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1.
Field studies on the nature of competition and the effects of various planting patterns on maize/cowpea intercrop yields were conducted in Southwestern Nigeria. Relative Crowding Coefficient values indicated that maize dominated cowpea. The magnitude of competition between maize and cowpea is related to season and nitrogen fertilizer. Based on grain yields, maize and cowpea compete for N only when it was applied but tended to derive it from different sources in the absence of applied N.
Spatial arrangements designed to increase light reaching intercropped cowpea included alternate and double rows of cowpeas between maize rows. These did not, however, increase grain yields of cowpeas over those intercropped with maize in the same row.  相似文献   

2.
Results reported in the literature with regard to productivity of intercropping systems in comparison to sole cropping are very inconsistent. A field experiment was therefore conducted in the northern part of the Guinea Savanna in Ghana to compare the productivity of maize/cowpea mixed cropping, maize/cowpea relay intercropping with maize/cowpea rotation and maize monocropping over a 4-year period. The treatments included two levels of nitrogen (0 and 80 kg of N ha−1 y −1 as urea) and two levels of phosphorus application (0 and 60 kg of P ha−1 y−1 as Volta phosphate rock). At all levels of N and P application, maize yields of the intercropping systems, especially of maize/cowpea mixed cropping, were significantly lower than in sole cropping. Highest maize yields were obtained in maize/cowpea rotation, which in contrast to the other cropping systems did not show any reductions in yields over years. Cowpea yields were generally less affected by the cropping system, but were notably depressed when cowpea was relay-intercropped with maize. In treatments without fertilizer application (N and P) Land Equivalent Ratios (LER) and Area x Time Equivalency Ratios (ATER) generally indicated lower productivity of the intercropping systems as compared to sole cropping, with the maize/cowpea rotation showing the highest productivity. Conversely, fertilizer application resulted in higher productivity of the intercropping systems over the 4-year period. Productivity on the basis of ATER was generally lowest in maize/cowpea relay-intercropping as a consequence of the long time of land occupation. All of the parameters indicate low productivity of maize monocropping, clearly demonstrating that crop sequence as well as fertilizer application must be considered as important for maintaining high production levels at this site.  相似文献   

3.
Drought is an important yield-reducing factor for corn and soya bean which are the two major crops in the Delaware, Maryland and Virginia (Delmarva) region of the United States. Cowpea (Vigna unguiculata L. Walp.) is primarily grown in drier regions of the world where it is one of the most drought-resistant food legumes. Field experiments were conducted in which 10 genetically diverse cowpea genotypes were evaluated for adaptability to the Delmarva area. The cowpea genotypes were grown in rain-out shelters under non-water-stressed and water-stressed conditions. The results showed that under non-water-stressed conditions cowpea genotypes California Blackeye 5, Champion and Mississippi Silver gave higher seed yields, while genotypes White Acre, Six Week Browneye and Texas Cream 8 provided lower seed yields. Genotypes California Blackeye 5 and Champion gave comparatively better seed yields under water-stressed conditions. California Blackeye 5 was the highest seed-yielding genotype under both water-stressed and non-water-stressed conditions. The highest biological yield under non-water-stressed conditions was given by genotypes Two Crop Brown, White Acre and Elite, whereas under the water-stressed condition genotypes Texas Cream 8, California Blackeye 5, and Mississippi Silver gave higher biological yield. Genotypes Quickpick Pinkeye and Elite were identified as early maturing genotypes. The harvest index (HI) varied significantly among genotypes, with Texas Cream 8 having the lowest HI. Cowpea genotypes which gave higher seed yield under water-stressed conditions could play an important role in sustaining crop production in the Delmarva region.  相似文献   

4.
Cowpea ( Vigna unguiculata L. Walp) is an important food legume grown under rainfed conditions in the tropics. However, the yield of this crop varies widely in most tropical ecosystems due to crop and environmental factors. Experiments were carried out to evaluate the effects of seed characteristics, soil moisture at planting and the season of crop establishment on growth and yield parameters of cowpea as these influence the productivity of the crop. Growth and yield of cowpea plants grown from small seeds with a high conductivity of their lea-chates were significantly lower than those grown from large seeds. Root growth of seedlings was most prominent under moderate soil moisture levels. Low soil moisture retarded root growth by reducing dry weights and suppressing the development of laterals. Shoot growth was more sensitive to increasing soil moisture stress than root growth. Planting cowpea in the wet season produced the highest yields. Within a season, growth and yield were higher when the crop was planted early. Establishment of the crop later in the season produced better quality seeds measured in terms of germination after controlled deterioration.  相似文献   

5.
In a field experiment conducted during 1992–95 at Lucknow, India, sugarcane was planted in rows 60 and 90 cm apart in three crop rotations (rice-sugarcane-ratoon, Sesbania aculeata for green manure-sugarcane-ratoon, and cowpea-sugarcane-ratoon) with 0, 150 and 300 kg N ha−1 as urea either with or without farmyard manure (FYM) at 10 t ha−1. Sugarcane yields were significantly greater in the Sesbania rotation than in the other because of a larger N uptake. N uptake of the crop was significantly affected by soil organic carbon, and available N and K contents. Ratoon yields, however, were largest in the cowpea sequence followed by the rice rotation, probably due to a prolonged residual effect of cowpea and rice root residues. The residual effect of a Sesbania green manure was negligible as demonstrated by the low NO3-N content of the soil profile after sugarcane harvest compared to the other two crop sequences. The total cane productivity (main sugarcane plus ratoon) was greater (156 t ha−1) in the cowpea rotation than the Sesbania (152 t ha−1) and rice (140 t ha−1) rotations.  相似文献   

6.
冯钰  邢宝龙 《作物杂志》2022,38(6):220-49
为筛选出适宜高寒区种植的优质豇豆品种，探究了山西大同高寒区9个豇豆品种的生长特性及饲草品质。结果表明，9个豇豆品种在试验地均能完成生育过程，且作为饲草种植最佳收获期为结荚期。其中以品豇dt2018-5、JD-01和品豇dt2018-9这3个品种表现良好，干物质含量分别为31.9%、35.2%和32.6%，粗蛋白含量分别为22.4%、25.5%和24.2%，粗脂肪含量分别为1.7%、1.4%和1.6%，酸性洗涤纤维含量分别为21.5%、21.2%和24.6%，中性洗涤纤维含量分别为24.5%、27.6%和31.2%，干草产量分别为496、352和325kg/hm2，鲜草产量分别为2661、2241和2132kg/hm2。故品豇dt2018-5、JD-01和品豇dt2018-9可作为推广品种。  相似文献   

7.
Increased yields of some crops have resulted from indirect selection of plant architectural traits related to yield. This study examines the potential relationship between plant architecture and yield for a legume grown under intercropping, Field experiments were conducted in 1991 to examine the response of two cowpea (Vigna unguiculata (L.) Walp.) genotypes with contrasting plant habits to sole crop and intercrop with pearl millet (Pennisetum americanum (L.) Leeke), and to identify cowpea traits associated with yield under intercropping. The cultivur with a bush-type habit was higher-yielding in sole crop, whereas the cultivar with a spreading habit was higher-yielding in intercrop. For F2 cowpea populations, pod number was most highly correlated with seed yield in intercrop. The number of branches and nodes, particularly in areas with increased access to light, and increased internode length were also important in intercrop. Selection for improved yield in sole crop may not necessarily lead to improved yield in intercrop, and different plant traits may be more appropriate for cultivars intended for use in inter-crop than for those intended for use in sole crop.  相似文献   

8.
To compare the feasibilities of pearlmillet-based intercropping systems, field experiments were carried out for 2 years on loamy sand soils in the semi-arid plain zone of Rajasthan, India. Results showed that the pooled yields of pearlmillet from the single crop (1525 kg ha−1) and from the crop intercropped with legumes (1528, 1498 or 1540 kg ha−1) were statistically the same. The yields from intercrop legumes were obtained as a bonus. The highest value of land equivalent ratio (1.21) was recorded for the pearlmillet + clusterbean system, which gave significantly better results than the pearlmillet + cowpea system. It was also found that the dose of nitrogen can be reduced by up to 25 % when pearlmillet is grown with legumes. However, intercrop legumes required the recommended dose of fertilizer to produce their optimal yields. The practice of intercropping without fertilizer proved disadvantageous.  相似文献   

9.
Summary Two breeding procedures were compared in two cowpea crosses. Both procedures were started from the same selected F2 plants in each cross. For the early generation yield testing, the F3 lines were yield tested and a pedigree and bulk methods followed in F4 and F5. Each F5 line was bulked to provide seed for a yield test in F6. In the Single Seed Descent (SSD) procedure, a single seed was taken from each F2 plant to produce the F3 generation. The procedure was repeated for the F4 and F5. The F6 SSD lines and the F6 yield testing lines were compared in yield tests.The results showed that differences in yielding ability of F3 lines persisted over generations indicating that selection was effective. This was confirmed by the high significant correlations between F3 yields and those of later generations which ranged from r=0.51* to 0.85**.The grain yields of lines derived by the single seed descent procedure were as good as those derived from early generation yield testing.Significant linear correlation between visual rating of F3 and F6 yields with actual yields revealed that it is possible to identify promising lines of cowpea visually.  相似文献   

10.
Flower bud thrips, Megalurothrips sjostedti is the most severe field pest of cowpea that causes massive flower abortion which eventually results to substantial yield reduction in Africa. There is paucity of information on the mode of gene actions controlling inheritance of resistance to flower bud thrips in cowpea in the literature. The objectives of study were to assess the genetic variability for thrips resistance among the cowpea germplasm, determined the mode of inheritance of genes that conferred resistance and both broad and narrow-sense heritability estimates for the inheritance of thrips resistance in cowpea. Twelve cowpea lines were used in crosses in the screen house at IITA, Ibadan. The mating was accomplished using North Carolina design II to generate 48F1 hybrids, which were eventually evaluated with the parents. Data on number of peduncles, number of pods and number of thrips per flower were recorded and subjected to analysis of variance using random model by SAS 9.2. Significant variability was observed for most agronomic and thrip-adaptive traits among the cowpea germplasm, parental-lines and F1 genotypes evaluated. General combining ability (GCA) and specific combining ability (SCA) mean squares were significant (P < 0.01) for number of pods per plant and other traits under the research environment. The GCA effect accounted for 68.82–80.07% of the total variation among hybrids for all traits except days to flowering; SCA explained less than 50% of the total variation. Narrow-sense heritability estimates ranged from 7.53 (days to flower) to 63.92% (number of peduncles per plant). Additive gene action largely controlled the inheritance of yield components and other traits under thrips infestation and these traits were moderately heritable.  相似文献   

11.
Productivity of maize ( Zea mays L.) legume intercrops is determined by soil, management, and environment. Planting sequence and time and N fertilization are easily controlled management factors but their effects on intercrop yields are not well understood. Maize grown in monoculture or intercropped with polebean ( Phaseolus vulgaris L.) or cowpea ( Vigna unguiculata [L.] Warp.) was studied for two growing seasons at Morgantown, WV. Crops were seeded in the following sequences: maize before legume, both at the same time, and legume before maize. Planting times were early May or mid June. Nitrogen was applied at 0 or 160 kg ha−1. Maize grain and forage, legume grain and forage, and total forage production were determined on a dry matter basis. Intercropping (average of all treatments) reduced maize grain and forage yields compared to maize in monoculture but had no effect on total forage production. However, total forage production was greatest when the seeding sequence was maize intercropped at the same time or before cowpea. Cowpea never produced grain, but forage production was almost double that of polebean. Maize produced most forage when seeded before the legumes, and the legumes produced most forage when seeded before maize. Early planting increased maize production and decreased legume production. Nitrogen increased maize grain, maize forage, and total forage yields but had not effect on legume forage production. It is concluded that maize/legume intercrops show promise for increasing forage production in temperate areas and more research on planting times and densities, weed control, harvesting and management is needed.  相似文献   

12.
VQ蛋白是一类植物特有的转录调控辅助因子,主要与WRKY蛋白互作,参与诸多生物学功能。尽管一些植物VQ家族基因已经被鉴定,但在豇豆中有关VQ家族基因的研究未见报道。本研究利用生物信息学手段从豇豆中鉴定出37个VuVQ基因,并详细分析这些基因的序列、微共线性、表达谱与进化关系。染色体与共线性分析表明,豇豆VuVQ基因定位在11条染色体上,基因扩增主要由片段重复产生,其中4对重复基因所在区段共线性程度高。序列分析结果显示:豇豆VuVQ基因结构有3种类型,绝大多数无内含子;豇豆VQ蛋白均包含VQ结构域,同时这些VQ保守基序数目和顺序变异较高。进化研究揭示豇豆VQ蛋白存在6大类群,这些类群均起源于陆生植物。选择压力检测表示,豇豆的8对VuVQ基因均受严格的负选择。表达分析表明了豇豆VQ基因具有多样化的表达模式,这意味着VQ蛋白参与多种生物学过程。本研究结果为豇豆VQ基因的功能解析提供线索。  相似文献   

13.
The objective of this work was to evaluate the genetic variability among six cowpea (Vigna unguiculata) cultivars differing in their resistance to Callosobruchus maculatus (F.) weevil. Two resistant bean cultivars were used to compare between the sensitive, moderate tolerant, and high tolerant cowpea cultivars. The differentiations were performed by using random amplified polymorphic DNA (RAPD) fingerprinting, protein concentration and organic and non-organic components in seed coat. Six polymorphic primers were identified, resulting in different informative bands. Based on polymorphic profiles, three clusters were formed. Clustering was mainly affected by the resistance to weevil pest. The sensitive cowpea cultivars were separated in one group, the moderate tolerant and high tolerant cultivars came in separate groups, and finally, the resistant bean cultivars separated clearly in one distinct group. The most interesting result was represented by concentration of total protein in the seed coat. The protein concentration in the resistant bean cultivars were approximately 50% less than concentration in each of the moderate tolerant and sensitive cultivars of cowpea. Ferric ions were about 25% less than the moderate tolerant and sensitive cultivars. The concentrations of calcium and potassium in seed coats were higher in the resistant beans than in cowpea cultivars. Cobalt was about four times higher in resistant bean than in the sensitive and moderate tolerant cowpea cultivars, which may play a major role in seed resistance to weevil.  相似文献   

14.
The effects of variations in the relative sowing time of component crops in okra/maize and okra/cowpea intercropping systems were examined in 1990 and 1991 cropping seasons. Okra was either sown the same day as, or two weeks before or after maize or cowpea. Intercropping reduced the growth and yield of okra, maize and cowpea relative to their sole crops. However, okra yield was depressed more by maize than by cowpea, especially when okra was sown two weeks after maize. Comparative assessment of okra/maize and okra/cowpea mixtures suggests that it is better to grow okra and cowpea together than intercropping okra and maize because yield advantages were always higher in okra/cowpea (67% and 59% in 1990 and 1991 respectively) than in okra/maize (15% and 29%). The results were discussed in light of competitive abilities of the various components in the mixtures.  相似文献   

15.
Degenerate oligonucleotides designed to recognize conserved coding regions within the nucleotide binding site (NBS) and hydrophobic region of known resistance (R)genes from various plant species were used to target PCR to amplify resistance gene analogs (RGAs) from a cowpea (Vigna unguiculata L. Walp.) cultivar resistant to Striga gesnerioides. PCR products consisted of a group of fragments approximately 500 bp in length that migrated as a single band during agarose gel electrophoresis. The nucleotide sequence of fifty different cloned fragments was determined and their predicted amino acid sequences compared to each other and to the amino acid sequence encoded by known resistance genes, and RGAs from other plant species. Cluster analysis identified five different classes of RGAs in cowpea. Gel blot analysis revealed that each class recognized a different subset of loci in the cowpea genome. Several of the RGAs were associated with restriction fragment length polymorphisms, which allowed them to be placed on the cowpea genomic map. The potential for using these sequences to isolate R genes, and subsequent direct manipulation of disease and pest resistance using genetic engineering is discussed. This revised version was published online in August 2006 with corrections to the Cover Date.  相似文献   

16.
Cowpea (Vigna unguiculata (L.) Walp) is a legume of economic importance world-wide, especially in Western Africa, where it is an important part of the population’s diet. The rapidly increasing population growth in Africa requires substantial increase in cowpea production, which can be achieved by expanding land areas for agricultural purposes. In addition, prevalence of soil acidity in Africa constrains such an alternative since phosphorus availability, a key element for plant growth and development, is limited, thus resulting in poor cowpea production. The objectives of this study were to conduct an association analysis for adaptation to low phosphorus conditions and rock phosphate response in cowpea, and to identify SNP markers associated with these two traits. A total of 357 cowpea accessions, collected worldwide, was evaluated for phosphorus stress and response to addition of rock phosphate. Association analysis was conducted using 1018 SNPs obtained using genotyping-by-sequencing (GBS). TASSEL 5 and R were used for association mapping studies based on six different models. The results indicated that: (1) substantial variability in adaptation to low phosphorus conditions and rock phosphate response exists in the USDA cowpea accession panel; (2) ten SNP markers, C35006753_110, C35028233_482, C35072764_1384, C35084634_455, Scaffold21750_4938, Scaffold26894_5408, Scaffold41885_14420, Scaffold45170_4650, Scaffold50732_679; and Scaffold88448_741 were found to be associated with tolerance to low phosphorus conditions in cowpea, and (3) eight SNP markers, C35028233_482, C35058535_121, Scaffold26894_5408, Scaffold45170_4650, Scaffold51609_507, Scaffold53730_7339, Scaffold74389_5733, and Scaffold87916_4921 were highly associated with rock phosphate response. These SNP markers can be used in a marker-assisted breeding (MAS) program to improve cowpea tolerance to phosphorus stress.  相似文献   

17.
Lemongrass ( Cymbopogon flexuosus (Steud.) Wats) is a perennial, multicut aromatic grass, which yields an essential oil used in perfumery and pharmaceutical industries and Vitamin A, has a long initial lag phase. To utilize the crop growth resources more efficiently during this phase, studies were made to explore the possibility of intercropping food legumes with lemongrass. An experiment conducted during 1992–93 revealed that the food legumes like blackgram ( Vigna mungo (L) Hepper), cowpea ( Vigna unguiculata (L) Walp) or soybean ( Glycine max (L) Merr.) could be intercropped in the initial stages of lemongrass to get extra yields over and above that of lemongrass, without affecting the yield of lemongrass.  相似文献   

18.
豇豆蓟马发生规律及防治药剂筛选的研究   总被引：1，自引：0，他引：1  
为探明在冬种豇豆的整个生育期内,为害豇豆的蓟马种类及各种蓟马的种群消长情况,于2014—2016年在海南三亚开展了冬种豇豆的蓟马种类和数量的调查。结果表明:为害豇豆的蓟马有4种,即豆大蓟马、花蓟马、棕榈蓟马和黄胸蓟马;其中,豆大蓟马与棕榈蓟马在豇豆的整个生育期内均可为害,花蓟马与黄胸蓟马仅在花期发生。豆大蓟马为豇豆蓟马的优势种,其发生高峰期在豇豆的盛花期;其次是花蓟马,其数量在豇豆生长后期逐渐增加;棕榈蓟马的数量在豇豆花期虽有所增加,但始终维持在较低水平;黄胸蓟马仅偶尔出现,且数量极少。为了解新型杀虫剂对豇豆蓟马的防效,采用喷雾法,开展了豇豆蓟马的田间药效试验。试验结果表明:在参试的5种新型药剂中,乙基多杀菌素和苦参碱对豇豆蓟马具有较好的防效,药后3天防效分别为79.14%和62.14%,高于对照药剂啶虫脒的防效。药后7天,所有参试药剂对豇豆蓟马的防效均不理想,除了乙基多杀菌素,其余药剂防效均小于50%。在参试的药剂中,乙基多杀菌素、苦参碱对豇豆蓟马具有较好的防效,可以与啶虫脒轮换使用,用于豇豆蓟马的田间防治。  相似文献   

19.
N. Thurling  M. Ratinam 《Euphytica》1987,36(3):913-926
Summary The mean aim of this study was to identify an effective method of predicting cross-potential in respect of yield improvement of the cowpea (Vigna unguiculata (L.) Walp.) through hybridization and subsequent selection.Three prediction tests based on data collected from experiments with ten cowpea lines and the F1 and F2 generations of all possible crosses between these lines were evaluated. The three prediction tests were based on: i Yields of prospective parents. ii. General combining abilities estimated from F1 and parental data iii. Frequencies of superior plants in F2 populationsEach of the three procedures was used to identify the crosses with the lowest or highest yield potential, i.e. those crosses most likely to produce the greatest number of lines with yields higher or lower than those of either parent. Crosses selected on the basis of these criteria were evaluated in the following growing season on the basis of biometrical analysis of F2 and backcross populations and the performance of the respective F3 and F4 generations.Six different crosses were selected from the 45 tested on the basis of the three prediction tests. Analyses of F2 and backeross populations from each cross provided estimates of [d] the difference in parental means and 1/2D the additive genetic component which, in turn, were used to predict the frequency of transgressive inbred lines obtained by single-seed descent from the F2. Both crosses selected on the basis of F2 data were expected to produce a much higher frequency of transgressive lines than those selected on the basis of parental yields. The high potential cross selected on the basis of general combining ability was expected to produce a higher frequency of transgressive lines than the corresponding low yield potential cross. Replicated trails of F3 bulks of the selected crosses showed that high yield potential crosses were significantly higher yielding than low yield potential crosses for all prediction criteria. In a trial with 22F4 lines of each of the two crosses selected on the basis of parental yields and frequency of high yielding F2 plants, the high yield potential cross in each case had a greater mean and variance for seed yield than the corresponding low yield potential cross.It was concluded that parental yields provide a sound basis for an initial screening of prospective parents. This screening should identify a high yielding line which can be crossed with a number of contrasting lines to produce F2 populations for the final screening phase.  相似文献   

20.
Leaf extracts and mulch from 14 MPTs were used to study their effects on germination, initial growth and nodulation of cowpea. Aqueous leaf extracts of , , and full concentrations were added to cowpea seeds placed in Petri dishes. In the pot experiment, cowpea was planted in plastic pots filled with 1200 g of soil, and mulch was either surface-applied or incorporated into the substrate at rates equivalent to 5, 10 and 20 tons · ha−1. Leaf extracts from Gliricidia sepium, Senna siamea, Milletia thoningii, Grewia pubescens and Tetrapleura tetraptera reduced cowpea germination significantly at concentrations above 25 % of the full concentration 7 days of incubation. Root length was also strongly reduced by extracts from Gmelina arborea, Senna siamea, Alchornea coordifolia, and Tetrapleura tetraptera. These inhibiting effects were also observed in the pots. Mulch incorporation significantly reduced growth and nodulation of cowpea in the pots. These reductions were more pronounced with the incorporation of mulch from fast decomposing trees such as Leucaena leococephala, Gliricidia sepium and Grewia pubescens. Although Leucaena leucocephala and Gliricidia sepium released much nitrogen, they strongly reduced cowpea growth when incorporated. This may suggest that other reasons than N immobilization caused growth reduction when the plant residues were applied to cowpea.  相似文献   

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