experiments with four row distances in three types of perennial ryegrass were conducted at the University of Aarhus, Faculty of Agricultural Sciences. Perennial ryegrass was undersown at 12-, 24-, 36-, or 48-cm row distance in a cover crop of spring barley. The seeding rate in perennial ryegrass was 6 kg seeds ha-1 regardless of row distance. Although increasing the row distance from 12 to 48 cm had a negative effect on the yield component number of reproductive tillers, the yield was not affected in the first-year seed production in three perennial ryegrass cultivars. Regardless of row distance the seed rate was 6 kg ha-1 and hence in-row plant density in autumn and spring was higher at 48 compared with 12 cm; however, in all three cultivars the highest number of reproductive tillers was recorded at 12-cm row distance. Row distance affected seed yields of only the diploid amenity cultivar 'Allegro', where a row distance of 48 cm reduced the seed yield compared with 12- and 24-cm row distance. When data from the three cultivars were merged there was a positive correlation between the seed yield and seed weight (r=0.72***), whereas the correlation between seed yield and the number of reproductive tillers was negatively correlated (r= - 0.49***). This may reflect choice of cultivars in the experiment with the tetraploid forage cultivar 'Tivoli' having the lowest number of reproductive tillers, highest seed weight, and highest seed yield, and the diploid amenity cultivar 'Allegro' having the highest number of reproductive tillers, lowest seed weight, and the lowest seed yield. When the three cultivars were merged, there was a positive and highly significant correlation between seed weight and seed yield (r=0.72***). In contrast, there was no correlation between seed weight and seed yield when data were analysed for the individual cultivars. This suggests a cultivar-dependent relationship between seed weight and seed yield and furthermore between number of reproductive tillers and seed yield. [ABSTRACT FROM AUTHOR]

Even though the effect of poultry litter application on runoff nutrient concentrations has been thoroughly evaluated, the timing of broiler litter application and estimated runoff nutrient dynamics are not well documented. The objectives of this study were to evaluate how time to rainfall and repeated rain events affect nutrient concentrations and dynamics in runoff from a Ruston sandy loam (fine, mixed active, thermic Aquic Hapludults) soil established with Bermuda grass (Cynodon dactylon L.). Air-dried soil was packed into runoff boxes (144 cm long, 20 cm wide, and 10 cm deep) to a bulk density of 1.30 g cm³. Hybrid Bermuda grass was established by plugging (26 plugs per box). Broiler litter was broadcast at the rate of 9 Mg ha-1. Simulated rainfall (27 mm h-1) was applied until 15 mm of runoff was collected at 0, 3, 6, and 9 d after broiler litter application. Also, 8 successive rainfall events were applied at 3-d intervals to the soil incubated for 9-d with broiler litter and commercial fertilizer and runoff was collected for 15 mm for each rain event. Increasing time between litter application and rainfall event from 0 to 9 d reduced runoff of total N, NH4-N and NO3-N by 50, 64, and 31%, respectively. Total P and dissolved P concentrations in runoff de- creased to 35 and 43% of initial time of application values (0 d), respectively. Runoff N, P, K, Ca, Mg, Cu, and Zn concentrations decreased with successive rain events and approached the ones in unfertilized soil. Avoiding litter applications during periods of possible high intensity rainfall reduces the potential environmental hazard. [ABSTRACT FROM AUTHOR]

Long-term poultry litter application to crop and pasture lands may result in the buildup of nutrients, particularly phosphorus (P) in the soil. Poultry producers use poultry litter in place of chemical fertilizers to grow crops or forages for grazing and hay production. Cool-season annual ryegrass (Lolium multiflorum) and warm-season crabgrass (Digitaria ciliaris) are annual forages commonly grown in the southeastern region of USA. The combination of two forages gives year-round pasture for a forage-livestock system. A study was initiated to evaluate the P uptake efficiency of five ryegrass cultivars (Marshall, Rio, Jackson, TAM 90, and Gulf) grown during the winter and spring followed by the annual crabgrass variety Red River during summer. The experiment was conducted during the 2000 and 2001 growing seasons in Mize Mississippi on a highly P enriched Ruston silt loam soil. The ryegrass was grazed during winter then harvested once in early June. Cultivar Rio produced the greatest dry matter (DM) in both growing seasons. In 2001, due to optimum soil moisture conditions, cultivars Gulf and TAM 90 produced more DM than 2000, an extremely dry year. In 2001 crabgrass planted after TAM 90 produced significantly greater DM (7565 kg ha−1) than crabgrass following the other ryegrass cultivars. Cultivar Marshall was the most effective in removing P from soil in 2000 (7.38 kg ha−1), while Rio was superior in 2001 (8.73 kg ha−1). In general, crabgrass was more effective in P removal than ryegrass cultivars tested. Therefore, the combination of ryegrass followed by crabgrass may provide an effective forage-livestock management system in the southeastern states. [ABSTRACT FROM AUTHOR]

The article discusses a breeding project aimed at producing ryegrass cultivars with branched inflorescences in New Zealand. The first cultivar produced was the GA143, which achieved about double the number of florets compared with unbranched cultivars. It is said that the breeding project was continued by transferring the branched character into annual and hybrid ryegrass which resulted to three germplasms including GA189 perennial ryegrass, GN190 hybrid ryegrass and GB191 Italian ryegrass. The characteristics of each germplasm are described.