首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   32篇
  免费   0篇
农学   10篇
基础科学   1篇
  15篇
综合类   1篇
农作物   2篇
植物保护   3篇
  2020年   1篇
  2013年   2篇
  2012年   1篇
  2009年   3篇
  2008年   5篇
  2007年   6篇
  2006年   4篇
  2005年   1篇
  2003年   1篇
  2001年   1篇
  1999年   1篇
  1996年   1篇
  1995年   1篇
  1994年   1篇
  1991年   1篇
  1989年   1篇
  1985年   1篇
排序方式: 共有32条查询结果,搜索用时 203 毫秒
1.
Ascochyta blight causes significant yield loss in pulse crops worldwide. Integrated disease management is essential to take advantage of cultivars with partial resistance to this disease. The most effective practices, established by decades of research, use a combination of disease-free seed, destruction or avoidance of inoculum sources, manipulation of sowing dates, seed and foliar fungicides, and cultivars with improved resistance. An understanding of the pathosystems and the inter-relationship between host, pathogen and the environment is essential to be able to make correct decisions for disease control without compromising the agronomic or economic ideal. For individual pathosystems, some components of the integrated management principles may need to be given greater consideration than others. For instance, destruction of infested residue may be incompatible with no or minimum tillage practices, or rotation intervals may need to be extended in environments that slow the speed of residue decomposition. For ascochyta-susceptible chickpeas the use of disease-free seed, or seed treatments, is crucial as seed-borne infection is highly effective as primary inoculum and epidemics develop rapidly from foci in favourable conditions. Implemented fungicide strategies differ according to cultivar resistance and the control efficacy of fungicides, and the effectiveness of genetic resistance varies according to seasonal conditions. Studies are being undertaken to develop advanced decision support tools to assist growers in making more informed decisions regarding fungicide and agronomic practices for disease control.  相似文献   
2.
G. Ladizinsky 《Euphytica》1985,34(2):539-543
Summary Seeds of the cultivated lentil are capable of germinating shortly after maturation. The seed dormancy of wild lentil species is due to a hard seed coat. In crosses between the cultivated species L. culinaris and its wild progenitor L. orientalis the hard seed coat of the wild species was controlled by a single recessive gene in homozygous condition. In a cross between the wild species L. ervoides and L. culinaris the hard seed coat of L. ervoides was controlled by a single dominant gene. The significance of the genetics of seed coat hardness in the domestication of lentil is briefly discussed.  相似文献   
3.
In arid and semi-arid areas of West Asia and North Africa, including the northern Bekaa Valley of Lebanon, farmers have been increasingly practicing continuous barley cultivation. The objectives of the study were to (1) determine whether barley monoculture is unsustainable1, (2) ascertain if barley and total dry matter yields can be increased and sustained by including a legume crop in the rotation, and (3) determine which barley–legume rotations are more productive. The trial was set up in a randomised complete block design with two replicates under rain-fed conditions in 1994–1995 at the Agricultural Research and Educational Center (33°56′ N, 36°5′ E, 995 m above sea level). Eight two-phase barley-based rotations were compared: barley in rotation with barley, lentil, common vetch, bitter vetch, common vetch for grazing, medics for grazing, common vetch for hay, and common vetch with barley for hay. Seed and straw were harvested from barley and legumes in the first four rotations. Relative to the trial mean, seed and straw yield under barley monoculture slumped in 1997–1998 and did not recover since then. Infestation of wild barley was a cause of this yield decline. Barley–legume rotations yielded 44–80% more barley grain and 27–53% more barley straw than the barley monoculture over the 6 years (1995–1996 to 2000–2001). Furthermore, in the legume phase, common and bitter vetch gave higher seed yield than barley monoculture. Thus, all barley–legume rotations, except barley–medics, yielded more total dry matter than barley monoculture on the basis of per rotation cycle. Among the barley–legume rotations, the barley-common vetch for seed rotation gave the highest and most stable dry matter yield. In conclusion, barley monoculture was unsustainable, but barley yields could be increased and sustained by including legumes in the rotation. Farmers in semi-arid areas of Lebanon should discontinue practicing barley monoculture and adopt a barley–legume, such as common vetch, rotation.  相似文献   
4.
Increasing and maintaining crop residues in predominantly cereal-based rotations of the US Pacific Northwest is critical to controlling soil erosion. The core collection of lentil (Lens culinaris Medik.) germplasm comprising 287 accessions was evaluated for variation in phenological, morphological and growth parameters including seed yields and residue amounts over a two-year period under conventional tillage and no-till conditions. The objectives of this study were (i) assess lentil genetic variation in germplasm for variation in biomass production and seed yield, (ii) assess the relationship of phenological and morphological traits with biomass and seed yield and (iii) identify high biomass producing germplasm for use as parents in the breeding program. Days to flowering and days to maturity ranged from 31 to 78 and from 71 to 106 days, respectively. Time to flowering in terms of cumulative heat units was a more efficient measurement than days to flowering. Plant height and plant canopy width had a significant association with total biomass, seed yield and residue amounts. Total biomass ranged from 788–6389 kg ha–1 under conventional tillage, while the range under no-till conditions was 1045–6195 kg ha–1. Most of the lines with higher biomass also produced the highest seed yields and residue amounts. Overall, only one accession produced more residue than `Laird'. In the more favorable environment of 1997, six accessions exceeded the control cultivars, `Laird' and `Indianhead', for residue amounts, and seven and twenty-four accessions exceeded control cultivars, `Pardina' and `Brewer', for seed yield. Results indicated that plant height, canopy width at maturity and seed yield explained most of the variation in biomass and residue production. Large seeded germplasm consistently had a longer reproductive growth period than small seeded accessions and had 17%, 7% and 21% more biomass, seed yield and residue, respectively. Our data indicated significant variation in lentil germplasm for biomass, seed yield and residue amounts to warrant their use in the breeding program.  相似文献   
5.
Lentil anthracnose (Colletotrichum truncatum (Schwein.) Andrus et W.D. Moore is a potential threat in many lentil (Lens culinaris Medik.) production regions of North America. In the lentil germplasm maintained in Germany and North America, 16 lines were reported to have resistance to race Ct1, but none has resistance reported to race Ct0. The objective of this study was to examine accessions of wild Lens species for their resistance to races Ct1 and Ct0 of lentil anthracnose. Five hundred and seventy-four wild accessions of six species and control lines were screened in two replications under both field and greenhouse conditions using a 1–9 scoring scale (1, highly resistant; 2–3, resistant; 4–5, moderately resistant; 6–7, susceptible; and 8–9, highly susceptible). Indianhead and PI 320937 were resistant while Eston and Pardina were susceptible to race Ct1 as expected. However, none of the check lines were resistant to race Ct0. Among the six Lens wild species tested, accessions of Lens ervoides (Brign.) Grande had the highest level of resistance, 3–5 to race Ct1 and Ct0 followed by L. lamottei Czefr. in the field and greenhouse. Lens orientalis (Boiss.), L. odemensis L., L. nigricans (M. Bieb.) Godron and L. tomentosus L. were highly susceptible, 8–9 to race Ct0 in the greenhouse. The highest frequency of resistance, especially in L. ervoides (Brign.) Grande, was found in accessions originating from Syria and Turkey. The usefulness of these L. ervoides (Brign.) Grande accessions as sources of resistance to the more virulent race of anthracnose in a lentil breeding program is discussed.  相似文献   
6.
We studied the dynamics of microbial C, N, and P in soil cropped with rice (Oryza sativa) and lentils (Lens culinaris) in a dryland farming system. The crop biomass and grain yield were also studied. The microbial biomass and its N and P contents were larger under the lentil than under the rice crop. Microbial nutrients decreased as the crops grew and then increased again. Farmyard manure and NPK fertilizer applications increased the level of microbial nutrients, crop biomass, and grain yield by 35–80%, 55–85%, and 74–86%, respectively. However, these applications had no significant effect on most of the soil physicochemical properties in the short term. The microbial biomass was correlated with the crop biomass and grain yield. The calculated flux of N and P through the microbial biomass ranged from 30–45 and 10–19 kg ha-1 year-1, respectively. Cultivation of a cereal crop followed by a leguminous crop sustains higher levels of microbial nutrients and hence greater fertility in impoverished tropical arable soils. The soil microbial biomass appears to contribute significantly to crop productivity by releasing nutrients, and applications of manure, either alone or with fertilizers, promote this effect more strongly than the application of NPK fertilizers alone.  相似文献   
7.
Randomly Amplified Polymorphic DNA markers were used to determine the genetic relationships among Turkish lentil cultivars and breeding lines. Fourteen cultivars and thirteen breeding lines were evaluated to determine genetic variability using nine random 10-mer primers (among 45 primers). Forty-one reproducible bands were obtained, 54% of which were polymorphic. Genetic distances among cultivars and breeding lines were obtained from the simple matching coefficients (SM). The lowest genetic distance was observed between the cultivars of Ali Dayi and Kafkas with 5.0%, while ‘Seyran-96’ and ‘Ozbek’ had the highest genetic distance with 58.3%. An unweighted pair-group method with arithmetic averages (UPGMA) cluster analysis was performed on the distance matrix using Phylip software. The dendrogram clearly showed two distinct groups. The first group is composed of Akm 565 and Akm 563. The second group contains all the cultivars and remaining eleven breeding lines.  相似文献   
8.
A field experiment was conducted at the Division of Agronomy, Indian Agricultural Research Institute, New Delhi during 1983-84 and 1984-85 to study the effect of lentil residues on the yield and response of succeeding rice to nitrogen. Lentil residues benefitted the succeeding rice and gave longer and heavier panicles, more grains per panicle, higher 1000-grain weight and higher grain and straw yield of rice as compared to fallow. Rice responded well to applied nitrogen both in the absence and presence of lentil residues. The effect of lentil root residues and root residues plus incorporation of lentil straw was equivalent to 11 and 33 kg N ha−1 when 60 kg N ha−1 was applied to rice; the corresponding values being 54 and 60 kg N ha−1 when 120 kg N ha−1 was applied to rice.  相似文献   
9.
A sowing date experiment was conducted over 6 years (1978–1983) to determine the optimum sowing date for lentil on vertisols in Debre Zeit area, Ethiopia. The results showed that sowing between the last week of June and the second week of July maximizes lentil yield. Later planting after mid-July, reduced both yield and time to maturity.  相似文献   
10.
Fusarium head blight (FHB) is an important disease which has been causing damage to wheat and barley crops in western Canada. Because crop residues are an important source of inoculum, it is important to know the ability of Fusarium spp. to colonize and survive in different residue types, and how their populations might be affected by agronomic practices. Sampling of residue types on producers’ fields for quantification of Fusarium and other fungi was conducted in 2000–2001 in eastern Saskatchewan. Fusarium spp. were isolated from most fields, whereas their mean percentage isolation (MPI) was over 50% for cereal and pulse residues, and under 30% for oilseed residues. The most common Fusarium, F. avenaceum, had a higher MPI in pulse and flax (45–48%) than in cereal or canola (10–22%) residues. This was followed by F. equiseti, F. acuminatum, F. graminearum, F. culmorum and F. poae which were isolated from all, or most, residue types. Factors affecting Fusarium abundance in residues included the current crop, cropping history, and tillage system. In cereal residues, the MPI of F. avenaceum was higher when the current crop was another cereal (24%) versus a noncereal (4–8%). When the current crop was another cereal, the lowest MPI of F. avenaceum and F. culmorum occurred when the field had been in summerfallow (SF) two years previous (F. avenaceum: 17% for SF, 28% for a crop; F. culmorum: 1% for SF, 4% for a crop); in contrast, F. equiseti and Cochliobolus sativus were most common in residues of cereal crops preceded by SF (F. equiseti: 16% for SF, 10% for a crop; C. sativus: 22% for SF, 13% for a crop). The MPI of F. graminearum was higher when the crop two years previous was an oilseed (7%) versus a cereal (4%). In regards to tillage effects, when the current crop was a cereal, the MPI of F. avenaceum was higher under minimum (MT) and zero tillage (ZT) (22–37%) than conventional tillage (CT) (15%), that of F. graminearum was lowest under ZT (3% for ZT, 7–11% for CT-MT), whereas that of C. sativus was highest under CT (27% for CT, 6–11% for MT-ZT). Under ZT, previous glyphosate applications were correlated positively with F. avenaceum and negatively with F. equiseti and C. sativus. These observations generally agreed with results from previous FHB and root rot studies of wheat and barley in the same region. Percentage isolation of F. avenaceum from noncereal and of F. graminearum from cereal residues were positively correlated with FHB severity and percentage Fusarium-damaged kernels of barley and wheat caused by the same fungi.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号