Spring Cereals for Forage and Grain Production in a Cool Maritime Climate

Newfoundland's climate is marginal for agricultural production. The availability of locally grown cereal grain and high‐quality forage are major limitations to successful animal agriculture in this region. Here, our overall objective was to compare several spring cereal species for both annual forage and grain production in Newfoundland's cool Maritime climate. Several varieties of barley (Hordeum vulgare L.), wheat (Triticum aesitivum L.), oats (Avena sativa L.) and pea (Pisum sativum L.)–cereal mixtures for forage yield and quality, as well as grain yield and maturity, were compared in field trials on the east and west coasts in both 1999 and 2000. Barley headed earliest, yielded greatest forage dry matter, had lowest forage protein and acid detergent fibre (ADF) percentages, and had neutral detergent fibre (NDF) mean values greater than those of pea–cereal mixtures, but less than those of oats and wheat. Forage harvested from pea–cereal mixtures was similar to that of barley for yield, ADF and NDF, while P and protein percentage were much greater. Barley matured 10–15 days earlier than both wheat and oats. In general terms, all three spring cereals exhibited similar grain yield potential. Oats tillered less, but compensated by producing more kernels spike^?1. Days to maturity for cereal grains in western Newfoundland were roughly similar to those reported for the Maritime provinces of Canada. Yield and maturity results for both forage and grain production suggest that eastern Newfoundland is a unique agro‐ecoregion in North America, and agronomic recommendations specific to other regions may not be applicable in this region.     

Effect of Genotypes and Plant Maturity on Forage Quality of Certain Forage Legume Species Under Rainfed Conditions

Evaluation of plant species for animal feed requires the quantitative and qualitative comparison of different genotypes. Promising lines of annual legumes comprising seven genotypes of vetche ( Vicia spp.) and chicklings ( Lathyrus spp.) were compared for herbage quality. The content of crude protein (CP), neutral detergent fiber (NDF) and acid detergent fiber (ADF) in herbage and pods were measured at different stages of plant maturity. The proportion of the leaves to shoots (leafiness) and in vitro dry matter digestibility (IVDMD) were also determined. As plants matured IVDMD, CP and leafiness decreased and NDF and ADF increased. For all the genotypes maximum digestible dry matter (DDM) and CP yields were more or less attained at 50–100 % podding. Narbon vetch had the highest DDM. The possible uses of the different genotypes as animal feed are discussed based on the partitioning of the DDM and CP yield as plants matured.     

Evaluation of environments for preliminary testing of maize for yield and stover digestibility

Summary The identification of environments suitable for selection should enable plant breeders to test reliably a larger number of genotypes with given resources. This research was undertaken to evaluate discrimination ability (DA) and prediction ability (PA) of eight environments involving two locations. Eckartsweier (Eck) 1 and Voelkenrode (Voe); 2 yer. 1984 (84) and 1985 (85); and two harvests, silage harvest (I) and later (II). It was based on dry matter yield of plant (PDMY), ear (EDMY) and stover (SDMY) and on in vitro digestible organic matter (IVDOM), neutral detergent fibre (NDF), acid detergent fibre (ADF) and acid detergent lignin (ADL) of stover of 12 inbred lines and their 66 diallel crosses in maize (Zea mays L.). Linear regression coefficient of the performance of genotypes in an environment on that averaged across all environments and its degree of determination were used as measures of the DA and PA of environments, respectively. In hybrids, the DA of environments differed significantly for all traits except SDMY and ADL. Environment Eck851 showed better PA (0.63) than other environments for PDMY, EDMY, IVDOM, NDF, and ADF. Among the 12 two-environment combinations. EckI was a better predictor for PDMY, EDMY, IVDOM and NDF (PA0.80). The more productive environments showed better DA and PA for PDMY and FDMY than less productive ones. For IVDOM and NDF the first harvest provided better discrimination and prediction than the second harvest. In inbred lines the DA of environments differed significantly for EDMY only. In the present study, PA and DA seemed to be functions of the environments, PA was improved by combining two environments, and some environments seemed to be suitable for preliminary selection of genotypes for such diverse traits as yield and digestibility.     

Genetic variation, heritability and genetic correlations for forage quality and yield traits of Mediterranean tall fescue germplasm

Higher ruminant intake potential and in vivo digestibility as indicated by lower neutral and acid detergent fibre (NDF and ADF), respectively, and higher crude protein (CP), may be valuable targets in tall fescue breeding. Some 105 full‐sib families from a diallel cross of Mediterranean parent germplasm were grown in a heated greenhouse simulating the temperature pattern of a Mediterranean environment, to estimate genetic parameters for NDF, ADF, CP and dry matter (DM) yield in one autumn and one winter harvest. Family x harvest interaction was large for NDF and ADF, moderate for CP and absent for DM yield. Additive genetic variance was mostly larger than specific genetic variance, and tended to be small for quality traits and large for DM yield. Narrow‐sense heritability was low for CP and ADF in autumn and moderate to fairly high in the remaining cases. Predicted gains per selection cycle never exceeded 5% for quality traits while being greater than 10% for DM yield. An inverse genetic correlation between DM yield and any quality trait emerged in the presence of sizeable genetic variation.     

Near infrared reflectance spectroscopy analysis of digestibility traits of maize stover

Summary Near infrared reflectance spectroscopy (NIRS) is emerging as a potentially useful tool in breeding plants for quality traits. Information is lacking, however, on its use in forage maize (Zea mays L.). The objectives of the present investigation were to evaluate the prediction of digestibility traits of maize stover using NIRS technique and to study the effect of laboratory (Lab) and NIRS assays on the estimates of variation and covariation. Twelve inbred lines, 66 diallel crosses among them and eight hybrid checks were evaluated at silage and grain harvests for 2 years at two agro-climatically diverse locations in the Federal Republic of Germany. Standard methods were used for Lab analysis of in vitro digestible organic matter (IVDOM), neutral detergent fibre (NDF), acid detergent fibre (ADF) and acid detergent lignin (ADL). In NIRS evaluation, calibration equations were developed by modified stepwise regression. The standard error of calibration was 2.5, 1.7, 1.4 and 0.4 for IVDOM, NDF, ADF and ADL, respectively. The coefficient of multiple determination was high (0.9) except for ADL. The validation statistics (standard error and correlation coefficient) were similar. In the diallel crosses, the estimates of variation (heritabilities in broad and narrow sense, genotypic and error coefficients of variation), generally, did not vary appreciably and consistently in the comparisons between Lab and NIRS methods particulary at silage harvest. Simple and rank correlations between Lab and NIRS analyses were positive and significant. These correlation coefficients based on the mean performance of the diallel crosses at silage harvest were >0.9 and at least 16 hybrids were common between the two analyses, among the upper one-third or lower one-third (22) hybrids. The study showed that NIRS analysis should be useful in maize breeding programmes wherein a large number of genotypes need to be evaluated.Abbreviations NIRS near infrared reflectance spectroscopy - Lab laboratory - IVDOM in vitro digestible organic matter - NDF neutral detergent fibre - ADF acid detergent fibre - ADL acid detergent lignin - SEC standard error of calibration - SEV standard error of validation - SD standard deviation - r simple correlation coefficient - r_s rank correlation coefficient - R² coefficient of multiple determination - h_b ² heritability in broad sense - h_n ² heritability in narrow sense - CV_g genotypic coefficient of variation - CV_e error coefficient of variation - GCA general combining ability effect     

Dry matter yield,nitrogen content,and competition in pea–cereal intercropping systems

Intercrops of pea (Pisum arvense L.), a popular legume used in intercropping systems with winter cereals for forage and silage production, with wheat (Triticum aestivum L.), rye (Secale cereale L.), and triticale (× Triticosecale Wittmack) in two seeding ratios (60:40 and 80:20) were compared with monocrops of pea and cereals for two growing seasons. Growth rate, dry matter yield, and N uptake were determined in each intercropping system. Furthermore, several indices were used to evaluate the intercropping systems and analyze the competition and the interrelationships between mixture components. Growth rate of cereals was lower in the mixtures than in the monocrops. Dry matter yield was higher in triticale monocrop, followed by its two intercrops, and the pea–wheat 80:20 intercrop. Moreover, triticale monocrop, pea–triticale intercrops, and pea–wheat 80:20 intercrop showed the highest crude protein yield and N uptake. The land equivalent ratio (LER), relative crowding coefficient (K), actual yield loss (AYL), and system productivity index (SPI) values were greater for the pea–triticale mixtures and the pea–wheat and pea–rye mixtures (80:20), indicating an advantage of intercropping. In most intercrops, the values of partial K, AYL, aggressivity, and competitive ratio (CR) indicated that the cereal was more competitive than pea. The highest values of monetary advantage index (MAI) and intercropping advantage (IA) were recorded for the pea–triticale and the pea–wheat mixtures (80:20). Overall, pea–triticale and pea–wheat mixtures (80:20) were more productive and produced better forage quality than the other mixtures and thus could be adopted by the farmers as alternative options for forage production.     

Response to divergent selection for ease of particle size reduction of dried leaves of smooth bromegrass ( Bromus inermis Leyss) and correlated effects on nutritive value indicators and plant fitness

The rate at which forage can be broken down and cleared from the rumen is a major constraint on voluntary intake by ruminants. Responsiveness to selection has been demonstrated for physical characters possibly related to the ease of breakdown of forage grasses and is a prerequisite for the exploitation of these characters in a breeding program. The objective of this study was to evaluate at two locations the response to one cycle of divergent selection for the ease of breakdown, or particle size reduction index (PSRI), of dried leaf blades in four populations of smooth bromegrass (Bromus inermis Leyss.) grown as spaced plants and the correlated response in neutral detergent fibre (NDF), in vitro dry matter digestibility (IVDMD) and on seedling performance and second year spread as indicators of plant fitness. Divergent selection for PSRI resulted in significant differences between high and low groups in all populations. The contrast for asymmetry of response was not significant, but response tended to be higher in the downwards direction relative to an unselected group. Realised heritabilities ranged from 10–21% when the unselected group was used to represent the parental generation. In the most responsive population, WB19e, seedling growth was poorer at both sites and seedling mortality higher at one site in plants selected for increased PSRI. Selection for PSRI had no effect on IVDMD but there were closely correlated changes in NDF (r = –0.73 across populations, p<0.01). However, comparisons between populations suggested that differences in PSRI independent of NDF also existed. PSRI can be exploited in a breeding program if gains in forage intake by ruminants, independent of changes in NDF, are demonstrated. This revised version was published online in July 2006 with corrections to the Cover Date.     

我国常用玉米自交系秸秆品质性状及其相关分析

利用近红外反射光谱法对我国91份常用普通玉米自交系和11份高油自交系秸秆的体外干物质消化率（IVDMD）、粗蛋白（CP）、粗脂肪（EE）、可溶性糖（WSC）、酸性洗涤纤维（ADF）、酸性木质素（ADL）、中性洗涤纤维（NDF）7个品质性状进行了分析评价,以探讨秸秆品质性状间的关系以及影响秸秆品质的主要成分。结果表明,各品质性状变异较大,各性状自交系间差异均达极显著水平,IVDMD及其相关品质的含量近似正态分布。不同品质性状变异程度不同,其中WSC含量变异最大,变异系数达33.15%。IVDMD与NDF、ADF、ADL呈极显著负相关,与WSC、EE含量呈极显著正相关,与CP含量显著正相关。影响秸秆品质的性状依次是IVDMD、ADF、NDF、WSC、ADL、CP和EE含量。根据青贮玉米育种的要求,筛选出5份IVDMD和WSC含量高、NDF、ADF含量低的自交系。     

Chemical Composition and Ruminal Dry Matter and Crude Protein Degradability of Spineless Cactus

The objective of this study was to determine ruminal degradability of the dry matter (DM) and crude protein (CP) of 10 varieties of spineless cactus (Opuntia spp.) grown in north‐eastern Brazil. Two ruminally fistulated steers were used in a randomized complete block design. Ash, CP, acid detergent fiber, and acid detergent lignin levels ranged from 10.4 to 13.3 %, 6.2–7.7 %, 19.8–24.8 % and 3.4–5.4 %, respectively. Relative to the other cactus varieties, Redonda had the highest (P < 0.05) in situ soluble DM fraction and effective DM degradability. No differences in effective DM degradability were observed between the other cactus varieties. In situ soluble CP fraction ranged from 1.7 % of CP for the 69 IPA/UFRPE variety to 11.1 % of CP for the Gigante variety. Slowly degradable CP fraction and its rate of degradation were similar among the cactus varieties (average 90 % of CP and 9 % h^?1, respectively). The cactus variety 69 IP/UFRPE had a lower (P < 0.05) effective ruminal CP degradability (ECPD) than the other varieties, which had a similar ECPD (average 66 % of CP). It was concluded that differences in ruminal degradability exist between cactus varieties, with more variations observed for ruminal DM than for CP degradability.     

Effects of Soil Moisture Deficit on Forage Quality, Digestibility, and Protein Fractionation of Kura Clover

Kura clover (Trifolium ambiguum M.B.) is a persistent rhizomatous forage legume with great potential for permanent pastures. The effects of a soil moisture deficit on forage quality, digestibility and protein fractionation of two cultivars of Kura clover (Endura and Rhizo) were investigated in this study for 1 year. The responses of alfalfa (Medicago sativa L.) and red clover (Trifolium pratense L.) were also characterized. Stands of each species were field‐grown and submitted to two soil water regimes promoting soil moisture deficits and well‐watered (i.e. control) conditions. There were no interactions between species and soil water regimes. Soil moisture deficit increased acid detergent fibre (ADF) but reduced acid detergent lignin (ADL) content and consequently increased forage digestibility. It had only minor effects on protein content and fractionation. Species varied for most parameters measured. Kura clover generally had the lowest neutral detergent fibre (NDF), ADF and ADL contents, and consequently the greatest digestibility (83.9 %). Species also differed in their crude protein fractionation. Kura clover and red clover had a lower proportion of non‐protein nitrogen (NPN; A fraction) and a greater proportion of true protein (B fraction) (30.9 and 64.5 %, respectively) than alfalfa (36.4 and 57.4 %, respectively). Kura clover also had the lowest proportion (i.e. 4.7 %) of acid detergent insoluble protein (ADIP; C fraction) of all species tested. Endura Kura clover often had a higher forage quality than Rhizo. This study confirms that Kura clover produces high‐quality forage and provides the first estimates of protein fractionation in this species.     

几种主要营养成分在大白菜不同叶片及部位中的分布规律

用近红外光谱法对５个大白菜品种从外向内分别测定每片叶片的叶柄及软叶的还原糖,Ｖc,ＮＤＦ,ＣＰ,ＤＷ５种有机成分,结果表明,不同叶片中,除软叶的Ｖc外,其余叶柄、软叶各有机成分都是由外向内逐渐增加,虽个别叶柄与软叶的含量有高有低,但上升的趋势是一致的;同一叶片中,软叶的还原糖和Ｖc都高于叶柄的含量,各品种软叶与叶柄的其它营养成分则有高有低,表现不一致;北京桔红心（９７－８）的还原糖,叶的ＶC,ＮＤＦ,ＣＰ含量是所有品种中最高的。     

Quantitative trait loci mapping of forage stover quality traits in six mapping populations derived from European elite maize germplasm

Four forage maize stover quality traits were analysed including in vitro digestibility of organic matter (IVDOM), neutral detergent fibre (NDF), water‐soluble carbohydrates (WSC) and digestibility of NDF (DNDF). We mapped quantitative trait loci (QTL) in three DH (doubled haploid) populations (totally 250–720 DH lines): one RIL population (358 lines) and two testcross (TC) populations, based on field phenotyping at multiple locations and years for each. High phenotypic and genotypic correlations were found for all traits and significant (p < .01) at two locations, and NDF was negatively correlated with the other traits. QTL analyses were conducted by composite interval mapping. A total of 33, 23, 32 and 25 QTL were identified for IVDOM, NDF, WSC and DNDF, respectively, with three, four, five and two major QTL for each. Few consistent QTL for IVDOM, WSC and DNDF were detected in more than two populations. This study contributed to the identification of key QTL associated with forage maize digestibility traits and is beneficial for marker‐assisted breeding and fine mapping of candidate genes associated with forage maize quality.     

Genetic basis of nutritional content of stover in maize under low nitrogen conditions

The effect of two different nitrogen treatments on five traits associated with yield and nutrient composition of stover were evaluated using a set of 213 F_2:3 families derived from two elite inbred lines Huang-C and Xu178. Evaluation of the phenotypes expressed under the two nitrogen conditions showed that low nitrogen conditions could increase acid detergent fiber (ADF) and neutral detergent fiber (NDF), and decreased crude protein content (CP), crude fat content (CF), and stover yield (SY), thereby negatively affecting the digestibility and quality of silage maize. Twenty-eight quantitative trait loci (QTL) were identified affecting the five measured traits under two nitrogen conditions, including four for ADF, five for NDF, five for CP, four for CF, and three for SY. Several QTL associated with ADF or NDF were detected under same nitrogen conditions, and were localized to the same chromosomal regions, especially the QTL qADF6 and qNDF6, qADF10 and qNDF10, were only detected under low nitrogen condition. These results suggested that ADF and NDF perhaps were controlled by several common genes, and that the nutritional content of stover may be influenced by additional genetic mechanisms when grown under conditions of low nitrogen.     

Condensed tannins in birdsfoot trefoil: Genetic relationships with forage yield and quality in NC-83 germplasm

Summary Genetic relationships of condensed tannins (CT) with other forage quality parameters have not been adequately studied in birdsfoot trefoil (Lotus corniculatus L.). The objectives were to bidirectionally select for CT concentration in birdsfoot trefoil to determine selection response and to create populations for examination of genetic relationships of CT with forage quality parameters, principally lignin. High-and low-tannin parental clones were selected from NC-83 birdsfoot trefoil germplasm and intercrossed to produce Syn₁ populations. Herbage samples, harvested for two years at two locations, were analyzed from high-tannin, low-tannin, and parental populations for CT concentration, herbage yield, and forage quality parameters. The mean condensed tannin concentrations in the high-and low-tannin populations were 69.3±0.8 and 21.1±0.8 g catechin equivalent (CE) kg^-1 dry matter (DM) compared with 36.4±0.8 g CE kg^-1 DM in the parental population. The selection response exhibited a quadratic relationship, with selection for increased CT concentration more effective than for reduced CT concentration. Compared with the parental population, acid detergent lignin (ADL) was higher, and crude protein (CP) and in vitro digestible dry matter (IVDDM) concentrations were lower for the high-tannin population and the converse was true for the low-tannin population. Lignin concentration was positively correlated with CT concentration (r_g=0.66 P0.01).Abbreviations ADF acid detergent fiber - ADL acid detergent lignin - CP crude protein - CT condensed tannins - IVDDM in vitro digestible dry matter - NDF neutral detergent fiber - NIRS near infrared reflectance spectroscopy     

Performance of Timothy-based Grass/Legume Mixtures in Cold Winter Region

This study sought to identify grass/legume mixtures that increase the yield and persistence of forage stands with improved nutritive quality in cold‐winter regions, compared with the standard mixture of timothy (Phleum pratense L.)/red clover (Trifolium pratense L.)/alsike clover (Trifolium hybridum L.). Timothy was mixed with either perennial ryegrass (Lolium perenne L.), meadow fescue (Festuca pratensis L.) or Kentucky bluegrass (Poa pratensis L.). The legumes in mixtures were red clover, alfalfa (Medicago sativa L.) or white clover (Trifolium repens L.). Averaged over three production years, the majority of mixtures had greater dry matter (DM) yields than the standard (8.35 t ha^?1). Timothy, grown alone and in three mixtures, outyielded the standard by 19–30 %. Yield reductions in mixtures over the 3‐year period were greatest with red clover, and least with bluegrass. Mixtures with alfalfa were highest in nitrogen (28.4 g kg^?1), while grasses grown alone (24.6 g kg^?1) and the standard mixture (25.1 g kg^?1) were the lowest in N. Mixtures with red clover or alfalfa had the least neutral detergent fibre (NDF), averaging 418 and 429 g kg^?1 respectively. Mixtures including white clover were initially low in NDF at 347 g kg^?1 in year 1 but increased to 550 g kg^?1 in year 3 as white clover composition declined in the sward.     

Potassium Management for Brown Midrib Sorghum × Sudangrass as Replacement for Corn Silage in the North-eastern USA

In recent years, there has been a growing interest in brown midrib (BMR) sorghum (Sorghum bicolor (L.) Moench.) × sudangrass (Sorghum sudanense Piper) hybrids (SxS) as a replacement for silage corn (Zea mays L.) in the north‐eastern USA. Recent studies suggest it is suitable for both rotational grazing and as a hay crop and could compete with corn harvested for silage in years when wet spring conditions prevent the timely planting of corn. However, little is known about its suitability as forage for non‐lactating cows that require low potassium (K) forages to prevent health problems. Our objective was to evaluate the impact of K fertilizer management (0, 112 or 224 kg K₂O ha^?1 cut^?1) under optimum N management (112–168 kg N ha^?1 cut^?1) on yield, quality and K concentrations of BMR SxS over a 2‐year period. Field trials were established on a fine loamy, mixed, active, mesic Aeric Fragiaquepts with medium K‐supplying capacity and characteristic of a large region in New York. Potassium application did not affect dry matter yields in either of the 2 years. Averaged over 2 years, neutral detergent fibre (NDF) significantly increased with K addition with similar but non‐significant trends observed in each of the years individually. The digestibility of NDF was unaffected by K application. Crude protein (CP) concentrations showed a significant decrease with K application in 2002 and similar trends were observed in 2003, although differences were not significant at P ≤ 0.05. The changes in NDF and CP did not significantly impact forage quality expressed as milk production per megagram of silage. Potassium application increased forage K concentration up to 13 mg K kg^?1 dry matter (in the first cut in 2003). Forage Ca and Mg concentrations decreased with K addition except for the first cut in 2002 where differences between 112 and 224 kg K₂O ha^?1 treatments were not significant. Without K addition in the 2‐year period, K concentrations in the forage decreased from 23 g kg^?1 for the first cutting in 2002 to 15 g kg^?1 for the second cut in 2003. Low K forage was obtained for all second‐cut forage unless 224 kg K₂O ha^?1 cut^?1 had been added. First‐cut forage was suitable only when no additional K had been applied. These results suggest low K BMR SxS forage can be harvested from initially high K soils without loss in dry matter yield as long as no additional K is added.     

Heritabilities of nutritive quality factors and interrelationships with yield in selected progenies of tall fescue

Nine polycross (PX) and nine different self (S₁) progenies were randomly chosen from 43 selected tall fescue genotypes and evaluated for in vitro digestible organic matter (IVDOM), crude protein, neutral detergent fibre, acid detergent fibre and acid detergent lignin of whole plants, leaf blades and stems (stem plus leaf sheath) at each of four harvest dates in 1991 and 1992. Significant variation for all whole‐plant and leaf quality traits occurred among the PX progenies at the May harvest. Variation among S₁ progenies was significant for almost all of the stem traits. Genetic variance components for both progeny groups were significant for almost all of the traits, confirming the presence of additive genetic variation. Heritability estimates on a progeny‐mean basis ranged from medium to high for almost all the traits of the whole‐plant and the leaf and stem fractions. The results suggest that spring would be the time at which direct selection for high IVDOM or low fibre content would be successful and that selection for leaf or stem quality traits improves whole‐plant quality. Selection for quality traits in the summer or in the autumn would be difficult since no significant genetic variability was found.     

Genetic analysis of feed quality and seed weight of sorghum inbred lines and hybrids using analytical methods and NIRS

Eight lines of grain sorghum and their F1hybrids were evaluated for contents of crude protein (CP), fat (FAT), and starch(STA); protein digestibility (PD); and in vitro dry matter disappearance (IVDMD).The effect of seed weight (SW) on these traits and the potential use of near infrared reflectance spectroscopy (NIRS) to predict them also were investigated. The male lines included three normal-seeded lines (TX2737, TX435, and P954063) and two large-seeded lines (PL-1 and Eastin1). The female lines included common U.S. seed parent lines (Wheatland, Redlan, andSA3042). The lines and their hybrids were grown under dry land conditions at Kansas State University experiment fields in Ashland and Belleville, Kansas, in 1999.The experiments were conducted using a randomized complete block design with four replications at each location. The effect of genotype was significant for all measured traits. The male parent lines were highly variable and expressed high levels of genetic variation in combining ability for CP, PD, STA, and SW. The female parents were genetically more uniform; however, significant general combining ability effects were noted for PD and SW. Significant negative correlations were noted between CP and STA and between SW and STA. Significant positive correlations were found between CP and SW and between FAT and IVDMD. Crude protein content was predicted accurately by NIRS. Fat content and IVDMD could not be predicted by NIRS. The NIRS equations based on ground samples were more accurate than those based on whole-seed samples. This revised version was published online in August 2006 with corrections to the Cover Date.     

Konkurrenz und Ertragsvorteile in Gemengen aus Erbsen (Pisum sativum L.) und Hafer (Avena sativa L.)

In field trials on a fertile fluvisol in 1995 and 1996 near Göttingen, Germany, pea (Pisum sativum; cv. Messire/conventional leafed, cv. Profi/semileafless) and oats (Avena sativa; cv. Alf) were grown as sole crops and in substitutive mixtures. The sole crops were established at 80 pea seeds m^?2 and 300 oat seeds m^?2. The mixtures consisted of 67 % (pea) and 33 % (oats) of the monoculture densities, respectively. Interactions of cv. Messire or cv. Profi and oats were similar in 1995 and 1996. The mixtures outyielded the monocultures with respect to total above ground dry matter (RYT = 1.15) and grain yield (RYT = 1.09). Grain yield of pea and oats averaged 4.9 t ha^?1 in monocultures and 5.5 t ha^?1 in mixtures. Oats was relatively the stronger of the two competitors. Decreasing number of pods per plant could be highlighted as the factor for a lower pea seed frequency in the yield of the mixtures. For oats the number of panicles per plant and kernels per panicle were higher in the mixtures compared with the oat monocultures. The average amount of the harvest index (HI) was 0.52 for pea and 0.46 for oats. Favourable growth conditions increased HI values however, prolific vegetative growth in the mixtures resulted in lower HI values. The predicted RYT‐values estimate the maximum combined grain yield of 6.3 t ha^?1 in the mixture of 87 % pea (70 seeds m^?2) and 13 % oats (39 kernels m^?2).     

Genetic variation and selection criterion for digestibility traits of forage maize

Summary Variations in feeding value characteristics were studied on a factorial mating design, within a multilocal network. The in vitro digestibility of dry matter (IVDDM), neutral detergent fiber (NDF), acid detergent fiber (ADF), acid detergent lignin (ADL), starch, soluble carbohydrate, protein and ash contents were evaluated on whole plant samples. The in vitro digestibility of the non-starch and non-soluble carbohydrate plant part (IVDNSC) was also computed from near infra-red reflectance spectroscopy estimations of IVDDM, starch and soluble carbohydrate contents. Variations due to general combining ability (GCA) were more important, for all traits, than variations due to specific combining ability (SCA). Variations due to the GCA × environment interaction were also sizeable and were partly explained by the earliness of the lines. IVDDM was primarily influenced by the relative proportions of cell walls and starch in the whole plant, which were particularly susceptible to the development stage of the plants, at harvest. When adjusted for earliness, there was generally no significant relation between the line per se value and GCA performance in the biochemical constituent contents of the plant. On the contrary, IVDNSC seemed to be a feeding value trait worth evaluating at the inbred line level. It was also almost independent of the ripening stage and could be easily computed from whole plant samples. IVDNSC, with a simultaneous control of starch content, might be a good selection criterion for evaluating and improving the nutritive value of forage maize.