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1.
C. Oertel    J. Fuchs  F. Matzk 《Plant Breeding》1996,115(2):101-105
In order to test crossability of Lolium and Dactylis, a total of 4126 florets of six different varieties and ploidy levels of Lolium multiflorum Lam. and L. perenne L. were pollinated using a blend of pollen from two cultivars and three ecotypes of Dactylis glomerata L. Additionally, reciprocal pollinations were carried out on 363 florets of two D. glomerata cultivars with pollen of L. multiflorum. Both pre- and post-zygotic cross barriers were strong. Auxin application was effective in overcoming post-zygotic barriers. One viable hybrid plant arose from 16 embryos. The hybrid between L. multiflorum and D. glomerata showed characteristics of both parents. The symmetric character of the hybrid was confirmed by genomic in situ hybridization. Backcross pollinations with pollen of both parents yielded two plants from five embryos with L. multiflorum only. Both the production of allopolyploid hybrids having characters of both species and the transfer of useful characters of D. glomerata into L. multiflorum should be possible.  相似文献   

2.
In a two year factorial field trial the influence of slight shading (daylight reduced by 27 %), row spacing (15 and 30 cm respectively) and N fertilization (60 and 120 kg* ha?1*cut?1 respectively) on yield and nutritive value of Lolium multiflorum (Lam.) was investigated. Three cuts were taken in the seeding year and four in the full harvest year. Shading reduced DM yield by 4 % at low and 16 % at high level of N fertilization. Higher amount of N fertilizer increased yield by 28 % without and 12 % with shading. Row spacing was of minor importance; on average wider spacing decreased yield by 9 %. Increasing N fertilization and shading had the same effects on nutritive value: crude protein (CP), nitrate content and protein/energy ratio (P/E) went up, whereas energy value (NEL) went down. Compared to the effects of shading or N fertilization, the influence of sward density on nutritive value was small. The effect of shading and high fertilization on nutritive value was similar in both years. However for vegetatively grown forage in the seeding year shading caused P/E values and nitrate contents too high for an adequate ruminant feeding which was already evident at low level of N fertilization; also increased supply of N fertilizer without shading deteriorated the nutritive value. On the other hand forage of the full harvest year (at reproductive stages) showed too high P/E values only in shaded and highly fertilized plots. Therefore N fertilization ought to be limited at periods when the grass only grows vegetatively and/or light intensity is low, like e.g. in autumn. None of the experimental treatments had any marked effect on the fibre content of the forage (ADF) in the seeding year; in the full harvest year, however, when plants grew reproductively, shading as well as higher N fertilization increased ADF content. There was no significant correlation between ADF and NEL for vegetatively grown plants but a close relation for plants which were at reproductive stages.  相似文献   

3.
In de‐intensified grassland where an increased seedling recruitment is seen as a prerequisite to enhance plant species diversity, establishment success of introduced seeds of wildflower species is often poor. Outshading by the existing sward and dry weather spells when seedlings are at an early stage of development are major reasons for a low seedling establishment. The effects of drought and competition by an existing Lolium perenne sward on the growth of seedlings of seven wildflower species were investigated under standardized environmental conditions. Without competition (control), the relative growth rate of the wildflower seedlings varied between 103 (Tragopogon pratensis) and 184 mg g?1 day?1 (Leontodon autumnalis). Species differed in the extent of growth reduction by competition. Compared with the control, reduction of seedling dry weight ranged from 45 % (Trifolium pratense) up to 88 % (Daucus carota). The time range between onset of desiccation and first effects on growth varied between species, with T. pratense showing early and strong growth reduction in contrast to D. carota being least affected. It can be concluded, that those species which maintain a comparatively high growth rate supported by adapted shoot‐root allocation are most promising for establishment in grassland as they can exploit profiles of higher resource availability.  相似文献   

4.
Regrowth characteristics of a cocksfoot (Dactylis glomerata L.) sward after initial defoliation at different stages of development Over 2 two-year period (1984-1985) the productivity of Dactylis glomerata (cv. Baraula) swards as influenced by variations in time of the initial defoliation was studied. The stages at which the initial cuts were taken were: (a) before stem apices were raised to defoliation level (5 cm), (b) about two weeks later, when the reproductive tillers reached ear emergence, (c) about 4 weeks after (a), when the reproductive tillers reached flowering stages. Subsequent production was measured by weekly harvesting of representative sward samples over a 6-7 weeks lastening growth period. Furtheron patterns of growth in a second regrowth in August and a third regrowth in September/October were studied. The growth behaviour in the investigation was described by calculations of curves concerning mainly the development of dry matter yield (DM), leaf area index (LAI), crop growth rate (C), relative growth rate (R) and net assimilation rate (E) during the growth period. The leaf area ratio (F) and leaf weight ratio (LWR) were derived from fitted curves. The highest dry matter yield and the highest growth rate (more than 20 g m?2day?1) was estimated in the spring growth and in the earliest regrowth (a). About 30 % of the tillers in these swards became reproductive. The main difference between regrowths of primary defoliations at successively later dates was between the earliest, after cutting on 8.-13. May, on the one hand, and, on the other hand, the two later regrowths after primary cuts from 31. May to 12. June. The two latter and the second regrowth in August were in most respects very similar: no reproductive development; herbage yield of about 400-500 g m?2; highest C of about 15-20 g m?2day?1; maximum LAI- values from 8-9. In respect to the E there were some differences between the stands. The E was at the time when C was highest somewhat higher in the reproduction stands (spring growth and first regrowth) compared with the vegetative regrowths. The relationship between C and LAI could in all stands be described by an relatively optimum curve, which means that C did not differ much within a wide range of LAI.  相似文献   

5.
New opportunities for plant breeding using androgenesis in Lolium × Festuca hybrids have been identified. Plants derived by anther culture from a Lolium multiflorum × Festuca arundinacea (5x) hybrid were screened for freezing-tolerance, and their post-freezing recovery compared. The androgenic population showed extreme diversity in freezing-tolerance. While the majority of androgenic plants had inferior freezing-tolerance compared with the freezing-sensitive L. multiflorum parent, 6% of the population were more freezing resistant than the freezing-tolerant Festuca parent. Novel Lolium and Festuca gene combinations resulting from rare meiotic events were recovered within the androgenic population. The two most freezing-tolerant androgenic plants carried virtually the entire F. pratensis subgenome of F. arundinacea. F. pratensis is known to carry genes for freezing-tolerance and would be expected to be the primary source of genes governing this trait within the F. arundinacea genome. The most freezing-tolerant androgenic plants were more freezing-tolerant than the hybrid plant from which they were derived. Consequently, androgenesis was also effective in removing factor(s) reducing the expression of freezing-tolerance within the L. multiflorum × F. arundinacea (5x) hybrid.  相似文献   

6.
Selection for improved nitrogen-utilization in Lolium
In a 3-year study the responses of 14 Lolium perenne-varieties and 14 of Lolium multiflorum to different nitrogen fertilization (75, 150, 300 kg N/ha) were investigated. The varieties were classificated into four types of nitrogen utilization. "Low input varieties" can be found in type III. The varieties of this type produced always the highest yield at all levels of nitrogen fertilization. The yield of type I was always smaller than the average of all varieties. The varieties of type II gave significant better responses than the trial average up to 150 kg N/ha. Under low and high N-fertilization the type III can be separate of type I and II because it is always the outstanding variety. The dry matter production of the roots did not show varieties differences under the increasing N-fertilization. The soil nitrate contents were with 20 kg nitrate nitrogen per ha very small.  相似文献   

7.
Two diploid (Belramo and Glen), one tetraploid (Rosalin) and one tetraploid hybrid (Lolium× boucheanum Kunth) (AberExcel) intermediate-heading perennial ryegrass (Lolium perenne L.) varieties were sown in boxes (85×44×14 cm) to create micro-swards. Once established, these were defoliated at approximately 21-day intervals before being offered to individual yearling Simmental × Holstein beef heifers in short-term tests. Bite mass measured in these tests was compared with bite mass for groups of similar heifers which were rotationally stocked on the same four varieties. The boxes were weighed (± 0.1 g) before and after a period during which the heifers were allowed to take approximately 50 bites. The micro-sward methodology was developed in, 2002 and bite masses for Belramo, Glen, Rosalin and AberExcel, respectively, were 0.44, 0.46, 0.49 and 0.50 g DM bite–1 compared with 0.48, 0.49, 0.50 and 0.50 g DM bite–1 measured for rotationally stocked cattle. In 2003, the values for bite mass were 0.40, 0.41, 0.41 and 0.43 g DM bite–1 measured using sward boxes and 0.31, 0.41, 0.34 and 0.37 g DM bite–1 for rotationally stocked cattle. Whilst the rankings were similar within ploidy for the two assessment methods, there were no significant differences between the varieties. The micro-sward methodology provides a rapid, low-cost assessment method with a low seed requirement to screen for intake traits during breeding programmes and during variety evaluation. Now there is a need to develop further this methodology in order to allow small-scale simulation of other defoliation regimes, for example continuous stocking.  相似文献   

8.
G. Kleijer 《Plant Breeding》1987,99(2):144-150
Meiotic observations of 56-chromosome plants of the C1, C2 and C3 generations of the amphidiploid Lolium multiflorum × Festuca arundinacea showed that most of the chromosomes paired as bivalents. However, uni- and multivalents were frequently observed. No difference in meiotic regularity and stability could be detected between the different generations. The average chromosome number and; the percentage of 56-chromosome plants decreased with increasing generations. The direct use of the 56-chromosome amphidiploids of L. multiflorum and F. arundinacea in a breeding programme appears to be quite difficult, but these plants can be used in a backcross programme with Lolium and Festuca.  相似文献   

9.
Increased recovery and recycling of manure phosphorus (P) by crops on dairy farms is needed to minimize environmental problems. The main objective of this study was to compare P utilization by orchardgrass (Dactylis glomerata L.) and tall fescue (Festuca arundinaceae Schreb.) from dairy manure or inorganic fertilizer. The study was conducted from 1994 to 2000 at the Cornell University Baker Farm, Willsboro, NY, on a somewhat poorly drained Kingsbury clay (very–fine, illitic, mesic Aeric Epiaqualfs). The design was a split‐plot in a randomized complete block with two manure rates (16 800 and 33 600 kg ha?1) and one nitrogen (N) fertilizer rate (84 kg N ha?1 at spring greenup and 56 kg N ha?1 prior to each regrowth harvest) as the main plots and grass species as subplots replicated six times. Fertilizer P [Ca(H2PO4)2] was applied to the fertilizer treatment in 1995 and 1996 at 11 kg P ha?1 year?1. Orchardgrass P removal averaged 21 % higher than tall fescue P removal for the spring harvest, but orchardgrass averaged 24 % lower P removal than tall fescue removal for all regrowth harvests from 1995–99. Phosphorus herbage concentration in the fertilizer treatment was in the range of 1.9–2.7 g P kg?1 compared with 2.2–5.3 g P kg?1 in the manure treatments. Seasonal P removal ranged from as low as 9.2 kg P ha?1 to as high as 48.5 kg P ha?1. Morgan extractable soil P in the top 0–0.20 m remained high through 1999, with 29.1 kg P ha?1 at the highest manure rate in tall fescue compared with 8.4 kg P ha?1 measured in 1993 prior to the experiment. In 2000, soil P at the highest manure rate in tall fescue dropped to 10.1 kg P ha?1, following cessation of manure application in 1998. Intensively managed harvested orchardgrass and tall fescue have the potential to remove large quantities of manure P.  相似文献   

10.
Three widely used cultivars of each of the species Festuca pratensis Huds., Lolium perenne L., and Dactylis glomerata L. were investigated by means of randomly amplified polymorphic DNA (RAPD) markers and vegetative growth traits in order to investigate genetic variability within each cultivar and to compare the level of diversity among cultivars and species. RAPD markers allowed a clear separation of the three species. Genetic variability based on RAPD markers was considerably lower for F. pratensis cultivars than for L. perenne and D. glomerata cultivars which showed similar levels of variability. The proportion of variability due to variation within cultivars, determined by an analysis of molecular variance, was lower in F. pratensis (64.6%) than in L. perenne (82.4%) and D. glomerata (85.1%). A comparison of F. pratensis and L. perenne, based on vegetative growth traits, confirmed the differences in genetic variability within cultivars. F. pratensis showed lower coefficients of genetic variation for eight of ten traits when compared to L. perenne. This study demonstrates considerable differences in genetic variability which may have consequences for the adaptability and persistency of individual cultivars. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

11.
Reed canarygrass (Phalaris arundinacea L.) is often planted at wastewater treatment sites to provide ground cover and remove nutrients. Our overall objective was to determine the forage yield and nutrient uptake under year-round potato wastewater application in northern latitudes. Specifically, we determined the effect of N fertilization rate on forage dry matter yield and N and P uptake by reed canarygrass, and compared the forage yield, persistence and nutrient uptake of reed canarygrass relative to those of orchardgrass (Dactylis glomerata L.), smooth bromegrass (Bromis inermis Leyss), timothy (Phleum pratense L.) and quackgrass [Elytrigia repens (L.) Nevski]. With only wastewater application, reed canarygrass had a forage yield of 5.8 Mg ha−1, with N and P uptake of 113 and 30 kg ha−1, respectively. Forage dry matter yield, N uptake and P uptake increased to 14.5 Mg ha−1, 383 kg ha−1 and 64 kg ha−1, respectively, with an N fertilization rate of 224 kg ha−1. Forage yield and N uptake of reed canarygrass, orchardgrass, timothy and smooth bromegrass were similar and exceeded those of quackgrass. Reed canarygrass P uptake exceeded that of the other grasses. Reed canarygrass was less persistent than quackgrass or smooth bromegrass.  相似文献   

12.
Field experiments were conducted at Indian Agricultural Research Institute, New Delhi, during 2001–2002 and 2002–2003, to study the effect of inorganic, organic and Azotobacter combined sources of N on cotton (Gossypium hirsutum L.) and their residual effect on succeeding wheat (Triticum aestivum L.) crop. The results indicated considerable increase in yield attributes and mean seed cotton yield (2.33 Mg ha?1) with the combined application of 30 kg N and farmyard manure (FYM) at 12 Mg ha?1 along with Azotobacter (M4). The treatment in cotton that included FYM, especially when fertilizer N was also applied could either improve or maintain the soil fertility status in terms of available N, P and K. Distinct increase in yield attributes and grain yield of wheat was observed with the residual effect of integrated application of 30 kg N ha?1 + FYM at 12 Mg ha?1 + Azotobacter. Direct application of 120 kg N ha?1 resulted 67.4 and 17.7 % increase in mean grain yield of wheat over no N and 60 kg N ha?1, respectively. Integrated application of organic and inorganic fertilizer is therefore, recommended for higher productivity and sustainability of the cotton–wheat system.  相似文献   

13.
When grassland is ploughed and reseeded this results in an increased mineralization of organically bound nitrogen (N) in the soil. Greater amounts of nitrate in autumn are at risk of being leached during the winter half of the year. In two field experiments, nitrate leaching was measured over 2 years after reseeding of a 9‐year‐old grassland field in spring on a sandy soil in northwest Germany. During the experiments, major management factors that can influence the intensity of mineralization were varied: Type of fertilizer, mineral N fertilizer or organic manure, and the level of fertilization, 0, 160 or 320 kg N ha−1 a−1, before renewal of the grassland, and level of fertilization, 0, 160 or 320 kg N ha−1 a−1 in mineral form, after renewal of the grassland. The type of fertilization as well as the level of N fertilization before ploughing had no significant effect on the soil mineral nitrogen content (SMN) in autumn and N leaching in the year following the grassland renewal. N fertilizer level after sward renovation had a significant effect on the nitrate leaching losses in the two following years. Fertilization at a rate of 320 kg N ha−1 resulted in leaching losses of 7 and 61 kg N ha−1 in the first and second subsequent years, respectively. At fertilizer rates of 0 and 160 kg N ha−1 leaching losses were lower than 5 kg N ha−1. It is concluded that for mown grassland no restriction of the N fertilization before the renovation of the sward is necessary to reduce the nitrate leaching risk as long as the amount of N fertilized does not exceed the N‐uptake by the crop. Similarly, the N fertilization after the sward renewal does not bear a particular leaching risk.  相似文献   

14.
C. Oertel  F. Matzk 《Plant Breeding》1999,118(6):491-496
Crown rust, Puccinia coronata Corda, causes one of the most damaging foliar diseases in Italian ryegrass, Lolium multiflorum Lam. For introgression of crown rust resistance, highly resistant hybrids of the crosses Festuca arundinacea (2n = 6x = 42) ×L. multiflorum (2n = 4x = 28) and reciprocally, L. multiflorum (2n = 2x = 14) ×Festuca pratensis (2n = 4x = 28) and subsequently resistant recombinant individuals were used as female parents and susceptible cultivars of Italian ryegrass as male parents in three successive backcrosses. The BC3 plants were selfed and crossed mutually. Uredospores of seven different crown rust isolates collected from plants of L. multiflorum, Lolium perenne, F. pratensis, F. arundinacea and L. multiflorum × F. pratensis hybrids were applied to identify the resistance or susceptibility of the parental species, backcrossed, selfed and intercrossed progenies. The various crown rust populations revealed a species-specific capability to infect plants of the Lolium-Festuca complex corresponding to the host species from which the spores originated. Selected BC9 plants, however, were found to be completely resistant to all crown rust populations tested. Successful introgression of the resistance was achieved from F. arundinacea as well as from F. pratensis. The resistance represents a dominant character, apparently based on a strong heterologous incompatibility between host and pathogen. In phenotype, bivalent formation during meiosis and in fertility, the novel germplasms are comparable with the L. multiflorum cultivars.  相似文献   

15.
An improved method is reported for polyploid induction in Lolium (ryegrass), and in sterile F1 hybrids between Lolium and Festuca (fescue). Two factors greatly increased the survival rate of colchicine‐treated embryos of Lolium perenne (perennial ryegrass) germinated and cultured in vitro (1) a high concentration of sucrose (100 g/1) in the germination medium and (1), maintenance at a low temperature of 10°C for 2 weeks after treatment. The maximum success rate for chromosome doubling among survivors of perennial ryegrass was 79.1%, and for L. perenne×Festuca arundinacea F1 hybrid embryos it exceeded 40%. The same doubling treatment also works with shoot tip culture in non‐ flowering genotypes obtained by anther culture of L. multiflorum×F. arundinacea hybrids.  相似文献   

16.
Italian ryegrass (Lolium multiflorum Lam.) and perennial ryegrass (L. perenne L.) can be grown for seed and forage in cold winter regions provided the stand persists well over winter. Seed yield and plant characteristics during primary growth, and forage yield during regrowth, were determined for two Italian and one perennial ryegrass cultivars in Atlantic Canada. Establishment methods and dates included sowing ryegrass in cultivated soil alone or with barley in mid‐May and, after harvesting the barley crop, by sowing ryegrass following conventional or reduced cultivation and by no‐till drilling into barley stubble in mid‐August and early September. Despite some winterkill, particularly in Italian ryegrass, seed and forage yields were adequate in post‐establishment growing seasons. Seed yield for Italian ryegrass was greatest (1270 kg ha?1) when it was sown into cultivated soil in mid‐August and least (890 kg ha?1) when sown alone in May. Italian ryegrass yielded 15–17 % more seed when plots were established in mid‐August rather than in mid‐May or early September. Italian ryegrass cv. Lemtal had a greater density of fertile tillers (1030 m?2) in the sward than cv. Ajax (860 m?2) and its tiller density was greater when seeded into cultivated soil in September than in mid‐August. There were fewer spikelets per seed head for sowing Italian ryegrass with barley in May than for the other methods of establishment. Forage yield in regrowth was greater for Italian ryegrass cv. Ajax (2770 kg ha?1) than for cv. Lemtal (2480 kg ha?1). Seed yield of perennial ryegrass was greater when seeded in mid‐May than in mid‐August or early September. The seed yield of perennial ryegrass was greater when it was sown with barley in May and harvested for grain, than when it was sown alone or with barley harvested at late milk stage. The establishment methods for mid‐August and early September sowing had little effect on seed yield. However, the no‐till and reduced tillage methods resulted in a greater tiller density than sowing into the cultivated seedbed. Fertile tillers tended to be denser under reduced cultivation for sowing in August. Forage yield of perennial ryegrass regrowth was not influenced by the sowing method and timing. In conclusion, Italian and perennial ryegrasses produce adequate seed and forage regrowth under different establishment methods and timing. However, the poor persistence of Italian ryegrass may limit commercial production after the establishment year in Atlantic Canada.  相似文献   

17.
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).  相似文献   

18.
Economic Aspects of Breeding for Yield and Quality Traits in Forage Maize   总被引:2,自引:0,他引:2  
H. F. Utz    A. E. Melchinger    G. Seitz    M. Mistele  J. Zeddies 《Plant Breeding》1994,112(2):110-119
The economic evaluation of forage maize is complex due to its usage in different types of farms as well as the interdependencies of forage maize traits with the farm organization and the intensity of production. By means of linear programming, the economic weights of important forage maize traits were calculated for farming conditions in Germany. They were determined from the difference in the gross margins of farm models for given changes in a single trait of forage maize and were calculated for dairy and bull-fattening farms under five levels of animal performance, three stocking rates, and different levels of forage maize traits. Individual economic weights under these settings varied little in most cases and allowed aggregation of mean economic weights. They amounted to 4.6 ECU ha?1 for metabolizable energy yield (GJ ha?1), 207 ECU ha?1 for metabolizable energy content (MJ kg?1), and 3.1 ECU ha?1 for crude protein content (g kg?1). Economic weight for forage dry matter content was strongly dependent upon the maturity of the materials and varied between -5 and 25 ECU ha?1. The application of economic weights was discussed in comparison with other criteria for the assessment of experimental hybrids in official trials.  相似文献   

19.
×Festulolium ssp. are of particular interest as autumn‐saved herbage in the winter grazing system, but information concerning their performance in this low‐input system is not available. To this end, we examined dry matter (DM) yield and forage quality in winter of four different cultivars of ×Festulolium ssp. (×Festulolium pabulare, Festulolium braunii), either with festucoid or loloid attributes, compared with Festuca arundinacea Schreb. Furthermore, pre‐utilization (accumulation since June or July) and date of winter harvest (December or January) were varied examining the influence of different sward management. DM yield, crude protein, metabolizable energy (ME) (in vitro rumen fermentation technique), acid detergent fibre (ADF) and ergosterol concentration were determined. Within all years, the festucoid cultivars (mean 3.4 t ha?1) attained significant higher yields during winter than the loloid cultivars (mean 1.6 t ha?1), but their yields were comparable with F. arundinacea (mean 3.0 t ha?1). Crude protein was decisively influenced by the different yield levels of the cultivars resulting in higher values for the loloid cultivars. Energy concentrations decreased with later winter harvest, whereas ADF as well as ergosterol concentrations frequently increased from December to January. The greatest differences between festucoid and loloid cultivars were generally observed during severe winters. Obviously, the festucoid cultivars were better adapted to a utilization as autumn‐saved herbage than the cultivars with rather loloid attributes. However, the hybrids did not surpass F. arundinacea regarding yield and quality.  相似文献   

20.
In this study, the effects of nitrogen (N) rate (60, 120, 180 and 240 kg N ha?1 applied in three equal dressings at seeding and after the first and second cuttings) and stubble height (7, 14 and 21 cm) on the dry matter (DM) yield, crude protein (CP) content, and CP yield of a sorghum–sudangrass hybrid [Sorghum bicolor (L.) Moench × Sorghum sudanense (Piper) Stapf., cv. Pioneer 988] in the three‐cut system was investigated. The N rate had no significant effect in the first and third cuttings, but in the second cutting DM yields increased significantly with increase in N rate. The highest yield of 9.1 t ha?1 was obtained with 80 kg N ha?1 for the average of 2 years at the second cutting, but no significant difference was found among the 40, 60 and 80 kg N ha?1 rates. CP content and yield were not significantly affected by N rate at the first and third cuttings, but CP content and yield were significantly affected by application of N at the second cutting. Stubble height had a significant effect on CP content at the third cutting. However, it had no significant effect on CP content at the first and second cuttings. Stubble height had a significant effect on the CP yield at the first cutting, but no significant effect on CP yield at the second and third cuttings.  相似文献   

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