Spring Oats Research Articles

Economic and Environmental Tradeoffs Among Alternative Seed Potato Rotations

ABSTRACT This study measures the economic and environmental outcomes associated with using two-, three- and four-year seed potato rotations in Southeastern Idaho. Seed potatoes are rotated with spring wheat, feed barley, oats, and canola. Crop yields, nitrogen loss, and soil erosion are simulated using the EPIC biological simulation model. A tradeoff frontier approach is used to screen out inferior rotations and to calculate tradeoffs between economic returns, reduced nitrogen loss, and reduced soil erosion. The results reveal that the most profitable and environmentally sound rotations tend to be three-year rotations of potatoes followed by two grain crops, with spring wheat occurring at least once in the crop sequence. A two-year potato-wheat rotation resulted in the largest economic return, a three-year potato-wheat-wheat rotation resulted in the second largest return and the smallest soil erosion, and a four-year potato-barley-wheat-wheat rotation resulted in the smallest nitrogen loss.

Genetically Engineering Elite Oat Cultivars

Previous work has shown that tissue cultures initiated from mature embryos of a specific experimental oat (Avena sativa L.) line, Gaf/Park, can be genetically engineered and fertile plants regenerated. The objectives of this study were to investigate the initiation of tissue cultures from mature embryos of 16 elite North American spring oat cultivars and to determine whether these tissue cultures can be used to produce transgenic plants. Fifteen of the genotypes tested produced at least some embryogenic callus that was similar in appearance to transformable callus. The elite cultivar Belle was tested to determine whether it could be genetically engineered. From 30 microprojectile bombardment treatments, 17 independently genetically engineered tissue cultures were produced that regenerated fertile, transgenic plants. These results indicate that the mature embryo‐derived tissue culture system will be useful for genetically engineering elite oat cultivars.

Effect of cultivar and fungicide treatment on the yield and nutritive value of winter and spring oat grains grown in England and Wales, 1989–91

The effect of a comprehensive (three-spray) fungicide programme on yield, specific weight (SW), 1000-grain weight (TGW), nutritive value and yield of both winter and spring oat grains was investigated over a 3-year period (1989–91). With winter oats, four cultivars (Aintree, Image or Pennal, Solva and Kynon), were tested at each of three sites (Gwent, Hereford and Kent). Similarly for spring oats, four cultivars (Dula, Keeper, Rollo and Rhiannon) were tested at each of three sites (Cornwall, North Yorkshire and Wales).On winter oats, fungicide treatment produced a significant increase (P<0·05) in grain yield, but did not on spring oats. Fungicide treatment produced no significant effect on SW, TGW or nutritive value of the winter or spring oats. With winter oats, but not with spring oats, fungicide treatment produced a significant increase (P<0·05) in the yield of digestible (DE) and metabolizable (ME) energy for pigs and ruminants respectively.The naked oats, Kynon and Rhiannon, had a significantly lower yield, higher SW and lower TGW than the other conventional cultivars (P<0·05). Their oil, fatty acid, protein, DE and ME contents were also significantly higher than the other cultivars (P<0·05). Nevertheless, the yield of protein, DE and ME tended to be less from naked oats than from some of the other cultivars tested.On winter oats, TGW, protein content and protein yield, dry matter (DM) and fatty acid content and on spring oats, yield, TGW, ME yield, DM, oil, fatty acid, protein, DE and ME all varied between years. With winter oats, oil content and energy values were negatively correlated with yield and positively correlated with SW. With spring oats, DE and ME were positively correlated with SW. It was concluded that, on winter oats, fungicide treatment was worthwhile in terms of grain yield, but this was not the case for spring oats. Also with winter oats, but not spring oats, fungicides gave useful increases in the yield of energy. The naked oats, Kynon and Rhiannon, had a distinct advantage in terms of nutritive value, but their low yield compared with the conventional cultivars tended to negate this benefit.

Fusarium Infection of Oat Varieties

It was found that F. culmorum and F. graminearum isolated from wheat were also virulent to spring oats. The degree of infection differed in the two years examined. Of the eight spring oat varieties examined ‘Muresan’ was less infected than the others. As the result of pathogen attack a substantial decrease was observed in thousand grain mass and in germination, thus causing a considerable reduction in the value of the seed.

The Nonselective Nature of a Modified Single‐Seed Descent Breeding Procedure

The objectives of this study were to determine (i) if selection for barley yellow dwarf virus (BYDV) tolerance occurred under a modified single‐seed descent (MSSD) procedure when used in conjunction with BYDV inoculation, and (ii) if changes in nuclear DNA content occurred during MSSD. Plants from four intraspecific spring oat (Avena sativa L.) crosses were grown in the greenhouse under a MSSD procedure and were infected with BYDV by inoculation with viruliferous aphids. These populations were compared with populations grown without exposure to BYDV. BYDV tolerance was evaluated in the field in the F4:5 and F4:6 generations. Inoculation with BYDV under the MSSD method did not selectively eliminate BYDV susceptible genotypes. To determine if the MSSD procedure induced selection for a particular nucleotype, seeds harvested from the parents (grown under the MSSD procedure) were tested for nuclear DNA content. No difference in DNA content was observed among progeny grown from seeds of stressed plants compared with progeny grown from seeds of nonstressed plants. These results suggest that even the most BYDV susceptible plants produced seeds during MSSD, and the MSSD method does not seem to induce directed changes in nuclear DNA content.

Yield Loss Assessment of Barley Yellow Dwarf Disease on Spring Oat in Illinois.

The quantitative relationship between yield of spring oat cvs. Ogle and Noble and incidence of barley yellow dwarf (BYD) disease caused by barley yellow dwarf virus (BYDV-PAV-IL) was studied. Field plots were infested with Rhopalosiphum padi vectoring BYDV-PAV-IL. A linear critical point regression model was developed that related percentage of maximum yield to BYD incidence, assessed by estimating the percentage of plants with BYD symptoms at Feekes growth stage 10.5 in each plot. The model y = 96.9 - 0.45x (r2 = 0.53) best explained the relationship. Test weight was unaffected by BYD. Although Noble consistently sustained higher disease incidence than Ogle, covariate analysis indicated that the effect of BYD on yield was similar for both cultivars. Studies of random versus focus inoculation of Noble oat, designed to determine the importance of compensation in reducing yield loss associated with BYD, indicated that compensation did not play an important role.

Breaking Uniculm Growth Habit of Spring Cereals at High Latitudes by Crop Management. I. Leaf Area Index and Biomass Accumulation

AbstractSpring cereals are commonly sown at high rates in Finland with the result that, under long day conditions, tillering is suppressed. If the apical dominance maintained by the shoot apex can be broken through altered crop management the possibility exists that the increased tillering allows a reduction in seeding rate. The objective of our study was to assess the effects of mechanical and chemical treatments, aimed at breaking the uniculm growth habit, on changes in green leaf area and consequently on biomass accumulation and partitioning in two spring oat, two spring barley, and two spring wheat cultivars. Results indicated that single applications of gibberellic acid (GA3), chlormequat chloride (CCC), and urea had no overall, persistent, advantageous effect on crop growth, even though occasional, temporary increases in LAI, and accumulation and partitioning of biomass, were recorded. Changes in crop structure, however, did not solely result from the increased contribution of tillers; treatments also accelerated main shoot growth. Following damage to the main shoot caused by mechanical treatments in particular, one of the tillers rapidly replaced the main shoot. Therefore, a low seeding rate associated with treatments aiming at breaking apical dominance cannot substitute for a high seeding rate at high latitudes. This was particularly the case in 1992 when early summer drought—prevalent in southern Finland ‐ resulted in peak values of LAI as low as ≤ 2 for wheat and ≤ 3 for oats and barley.

Insecticidal control of cereal aphids and its impact on the epidemiology of the barley yellow dwarf luteoviruses

Imidacloprid is a seed-applied nitroguanidine insecticide that has both contact and long-lasting systemic properties. Its direct effects on cereal aphid populations and indirect effects on barley yellow dwarf luteovirus (BYDV) incidence were examined in laboratory and field studies. Adult longevity and fecundity of three aphid species caged on various aged, imidacloprid-treated oat or wheat plants was reduced, although the quantitative efficacy of the compound differed among aphid species. The transmission efficiency of BYDV by aphids to imidacloprid-treated plants was lower, relative to nontreated plants, when plants were 10 days old, but similar to nontreated when plants were 24 days old. In three years of field trials using winter wheat and two years using spring oat, aphid populations were reduced significantly in imidacloprid-treated plots relative to nontreated plots. Although the number of alighting alate aphids did not differ significantly between imidacloprid-treated or nontreated plots, the number of apterous aphids remained significantly lower in the treated plots for the majority of the growing season. BYDV epidemics did not develop in spring oat in either of the two years. BYDV epidemics did develop in the fall in the emerging winter wheat crop. Rhopalosiphum maidis was the predominant aphid migrating into the 1991–1992 crop. The incidence of the BYDV-RMV serotype was three times higher in nontreated plots than in imidacloprid-treated plots. In the 1992–1993 and 1994–1995 seasons, R. maidis and R. padi were the predominant aphids migrating into the crop, although R. padi was the predominant colonizing aphid. The incidence of BYDV-RMV was similar in imidacloprid treated and nontreated plots in 1992–1993, but the incidence of the BYDV-PAV serotype was significantly less in the treated plots. In 1994–1995, the incidence of both BYDV-PAV and BYDV-RMV was higher in the nontreated plots than in the imidacloprid-treated plots. Imidacloprid offers several advantages both in terms of its long-lasting systemic activity and its mode of applicaiton. As a seed treatment, the amount of material applied is minimized, there is little waste and the environmental impacts are reduced. The effectiveness of the compound at reducing the fecundity or reproductive rate of several aphid species may be advantageous in controlling secondary spread of viruses. However, the contact properties of the compound, important in repelling aphids or preventing phloem feeding, may be short-lived, thus reducing its effectiveness in preventing primary spread of the virus into the crop, especially under high aphid and inoculum pressure.

Post‐harvest Evaluation of Nitrogen Sufficiency for Small‐grain Cereals by Measuring Grain Protein Concentration

AbstractNitrogen (N) fertilizer is an important and expensive input in small‐grain cereal production, and growers therefore should aim to optimize its use. Possibilities for using grain protein concentration for post‐harvesr evaluation of N sufficiency were determined in this study. Field experiments including spring wheat (Triticum aestivum L.), spong barley (Hordeum vulgare L) and spring oats (Avena sativa L.), and various rates of N fertilizer application were conducted in southern and western‐Finland over 2 years. Grain yield and grain protein were positively correlated and firred quadratic regression models. Both critical and optimum levels for grain protein concentration were determined by Cate‐Nelson analysis Critical values were 12.2 for wheat, 10.2 for barley and 10.9 for oats, and corresponding optimum values were 13.3, 11.1 and 12.7, respectively. The accuracy of the method was tested using results from on‐farm spring wheat trials. The results indicated that N fertilizer uptake and grain yield were best in held where gram protein concentration exceeded the critical values but not the optimum. Growers should use more intensive N fertilization management if grain protein concentration does not exceed critical values. Grain protein concentrations above optimum values indicate over‐fertilization for maximum grain yield. Analysing previous research data to identify the “critical level” of grain protein concentration is not difficult, and will provide powers, extension personnel, and fertilizer dealers with a cost effective means of evaluating the efficiency of N use by the crop and for developing N fertilization recommendations.

Diversity Among Isolates Within the PAV Serotype of Barley Yellow Dwarf Virus

Several barley yellow dwarf virus (BYDV) isolates collected from viruliferous aphids in upstate New York were identified as PAV serotypes, based on their reaction with a polyclonal antiserum to NY-PAV. Four of six isolates examined were distinguished from the NY-PAV type isolate of BYDV by their failure to react with a PAV-specific monoclonal antibody in enzyme-linked immunosorbent assay (ELISA) and by restriction fragment length polymorphisms of polymerase chain reaction-amplified viral sequences. The capsid protein amino acid sequence of one of these four isolates, designated PAV-129, was less similar to that of NY-PAV (86.5% similar) than NY-PAV is to two other isolates, serotyped as PAV, from Indiana (98% similar) or Australia (97% similar). In biological comparisons of PAV-129 and NY-PAV, the efficiency of transmission by two aphid species, Rhopalosiphum padi and Sitobion avenae, was not significantly different; however, PAV-129 caused more severe symptoms when inoculated to a variety of oat genotypes. In addition, the growth and grain yield of 'Ogle', a spring oat considered resistant to the BYDV PAV serotype was significantly reduced when infected with PAV-129.

Rate and Time of Nitrogen Application for Wheat following Different Crops

Winter wheat (Triticum aestivum L.) is often rotated with other crops in the eastern Great Plains to diversify cropping systems. Optimum management of N fertilizer is important for maximum profit potential and for avoiding environmental concerns. This study was conducted from 1986 through 1991 in southeastern Kansas to determine the influence of previous crop (grain sorghum [Sorghum bicolor (L.) Moench], soybean [Glycine max (L.) Merr.] and spring oat [Avena sativa L.]) on the N requirement for hard red winter wheat and to determine the optimum time of N application (fall, late winter, or fall + late winter and fall + late winter + early spring). Doublecrop soybean followed wheat in a 2-yr cropping rotation. Soil type was a Parsons silt loam soil (fine, mixed, thermic, Mollic Albaqualf) with 2.8% O.M. Influence of previous crop on wheat yield, grain protein, and plant N increased with time in the rotation sequence. Differences between previous crops were small after the first cropping cycle; however, after the third cycle, all values were significantly highest following spring oat and lowest following grain sorghum. Grain yield response to applied N was highest following grain sorghum, intermediate following soybean, and lowest following spring oat. Nitrogen response differences probably are due to a larger net mineralization of soil-N and crop residue N following spring oat than soybean or grain sorghum and to immobilization of applied N following grain sorghum. Number of heads per sq ft was highly correlated (R 2 = 0.85) with grain yield response. Split N (fall + late winter) and split-spring N (fall + late winter + early spring) applications generally showed no consistent yield advantage over single N treatments (fall preplant or late winter topdress). Grain protein, however, was often higher when N was delayed until late winter or early spring. Results indicate that fertilizer N requirements for hard winter wheat are likely to be low following another small grain crop, intermediate following soybean, and high following a high residue crop, such as grain sorghum. For the climatic and soil conditions in this study, applying N fertilizer at the proper rate was more important than timing of application. Applying up to 1/4 of the total N in early spring, however, could be beneficial for increasing grain protein content in hard winter wheat areas.

Registration of ‘INO9201’ Spring Oat

Crop ScienceVolume 35, Issue 3 cropsci1995.0011183X003500030059x p. 940-940 Registration of Cultivars Registration of ‘INO9201’ Spring Oat H. W. Ohm, Corresponding Author H. W. Ohm n/[email protected] Asgrow Seed Co., Inc., 7000 Portage Rd., Kalamazoo, MI, 49001Corresponding author.Search for more papers by this authorG. Shaner, G. Shaner Dep. of AgronomySearch for more papers by this authorG. Buechley, G. Buechley Dep. of AgronomySearch for more papers by this authorW. G. Aldridge, W. G. Aldridge Plant Sciences Dep., Univ. of Arizona, Tucson, AZ, 85721Search for more papers by this authorD. E. Bostwick, D. E. Bostwick USDA-ARS and Dep. of Entomology, Purdue Univ., West Lafayette, IN, 47907Search for more papers by this authorR. H. Ratcliffe, R. H. Ratcliffe Dep. of Botany and Plant PathologySearch for more papers by this author H. W. Ohm, Corresponding Author H. W. Ohm n/[email protected] Asgrow Seed Co., Inc., 7000 Portage Rd., Kalamazoo, MI, 49001Corresponding author.Search for more papers by this authorG. Shaner, G. Shaner Dep. of AgronomySearch for more papers by this authorG. Buechley, G. Buechley Dep. of AgronomySearch for more papers by this authorW. G. Aldridge, W. G. Aldridge Plant Sciences Dep., Univ. of Arizona, Tucson, AZ, 85721Search for more papers by this authorD. E. Bostwick, D. E. Bostwick USDA-ARS and Dep. of Entomology, Purdue Univ., West Lafayette, IN, 47907Search for more papers by this authorR. H. Ratcliffe, R. H. Ratcliffe Dep. of Botany and Plant PathologySearch for more papers by this author First published: 01 May 1995 https://doi.org/10.2135/cropsci1995.0011183X003500030059xCitations: 3AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article.Citing Literature Volume35, Issue3May–June 1995Pages 940-940 RelatedInformation

The Impact of Rotational Practice on Nitrate Leaching Losses in Organic Farming Systems in the United Kingdom

ABSTRACT The characteristics of organic farming involve the application of husbandry practices which are consistent with limiting nitrate leaching from agricultural land. The high losses of nitrate associated with ploughing of grass-clover leys are balanced by lower losses during the subsequent years of the arable and grassland phases of the rotation. Nitrate leaching data are presented from a monitoring programme carried out on 10 field sites on three commercial organic farms in the UK during the period 1988–92. Fields in arable and grassland phases of the farm rotations were monitored. Nitrate leaching was estimated from the nitrate concentration in soil water (sampled using porous ceramic cup samplers installed at 0.9 m soil depth) integrated with cumulative net drainage. The rotations operated on the farms were 5 to 8 years duration, including grass/clover for grazing and conservation, winter and spring wheat, winter and spring oats and potatoes. Average annual losses from these rotations calculated using the data derived from the monitored fields ranged between 10–21 kg Nha−1 yr−1. It is concluded that organic farming systems in the UK may have a valuable role to play in limiting nitrate leaching and should be considered for use in water protection zones.

Rotation effects on sustainability of crop production: the Glen Innes rotation experiment

This study, which commenced in 1921, is the longest running crop rotation experiment in the summer rainfall region of Australia. The 7 rotation treatments comprise various frequencies and combinations of maize and spring oat crops with and without autumn oats and red clover ley. The maize and oat yields are analysed separately using principles described by Paterson (1964). Spline regressions are used to describe the trends of yields with time and to make comparisons amongst the rotations. Yield performance of maize and oats was improved as legume ley duration increased, although as maize cropping became more frequent this effect was reduced. Autumn-sown oats benefited both maize and spring oat yields, independent of the presence of a legume ley. Crop yields were generally maintained in those rotations containing a grazed clover ley. After alteration of ley management in the mid 1960s so that clover crops were subsequently removed as hay, crop yields in these rotations declined. The benefits of clover ley to crop productivity were considered to be primarily due to the maintenance of those soil chemical, physical, and biological properties associated with sustainable crop production.

A Comparison of Freezing Injury in Oat and Rye: Two Cereals at the Extremes of Freezing Tolerance.

A detailed analysis of cold acclimation of a winter rye (Secale cereale L. cv Puma), a winter oat (Avena sativa L. cv Kanota), and a spring oat cultivar (Ogle) revealed that freezing injury of leaves of nonacclimated seedlings occurred at -2[deg]C in both the winter and spring cultivars of oat but did not occur in winter rye leaves until after freezing at -4[deg]C. The maximum freezing tolerance was attained in all cultivars after 4 weeks of cold acclimation, and the temperature at which 50% electrolyte leakage occurred decreased to -8[deg]C for spring oat, -10[deg]C for winter oat, and -21[deg]C for winter rye. In protoplasts isolated from leaves of nonacclimated spring oat, expansion-induced lysis was the predominant form of injury over the range of -2 to -4[deg]C. At temperatures lower than -4[deg]C, loss of osmotic responsiveness, which was associated with the formation of the hexagonal II phase in the plasma membrane and subtending lamellae, was the predominant form of injury. In protoplasts isolated from leaves of cold-acclimated oat, loss of osmotic responsiveness was the predominant form of injury at all injurious temperatures; however, the hexagonal II phase was not observed. Rather, injury was associated with the occurrence of localized deviations of the plasma membrane fracture plane to closely appressed lamellae, which we refer to as the "fracture-jump lesion." Although the freeze-induced lesions in the plasma membrane of protoplasts of spring oat were identical with those reported previously for protoplasts of winter rye, they occurred at significantly higher temperatures that correspond to the lethal freezing temperature.

Occurrence of oat stem rust in west Wales

The first significant occurrence of stem rust (Puccinia graminis Pers, ssp, graminis var, stakmanii Guyot, Massenot & Saccas ex, Urban) on spring oats (Avena sativa L.) in west Wales, UK is reported.

A Contrast of the Plasma Membrane Lipid Composition of Oat and Rye Leaves in Relation to Freezing Tolerance.

The lipid composition of the plasma membrane isolated from leaves of spring oat (Avena sativa L. cv Ogle) was vastly different from that of winter rye (Secale cereale L. cv Puma). The plasma membrane of spring oat contained large proportions of phospholipids (28.8 mol% of the total lipids), cerebrosides (27.2 mol%), and acylated sterylglucosides (27.3 mol%) with lesser proportions of free sterols (8.4 mol%) and sterylglucosides (5.6 mol%). In contrast, the plasma membrane of winter rye contained a greater proportion of phospholipids (36.6 mol%), and there was a lower proportion of cerebrosides (16.4 mol%); free sterols (38.1 mol%) were the predominant sterols, with lesser proportions of sterylglucosides (5.6 mol%) and acylated sterylglucosides (2.9 mol%). Although the relative proportions of individual phospholipids, primarily phosphatidylcholine and phosphatidylethanolamine, and the molecular species of these two phospholipids were similar in oat and rye, the relative proportions of di-unsaturated species of these two phospholipids were substantially lower in oat than in rye. The relative proportions of sterol species in oat were different from those in rye; the molecular species of cerebrosides were similar in oat and rye, with only slight differences in the proportions of the individual species. After 4 weeks of cold acclimation, the proportion of phospholipids increased significantly in both oat (from 28.8 to 36.8 mol%) and rye (from 36.6 to 43.3 mol%) as a result of increases in the proportions of phosphatidylcholine and phosphatidylethanolamine. For both oat and rye, the relative proportions of di-unsaturated species increased after cold acclimation, but the increase was greater in rye than in oat. In both oat and rye, this increase occurred largely during the first week of cold acclimation. During the 4 weeks of cold acclimation, there was a progressive decrease in the proportion of cerebrosides in the plasma membrane of rye (from 16.4 to 10.5 mol%), but there was only a small decrease in oat (from 27.2 to 24.2 mol%). In both oat and rye, there were only small changes in the proportions of free sterols and sterol derivatives during cold acclimation. Consequently, the proportions of both acylated sterylglucosides and cerebrosides remained substantially higher in oat than in rye after cold acclimation. The relationship between these differences in the plasma membrane lipid composition of oat and rye and their freezing tolerance is presented.

Reduction of Disease Incidence in Small Field Plots by Isolate-Specific Resistance to Barley Yellow Dwarf Virus

Epidemics of 2 isolates, RMV and MAV, of barley yellow dwarf luteovirus (BYDV) were studied in 3 spring oat genotypes in Ithaca, New York, USA. Two of the genotypes were previously found to possess varying levels of resistance expressed as a reduction in the accumulation of virus antigen titre in plants. The reduced virus antigen titre contributed to reduced virus acquisition and transmission efficiencies by aphid vectors. The third genotype was susceptible to the 2 BYDV isolates. Resistance was expressed at high levels against the RMV isolate; and in 1990 and 1991, the final disease incidence of RMV and rate of disease progress were significantly reduced in the resistant genotypes relative to the susceptible genotype. The resistance reduced both rate of disease progress and final disease incidence of the MAV isolate during both years of study. The magnitude of the reduction in final MAV incidence relative to the susceptible genotype varied between the 2 years and could be related to vector population intensity and environmental factors. It is suggested that resistance expressed as reduced or suppressed virus accumulation in plants can be easily identified by serological or nucleic acid-based assays. The lower virus titre may reduce disease impact on plant growth and can reduce the efficiency with which aphid vectors acquire and transmit virus among resistant plants.

Yield Loss in Two Spring Oat Cultivars due toPuccinia coronataf. sp.avenaein the Presence or Absence of Barley Yellow Dwarf Virus

Individual studies were done to estimate yield loss due to Puccinia coronata f. sp. avenae (crown rust) in the presence or absence of barley yellow dwarf virus (BYDV-PAV-IL) for two spring oat cultivars at two locations. Crown rust disease severity was assessed several times and related to yield and yield components. Linear critical point regression models were developed with analysis of covariance. Yield loss for each percent increase in crown rust severity (modified Cobb scale A) was 56,7 kg/ha for cv. Noble and 46.0 kg/ha for cv. Ogle. Test weight decrease for each percent increase in crown rust severity was 1.2 kg/m 3 for Noble and 1.1 kg/m 3 for Ogle. Ogle exhibited tolerance to yield loss from crown rust [...]

Response of forage yield and yield components to planting date and silage/pasture management in spring seeded winter cereal/spring oat cropping systems

Spring-planted mixtures of spring and winter cereals in a silage/fall pasture system have been shown to extend the grazing season in the Parkland of the Canadian prairies. Experiments were conducted at Lacombe, Alberta to determine the effects of planting date on yield and yield components of spring-seeded spring oat (Avena sativa L.), winter wheat (Triticum aestivum L.), winter triticale (X Triticosecale Wittmack) and winter rye (Secale cereale L.). The cereals were grown as monocrops or as binary mixtures of the oat and winter cereals. Treatments were planted in early May and mid-June and harvested twice for forage. The initial harvest for early and late planting dates occurred when oat reached the early-milk and heading stages, respectively. Regrowth was harvested in mid- to late September. The planting date x treatment interaction did not affect (P ≤ 0.05) annual yield (initial + regrowth) even though oat was harvested at different developmental stages. Averaged over treatments, late planting reduced annual yield by 42%. The annual yields ranked: mixtures = oat monocrop > winter cereals. Late planting date reduced the initial yield of all treatments, but the winter monocrops were reduced less than oat. Oat dominated the initial yield of all mixtures. Although oat tiller density was lower in the mixtures than monocropped oat at the initial cut, oat constituted a greater proportion of the mixture than would have been expected from the seeding ratio (1:1). A larger tiller weight in the oat mixture vs. the monocrop may have compensated for low tiller density in the mixture. Mixture regrowth yields tended to be greater in late-planted treatments and were dominated by the winter cereals. Although the winter cereal component of the mixture had more tillers at the regrowth cut, they still had lower yields when compared with their respective monocrops. Thus, late planting reduced annual yields of mixtures and monocrops, but did not limit regrowth of winter cereals in mixtures given equal regrowth periods. Key words: Oat, winter rye, winter wheat, winter triticale, forage yield, tillering