Effects of Mixture Sowing on Forage Yield and Interspecific Competition of Alfalfa and Orchard Grass

[ Objective] To explore the mixture sowing effects and optimal mixture ratio of alfalfa and orchard grass. [ Method] The alfalfa and orchard grass were sowed at different ratios （1 ： 0, 3： 1, 1 ： 1, 1 ： 3 and 0：1 ）. They were grouped and named as CK1, A1, A2, A3 and CK2., respectively. The forage yield, relative yield total （RYT） and the competition rate （CR） of alfalfa and orchard grass in each group were determined, respectively. [ Result] In the A3 treatment group, the total forage yield was the highest （4 827.67 kg/hm2） and significantly different from that of other treatment groups （ P 〈 0.01 ）. In every treatment group, the RYT was higher than 1, and the alfalfa was more competitive than the orchard grass in the mixed-seeding pasture. [ Conclusion] Our studies may provide a basis for the establishment of high yield and high quality artificial mixture pasture.

Effects of Meteorological Factors on Overwintering Ability,Yield and Quality of Forage Rape

In order to investigate the effects of meteorological factors on rape overwintering ability,forage yield and quality of rape in the North China plain,Brassia campestris L.and Brassica napus L.were used in this study.The results showed that compared with the B.napus L.varieties,the growth period of B.campestris L.was shortened by 10-15 d,the overwintering rate(WR)increased by 50.6%,and the density after winter(PD)increased by 41.5%.The fresh forage yield(FFY)and dry forage yield(DFY)of the B.campestris L.type significantly increased by 40.9%and 38.1%compared with the B.napus L.type.,respectively,while the forage quality of the B.napus L.type rape was significantly better than that of the B.campestris L.type.Compared with the B.campestris L.type,the crude protein(CP),fat,ash and total fatty acid(TFA)contents of the B.napus L.type of rape increased by 27.6%,42.9%,23.9%and 52.3%,respectively,and the milk productivity(HM),relative forage value(RFV)and relative forage quality(RFQ)increased by 14.0%,16.2%and 42.1%,respectively.The light and heat resources before wintering increased the WR and PD(P<0.05),and were positively correlated with FFY and DFY(P>0.05),and lower temperature during the wintering period led to lower WR(P<0.01).The light and heat resources during the overwintering period and after regreening were negatively correlated with FFY and DFY(P>0.05).The contents of CP,fat and TFA of rape had an extremely significant negative correlation with the temperature and sunshine hours before wintering,but an extremely significant positive correlation with the temperature during the wintering period and after regreening,as well as the sunshine hours and rainfall during the wintering period;and HM had an extremely significant positive correlation with the temperature,sunshine hours and rainfall during the wintering period,while RFV and RFQ were only extremely significantly positively correlated with the maximum temperature and rainfall.In summary,in the North China Plain,for autumn sowing rape,the B.campestris L.type can be selected to improve the wintering rate,and the B.napus L.type should be the main choice to improve the forage quality of rape.Therefore,the B.napus L.variety HYZ62 can be selected for autumn sowing in the North China Plain.

Effect of Salinity Stress on Growth and Yield of Forage Genotypes

Salinity is the major limiting factor for forage productivity in southwestern coastal region of Bangladesh. Some introduced forage cultivars have been shown promising adaptability in saline conditions. The objective of this study was to assess the productivity and measure the agronomic characteristics of several introduced grass species with different created soil salinity levels. This study was conducted at the net house of Dr. Purnendu Gain Field Laboratory, Agrotechnology Discipline, and Khulna University during the period from December 2017 to February 2018. The experiment was laid out in a factorial randomized complete block design with seven replications. The experiment consisted of two factor viz. soil salinity levels (S1 = 0.48, S2 = 5.8, S3 = 7.9, S4 = 9.4, S5 = 15 d·Sm−1) and thirteen forage genotypes. Salinity levels and forage genotypes significantly (p < 0.05) influence all the growth parameters and biomass yield. The growth parameters and yield gradually decreased with the advance of soil salinity level. The tallest plant height (109.85 cm) was found in S1 at 90 DAS while the shortest plant (24.53 cm) was obtained in S5 at 90 DAS. Soil salinity had a significant difference (p < 0.001) on plant height at 90 DAS. The highest numbers of tillers (3.36) were found in S1, whereas the lowest (0.48) was in S5 at 75 DAS. Soil salinity had a significant difference (p < 0.001) on Number of tillers at 75 DAS. The highest biomass wt. (29.14 g) was found in S1, while the lowest biomass wt. (3.52 g) was obtained in S5 at 60 DAS. Soil salinity had a significant difference (p < 0.001) on biomass wt. at 60 DAS. The highest dry matter% (DM%) (21.24%) was found in S4, while the lowest DM (18.74%) was obtained in S1 at 60 DAS. Soil salinity had a significant difference (p < 0.001) on dry matter% (DM%) wt. at 90 DAS. The tallest plant height (81.93 cm) was found in Pakchong, while the shortest plant (20.13 cm) was obtained in Endropogan at 60DAS. Soil salinity had a significant difference (p < 0.001) on plant height at 60 DAS. The highest numbers of tillers (3.07) were also found in Napier-3, whereas the lowest (0.80) was in H. Jaumbo at 75 DAS (S1 + S2 + S3 + S4 + S5). Soil salinity had a significant difference (p < 0.001) on Number of tillers at 75 DAS. The highest biomass wt. (38.60 g) was found in Pakchong, while the lowest biomass wt. (4.49 g) was obtained in Oats at 60 DAS. Soil salinity had a significant difference (p < 0.001) on biomass wt. at 60 DAS (S1 + S2 + S3 + S4 + S5). The highest (DM%) was found in Endropogan (24.68%), while the lowest DM (18.37%) was obtained Spelindida. Soil salinity had a significant difference (p < 0.001) on DM at 90 DAS. It can be concluded that Pakchong appears to be highly salt tolerant.

Studies on Biomass Yield, Morphological Characteristics and Nutritive Quality of Napier Cultivars under Two Different Geo-Topographic Conditions of Bangladesh

The aim of the present study was to evaluate the performance of Napier cultivars in terms of forage yield, plant morphology and nutrient contents under two different agro-ecology and geo-topographic conditions. Three Napier cultivars being conserved by Bangladesh Livestock Research Institute (BLRI), namely-BLRI-Napier 1, (BN-1), BLRI-Napier 3 (BN-3) and Merkeron (BN-5) were selected to cultivate in severe drought prone areas (called Barind) and non-drought area at Savar (Modhupur terrace). Stem cuttings were planted in rows apart from 70 cm and 35cm spacing between plants. Data of 6 consecutive harvests from a period of approximately one year were collected and analyzed statistically by “R” software. The results showed that cultivar and location had a significant (P < 0.001) effect on biomass yield, plant height and leaf-stem ratio (LSR), while number of tillers were significantly varied with locations. BN-3 yielded the highest biomass (33.32 t/ha/harvest) at non-drought location (42.98 t/ha/harvest). The highest plant height was obtained in BN-1 (171.2 cm) at non-drought location (174.6 cm). Number of tillers per hill ranged from 25.4 to 26.3 among cultivars (P > 0.05) and the highest tillers were found at non-drought location (28.1 no). The best LSR was estimated from BN-5 (0.86) at drought location (0.95). The proximate analysis showed that CP, ADF and NDF in whole plant were varied significantly (P < 0.001), being the highest contents in BN-1 (10.69%, 46.20% and 54.58%, respectively). On the other hand, DM and ash contents did not differ significantly (P > 0.05) among cultivars which ranged from 15.80% to 17.13% and 13.10% to 14.58%, respectively. The highest CP content in whole plant was obtained at non-drought location (11.89%), while the lowest ash (10.57%) and NDF (52.71%) contents were obtained at the same location. The highest CP contents in leaf were found at non-drought (15.03%) and the lowest ash (9.86%) at the same location. The highest CP contents (5.90%) in stem were found at non-drought location, while the lowest ash (11.28%) and NDF (54.59%) contents were obtained at the same location. Finally, the experiment reveals the superiority in biomass yield and nutritional quality (in terms of CP content) with the ranking orders of BN-3 > BN-1 > BN-5 and BN-1 > BN-3 > BN-5. Therefore, it may be concluded that BN-1, BN-3, and BN-5 cultivars were well adapted in both drought and non-drought conditions, although performance showed better in later conditions. However, in terms of forage yield and overall nutrient composition, the performance of BN-3 was the best irrespective of locations.

The Yield and Water Use Efficiency to First Cutting Date of Siberian Wildrye in North China

A field experiment study was conducted in Bashang Plateau in North China in 2008 to determine the effect of three first cutting dates on the growth and water use efficiency （WUE） of Siberian wildrye （Elymus sibiricus L.） in the agropastoral ecotone of North China （APENC）. The experiment was conducted in a split plot design with three replications with water supply regime as the main plot treatment and first cutting date as the subplot treatment. Two water supply regimes were used, which included rain-fed treatment as control （CK） and a single irrigation and straw mulch treatment （W）. Three first cutting date treatments were conducted at early heading stage on July 1 （E）, at late heading stage on July 12 （L）, and at flowering stage on July 27 （F）, respectively. The results showed that the forage yield and WUE were the lowest at early heading stage harvest, while the highest at flowering stage either in CK or W treatment. Under combined CK and W treatments, average forage yields of the F subplots were 2 900 and 6 703 kg ha-~, and the values of WUE were 0.82 and 2.28 kg m-3, respectively. Under the CK treatment, forage yields of the E and L subplots were 43.8 and 41.9% lower than the F subplots, and their values of WUE were 46.2 and 50.3% lower than F, respectively. Under the W treatment, the forage yields of the E and L subplots were 74.9 and 61.6% lower, and their values of WUE were 78.1 and 63.3% lower, respectively, as compared with F subplots. Therefore, earlier first cutting did not increase the regrowth of Siberian wildrye and improve the mismatch between rainy season and the period of high growth potential of the grass in the semiarid APENC.

Validation of a Technique for Estimating Alfalfa (Medicago sativa) Biomass from Canopy Volume

Determining biomass production of individual alfalfa (Medicago sativa L.) plants in space planted evaluation studies is generally not feasible. Clipping plants is time consuming, expensive, and often not possible if the plants are subjected to grazing. A regression function (B′ = 0.72558 + 0.11638 × V′) was developed from spaced plants growing on rangeland in northwestern South Dakota near Buffalo to nondestructively estimate individual plant biomass (B) from canopy volume (V). However, external validation is necessary to effectively apply the model to other environments. In the summer of 2015, new data to validate the model were collected from spaced plants near Brookings, South Dakota. Canopy volume and clipped plant biomass were obtained from ten alfalfa populations varying in genetic background, growth habit, and growth stage. Fitted models for the model-building and validation data sets had similar estimated regression coefficients and attributes. Mean squared prediction errors (MSPR) were similar to or smaller than error mean square (MSE) of the model-building regression model, indicating reasonable predictive ability. Validation results indicated that the model reliably estimated biomass of plants in another environment. However, the technique should not be utilized where individual plants are not easily distinguished, such as alfalfa monocultures. Estimating biomass from canopy volume values that are extrapolations (>2.077 × 106 cm3) of the model-building data set is not recommended.

Genomic prediction of seasonal forage yield in perennial ryegrass

Background:Genomic selection has the potential to accelerate genetic gain in perennial ryegrass breeding,provided complex traits such as forage yield can be predicted with sufficient accuracy.Methods:In this study,we compared modelling approaches and feature selection strategies to evaluate the accuracy of genomic prediction models for seasonal forage yield production.Results:Overall,model selection had limited impact on predictive ability when using the full data set.For a baseline genomic best linear unbiased prediction model,the highest mean predictive accuracy was obtained for spring grazing(0.78),summer grazing(0.62)and second cut silage(0.56).In terms of feature selection strategies,using uncorrelated single-nucleotide polymorphisms(SNPs)had no impact on predictive ability,allowing for a potential decrease of the data set dimensions.With a genome-wide association study,we found a significant SNP marker for spring grazing,located in the genic region annotated as coding for an enzyme responsible for fucosylation of xyloglucans—major components of the plant cell wall.We also presented an approach to increase interpretability of genomic prediction models with the use of Gene Ontology enrichment analysis.Conclusions:Approaches for feature selection will be relevant in development of low-cost genotyping platforms in support of routine and cost-effective implementation of genomic selection.

Genotype × environment interaction patterns of dry matter yield in meadow brome, orchardgrass, tall fescue, and timothy evaluated at harsh winter sites

Background:Genotype×environment interaction(GEI)slows genetic gains and complicates selection decisions in plant breeding programs.Forage breeding program seed sales often encompass large geographic regions to which the cultivars may not be adapted.An understanding of the extent of GEI in perennial,cool-season forage grasses will facilitate improved selection decisions and end-use in areas with harsh winters.Methods:We evaluated the dry matter yield of nine meadow brome(Bromus biebersteinii Roemer&J.A.Schultes),nine orchardgrass(Dactylis glomerata L.),seven tall fescue(Lolium arundinaceum(Schreb.)Darbysh.),and 10 timothy(Phleum pratense L.)cultivars or breeding populations at seven high latitude and/or elevation locations in Canada and the United States from 2019 to 2021.Results:For each of the species,we found significant differences among the genotypes for dry matter yield across environments and found significant levels of GEI.Using site regression analysis and GGE biplot visualizations,we then characterized the extent of the interactions in each species.Except for tall fescue,there was little evidence for the broad adaptation of genotypes across locations.Conclusions:This research adds further evidence to the limitations of perennial,forage breeding programs to develop widely adapted cultivars and the need to maintain regional breeding efforts.

Trends of seasonal forage yield changes of triticale in the southern Great Plains of the United States

Background:The focus of triticale breeding in the southern Great Plains of the United States has been to increase forage yield for autumn-winter seasons when most other forage species are dormant.This study aims to estimate the trends of seasonal yield changes over time.Methods:Yield trials had been conducted in a randomized complete block design for up to two decades.Seasonal yield changes over time were estimated using linear regression analysis.Results:The analysis revealed a significant positive relation between autumn forage yield(relative to common checks)and calendar years when the trials were conducted.The estimated improvement of autumn forage yield was about 1.9%per year on medium and heavy soil at Ardmore,Oklahoma,and about 5.4%per year on light soil at Burneyville,Oklahoma.However,winter forage yield change was minimal and the spring forage yield increase was negative,although this decline was not significant.Total forage yield improvements were about 0.6%and 0.7%per year at Ardmore and Burneyville,respectively.Similar results were also observed when years of cultivars'introduction were used instead.Conclusions:The results indicate a significant gain in autumn forage yield,but a minor gain in the total forage yield due to the yield tradeoff between the autumn and spring seasons.

Mowing weakens the positive effects of nitrogen deposition on fundamental ecosystem service of grassland

Forage yield is the fundamental ecosystem service of grasslands.While the quantitative responses of forage yield to nitrogen(N)enrichment are well known,its qualitative responses remain unclear.Even less known is the relative contribution of changes in community composition to the quality of the yield at the community level.We examined the quantitative and qualitative responses of forage yield at both plant functional group and community levels with factorial treatments of N addition and mowing in a temperate steppe.Nitrogen addition significantly enhanced the community-level yield by favoring the growth of rhizomatous grass.Mowing tended to mediate the impacts of N addition on the yield.Nitrogen addition increased the concentrations of crude protein and crude fat in forage at the community level.Neither the main effects of mowing nor its interactive effects with N addition affected forage quality.The N-induced shifts in plant species composition significantly contributed to the effects of N addition on forage quality at the community level.Our results suggest that mowing wound weaken the positive effects of N deposition on the quantity but not the quality of forage yield.Changes in plant community composition are important in driving the qualitative responses of yield to N deposition.