species are the most detrimental pathogens of soybean root rot worldwide, causing large loss in soybean production. Maize/soybean relay strip intercropping has significant advantages on the increase ...of crop yields and efficient use of agricultural resources, but its effects on the occurrence and pathogen population of soybean root rot are rarely known. In this study, root rot was investigated in the fields of the continuous maize/soybean strip relay intercropping and soybean monoculture.
species were isolated from diseased soybean roots and identified based on sequence analysis of translation elongation factor 1 (
1
and RNA polymerase II second largest subunit (RPB2), and the diversity and pathogenicity of these species were also analyzed. Our results showed that intercropping significantly decreased soybean root rot over monoculture. A more diverse Fusarium population including
species complex (FSSC),
species complex (FIESC),
,
,
,
and
was identified from intercropping while FSSC, FIESC,
,
,
and
were found from monoculture. All
species caused soybean root infection but exhibited distinct aggressiveness. The most aggressive
.
was more frequently isolated in monoculture than intercropping. FSSC and FIESC were the dominant species complex and differed in their aggressiveness. Additionally,
,
were specifically identified from intercropping with weak or middle aggressiveness. Except for
,
and
were firstly reported to cause soybean root rot in China. This study indicates maize/soybean relay strip intercropping can reduce soybean root rot, change the diversity and aggressiveness of
species, which provides an important reference for effective management of this disease.
Planting arrangements affect radiation use efficiency (RUE) and competitiveness of intercrop species in intercropping systems. Here, we reveal that narrow‐wide‐row planting arrangement in ...maize‐soybean relay‐intercropping system increases the dry matter and competitiveness of soybean, increased the RUE of maize and soybean, and compensates the yield loss of maize by substantially increasing the yield of soybean. In this field study, maize was planted with soybean in different planting arrangements (P1, 20:180, P2, 40:160; P3, 60:140, and P4, 80:120) of relay intercropping, all the relay‐intercropping treatments were compared with sole crops of maize (SM) and soybean (SS). Results showed that P1 improved the total RUE 3.26 g/MJ (maize RUE + soybean RUE) of maize and soybean in relay‐intercropping system. Compared to P4, treatment P1 increased the soybean competition ratio (CR) values (by 55%) but reduced the maize CR values (by 29%), which in turn significantly improved the yield of soybean by maintaining the maize yield. Generally, in P1, soybean produced 82% of SS yield, and maize produced 88% of SM yield, and it achieved the land equivalent ratio of 1.7. These results suggest that by maintaining the appropriate planting distances between maize and soybean we can improve the competitiveness and yield of intercrop species in relay‐intercropping system.
Here, we reveal that narrow‐wide‐row planting arrangement in relay‐intercropping system increased the dry matter production and competitiveness of soybean plants, enhanced the RUE of intercrop‐species, and compensates the slight maize yield loss by considerably increasing the soybean yield.
Maize-soybean relay-intercropping (MS
) is a famous system of crop production in developing countries. However, maize shading under this system directly affects the light quality and intensity of ...soybean canopy. This is a challenging scenario in which to implement the MS
system, in terms of varieties selection, planting pattern, and crop management since the duration of crop resource utilization clearly differs.
Therefore, this experiment aimed to elucidate the effect of leaf excising treatments from maize top to fully clarify the needs and balance of light quality and intensity of intercrop-soybean under MS
in field conditions. The effects of different leaf excising treatments (T0, no removal of leaves; T2, removal of two topmost leaves; T4, removal of four topmost leaves; T6, removal of six topmost leaves from maize plants were applied at first-trifoliate stage (V
) of soybean) on photosynthetically active radiation transmittance (PAR
), red to far-red ratio (R:FR), morphological and photosynthetic characteristics and total biomass production at second-trifoliate stage (V
), fifth-trifoliate stage (V
), and flowering-stage (R
) of soybean were investigated through field experiments for 2-years under MS
.
As compared to T0, treatment T6 increased the PAR
and R:FR ratio at soybean canopy by 77% and 37% (V
), 70% and 34% (V
), and 41% and 36% (R
), respectively. This improved light environment in T6 considerably enhanced the leaf area index, SPAD values and photosynthetic rate of soybean plants by 66%, 25% and 49% at R
, respectively than T0. Similarly, relative to control, T6 also increased the stem diameter (by 29%) but decreased the plant height (by 23%) which in turn significantly increased stem breaking strength (by 87%) by reducing the lodging rate (by 59%) of soybean plants. Overall, under T6, relay-cropped soybean produced 78% of sole soybean seed-yield, and relay-cropped maize produced 81% of sole maize seed-yield. Our findings implied that by maintaining the optimum level of PAR
(from 60% to 80%) and R:FR ratio (0.9 to 1.1), we can improve morphological and photosynthetic characteristics of soybean plants in MS
. Therefore, more attention should be paid to the light environment when considering the sustainability of MS
via appropriate planting pattern selection.
Strip width management is a critical factor for producing higher crop yields in relay intercropping systems. A 2‐year field experiment was carried out during 2012 and 2013 to evaluate the effects of ...different strip width treatments on dry‐matter production, major‐nutrient (nitrogen, phosphorus, and potassium) uptake, and competition parameters of soybean and maize in relay intercropping system. The strip width (SW) treatments were 0.40, 0.40, and 0.40 m (SW1); 0.40, 0.40, and 0.50 m (SW2); 0.40, 0.40, and 0.60 m (SW3); and 0.40, 0.40, and 0.70 m (SW4) for soybean row spacing, maize row spacing, and spacing between soybean and maize rows, respectively. As compared to sole maize (SM) and sole soybean (SS), relay‐intercropped maize and soybean accumulated lower quantities of nitrogen, phosphorus, and potassium in all treatments. However, maize in SW1 accumulated higher nitrogen, phosphorus, and potassium than SW4 (9%, 9%, and 8% for nitrogen, phosphorus, and potassium, respectively). Soybean in SW3 accumulated 25% higher nitrogen, 33% higher phosphorus, and 24% higher potassium than in SW1. The improved nutrient accumulation in SW3 significantly increased the soybean dry matter by 19%, but slightly decreased the maize dry matter by 6% compared to SW1. Similarly, SW3 increased the competition ratio value of soybean (by 151%), but it reduced the competition ratio value of maize (by 171%) compared to SW1. On average, in SW3, relay‐cropped soybean produced 84% of SS seed yield and maize produced 98% of SM seed yield and achieved the land equivalent ratio of 1.8, demonstrating the highest level in the world. Overall, these results suggested that by selecting the appropriate strip width (SW3; 0.40 m for soybean row spacing, 0.40 m maize row spacing, and 0.60 m spacing between soybean and maize rows), we can increase the nutrient uptake (especially nitrogen, phosphorus, and potassium), dry‐matter accumulation, and seed yields of relay‐intercrop species under relay intercropping systems.
Strip width management is a critical factor for producing higher crop yields in relay intercropping systems. Results of this study suggested that by selecting the appropriate strip width, we can increase the nutrient uptake (especially nitrogen, phosphorus, and potassium), dry matter accumulation, and seed yields of relay‐intercrop species under relay intercropping systems.
The dynamic of soil-borne disease is closely related to the rhizosphere microbial communities. Maize-soybean relay strip intercropping has been shown to significantly control the type of soybean root ...rot that tends to occur in monoculture. However, it is still unknown whether the rhizosphere microbial community participates in the regulation of intercropped soybean root rot. In this study, rhizosphere
and
communities were compared in either healthy or root-rotted rhizosphere soil from monocultured and intercropped soybean, and our results showed the abundance of rhizosphere
in intercropping was remarkably different from monoculture. Of four species identified,
was the most aggressive and more frequently isolated in diseased soil of monoculture. In contrast,
was largely accumulated in healthy rhizosphere soil of intercropping rather than monoculture.
dramatically increased in the rhizosphere of intercropping, while
and
also exhibited distinct isolation frequency. For the antagonism test in vitro,
strains had antagonistic effects on
with the percentage of mycelial inhibition ranging from 50.59-92.94%, and they displayed good mycoparasitic abilities against
through coiling around and entering into the hyphae, expanding along the cell-cell lumen and even dissolving cell walls of the target fungus. These results indicate maize-soybean relay strip intercropping significantly increases the density and composition proportion of beneficial
to antagonize the pathogenic
species in rhizosphere, thus potentially contributing to the suppression of soybean root rot under the intercropping.
Maize/soybean relay strip intercropping has been widely practiced in Southwest China due to its high productivity and effective application of agricultural resources; however, several seedborne ...diseases such as seedling blight, pod and seed decay are frequently observed causing severe yield loss and low seed quality. So far, the population and pathogenicity of the seedborne fungi associated with intercropped soybean remain unexplored. In this study, seeds of 12 soybean cultivars screened for intercropping were collected from three growing regions in Sichuan Province of Southwest China, and the seedborne fungi were isolated from the surface-sterilized seeds. Based on sequence analysis of ribosomal DNA internal transcribed spacer (rDNA ITS), 148 isolates were identified into 13 fungal genera, among which Fusarium covered 55.0% as the biggest population followed by Colletotrichum. Furthermore, Fusarium isolates were classified into five distinct species comprising F. fujikuroi, F. proliferatum, F. verticillioides, F. asiaticum and F. incarnatum through sequence analysis of translation elongation factor 1 alpha (EF-1α) and DNA-directed RNA ploymerase II second largest subunit (RPB2). Among them, F. fujikuroi accounted for 51.22% (42/82) and was isolated from 91.7% (11/12) soybean varieties. Pathogenicity assay showed that five Fusarium species were able to infect the seeds of soybean cultivar “Nandou12” and caused water-soaked or rot symptoms, while F. fujikuroi and F. asiaticum had much higher aggressiveness than other species with significant reductions of seed fresh weight and germination percentage. Accordingly, this study indicates that Fusarium species are the dominant seedborne fungi in the intercropped soybean in Sichuan, China, and this provides some useful references for the effective management of seedborne fungal diseases as well as soybean resistance breeding in maize/soybean relay strip intercropping.
Common carp
was introduced from Thailand to Pakistan in 1964 for the purpose of aquaculture. Due to its high tolerance to temperature and turbidity, and prolific pond breeding habit, it was ...established promptly in most of natural inland waters, including rivers, lakes, streams, canals, wetlands and even village ponds of the country. Although common carp became one of the most abundant cyprinid species in inland waters and important food fish in Pakistan, its impact is not well documented. Fish farming of common carp has been carried out in Pakistan since 1970; initially it grew slowly but now it is playing an important role in the economy of the country by employing more than 400,000 people. Nowadays, farming of freshwater carps is present throughout Pakistan, especially in the provinces of Punjab and Sindh. There is a huge potential in common carp farming and it could help increase the livelihood of people and gross domestic product (GDP) of the country as well. Still, there is a need to improve the fish farming practice to meet the world-class demands that could only be possible by the keen interest of policy makers and stake holders with better management.
Fusarium graminearum is the most devastating pathogen of Fusarium head blight of cereals, stalk and ear of maize, and it has recently become a potential threat for soybean as maize-soybean strip ...relay intercropping is widely practiced in China. To elucidate the pathogenesis mechanism of F. graminearum on intercropped soybean which causes root rot, transcriptional profiling of F. graminearum at 12, 24, and 48 h post-inoculation (hpi) on soybean hypocotyl tissues was conducted. In total, 2313 differentially expressed genes (DEGs) of F. graminearum were annotated by both KEGG pathway and Gene Ontology (GO) analysis. Among them, 128 DEGs were commonly expressed at three inoculation time points while the maximum DEGs were induced at 24 hpi. In addition, DEGs were also rich in carbon metabolism, ribosome and peroxisome pathways which might contribute to carbon source utilization, sexual reproduction, virulence and survival of F. graminearum when infected on soybean. Hence, this study will provide some basis for the deep understanding the pathogenesis mechanism of F. graminearum on different hosts and its effective control in maize-soybean strip relay intercropping systems.
Intercropping has been considered as a kind of a sustainable agricultural cropping system. In southwest China, maize/soybean strip intercropping has commonly been practised under local limited ...agricultural land resources. However, heavy rainfall in combination with high humidity and low temperatures cause severe pod and seed deterioration in the maturity and pre-harvesting stages of intercropped soybean. Numerous
species have been reported as the dominant pathogens of soybean root rot, seedling blight, as well as pod field mold in this area. However, the diversity and pathogenicity of
species on soybean pods remain unclear. In the current study, diseased soybean pods were collected during the cropping season of 2018 from five different intercropped soybean producing areas. A total of 83 F
isolates were isolated and identified as
. f
, and
equiseti species complex based on morphological characteristics and phylogenetic analysis of the nucleotide sequence of EF1-α and
PB2 genes. Pathogenicity tests demonstrated that all F
species were pathogenic to seeds of the intercropped soybean cultivar Nandou12.
usarium
had the maximum disease severity, with a significant reduction of seed germination rate, root length, and seed weight, followed by F.
e
, F.
, F.
and F. incarnatum. Additionally, the diversity of Fusarium species on soybean pods was also considerably distinct according to the geographical origin and soybean varieties. Thus, the findings of the current study will be helpful for the management and resistance breeding of soybean pod decay in the maize/soybean intercropping system.
•A multiplex RT-PCR assay for the simultaneous detection of soybean mosaic virus, bean common mosaic virus and cucumber mosaic virus was developed.•Parameters, including annealing temperature, ...extension time, number of cycles, and primer type and concentration, were optimised.•The multiplex RT-PCR was highly sensitive, rapid and simple, and was evaluated using field samples of soybean plants infected with these viruses.
Soybean is susceptible to viral diseases which are often present as mixed infections. The individual simplex RT-PCR methods used for the identification of multiple viruses are more tedious and time-consuming than the corresponding multiplex RT-PCR. This study used soybean mosaic virus (SMV), bean common mosaic virus (BCMV) and cucumber mosaic virus (CMV)-infected leaf samples from southern China as the test materials to evaluate a multiplex RT-PCR assay developed for the simultaneous detection of these viruses. The parameters optimised included the annealing temperature, extension time, number of cycles, and primer type and concentration. The specific fragments sizes obtained by the multiplex RT-PCR were 550 bp (SMV), 288 bp (BCMV) and 99 bp (CMV). The assay was tested using infected soybean samples obtained from farmers’ fields in Sichuan Province, China. The multiplex RT-PCR assay had high sensitivity, was rapid and simple, and could be used for the diagnosis of soybean infected with various combinations of these viruses in the field.
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