QTL mapping of seedling biomass and root traits under different nitrogen conditions in bread wheat(Triticum aestivum L.)

Plant nitrogen assimilation and use efficiency in the seedling's root system are beneficial for adult plants in field condition for yield enhancement. Identification of the genetic basis between root traits and N uptake plays a crucial role in wheat breeding. In the present study, 198 doubled haploid lines from the cross of Yangmai 16/Zhongmai 895 were used to identify quantitative trait loci(QTLs) underpinning four seedling biomass traits and five root system architecture(RSA) related traits. The plants were grown under hydroponic conditions with control, low and high N treatments(Ca(NO_3)_2·4H_2 O at 0, 0.05 and 2.0 mmol L~(-1), respectively). Significant variations among the treatments and genotypes, and positive correlations between seedling biomass and RSA traits(r=0.20 to 0.98) were observed. Inclusive composite interval mapping based on a high-density map from the Wheat 660 K single nucleotide polymorphisms(SNP) array identified 51 QTLs from the three N treatments. Twelve new QTLs detected on chromosomes 1 AL(1) in the control, 1 DS(2) in high N treatment, 4 BL(5) in low and high N treatments, and 7 DS(3) and 7 DL(1) in low N treatments, are first reported in influencing the root and biomass related traits for N uptake. The most stable QTLs(RRS.caas-4 DS) on chromosome 4 DS, which were related to ratio of root to shoot dry weight trait, was in close proximity of the Rht-D1 gene, and it showed high phenotypic effects, explaining 13.1% of the phenotypic variance. Twenty-eight QTLs were clustered in 12 genetic regions. SNP markers tightly linked to two important QTLs clusters C10 and C11 on chromosomes 6 BL and 7 BL were converted to kompetitive allele-specific PCR(KASP) assays that underpin important traits in root development, including root dry weight, root surface area and shoot dry weight. These QTLs, clusters and KASP assays can greatly improve the efficiency of selection for root traits in wheat breeding programmes.     

氮肥配施下不同C/N作物残渣还田对红壤温室气体排放的影响

氮肥配施能够促进还田秸秆的分解,为了解其对不同C/N秸秆还田下温室气体排放的影响,采用培养实验方法,研究了油菜饼(C/N为4)、玉米秸秆(C/N为28)、水稻秸秆(C/N为41)和小麦秸秆(C/N为71)等4种不同C/N植物残渣在不同量氮肥(无氮、低氮和高氮)配施下对红壤温室气体(CO2、CH4和N2O)排放的影响。结果显示,氮肥配施增加了不同植物残渣的CO2-C累积排放量,且仅在高C/N的小麦秸秆处理中发现存在显著性差异,在低氮和高氮下CO2-C累积排放量分别达到1 271.44、1 212.83 mg·kg-1,显著高于无氮肥配施的883.40 mg·kg-1。土壤N2O累积排放量最大的为油菜饼处理组,低氮量的配施进一步增强了N2O的产生,其累积排放量达到5 550.42μg·kg-1,显著高于无氮肥配施的4 430.44μg·kg-1,然而当氮肥施用量进一步增加时却抑制了N2O的排放(3752.84μg·kg-1)。氮肥配施并未显著影响玉米秸秆和小麦秸秆处理组的N2O累积排放量。在培养期内,每一个处理均表现为CH4的吸收现象,氮肥施用能够增加土壤对CH4的累积吸收量,但差异显著性仅在对照和油菜饼处理中发现。     

Versatile physiological functions of the Nudix hydrolase family in berry development and stress response in grapevine

Nudix hydrolases are widely distributed across all classes of organisms and provide the potential capacity to hydrolyze a wide range of organic pyrophosphates. Although Nudix hydrolases are involved in plant detoxification processes in response to abiotic and biotic stresses, the biological functions of Nudix hydrolases remain largely unclear in grapevine.In the present study, a total of 25 putative grapevine Nudix hydrolases(VvNUDXs) were identified by bioinformatics analysis and classified int...     

Soil available potassium affected by rice straw incorporation and potassium fertilizer application under a rice–oilseed rape rotation system

Data from 147 field trials were collected to study the influence of straw incorporation on soil potassium (K) under an intensive rice–oilseed rape rotation system, while pot experiments were conducted to evaluate the effects of rice straw incorporation on soil K availability. A significant correlation was observed between the soil available K and the relative yield (RRY) and the relative K uptake (RKU) of oilseed rape, with R² values ranging from 0.07 to 0.08 and from 0.10 to 0.11, respectively, when data were fitted to a logarithmic equation model. In approximately 30% of trials, RRY reached 90%, while soil test available K values were below the critical limit, indicating that soil K values at the time of sampling (within 1 week of rice harvest) underestimated the actual soil K supply capacity. The pot experiment results showed that soil available K was affected by straw incorporation and soil type in the fallow period. The NH₄OAc‐K and NaBPh₄‐K concentrations of soils increased at first, and then, plateaued after 28 days. Straw incorporation significantly influenced the critical soil K concentration, which is important for making accurate K fertilizer recommendation. These results suggested that straw K should be seriously considered in making K fertilizer recommendations. Extending the sampling time from 1 to 3 weeks after the harvesting of rice to stabilize the effects of straw incorporation may help achieve a more accurate evaluation of soil available K.     

REVIEW: Properties of Cereal Brans: A Review

Cereal brans are functional ingredients with high nutritive value and enormous health properties. Cereal brans have not been fully utilized in food systems despite their health benefits. This review presents an overview on the physical, chemical, microbiological, functional, and sensory properties of cereal brans for possible comparisons and selection to enhance the utilization of this underutilized milling fraction.     

Application and mechanisms of metal-based nanoparticles in the control of bacterial and fungal crop diseases

Nanotechnology is a young branch of the discipline generated by nanomaterials. Its development has greatly contributed to technological progress and product innovation in the field of agriculture. The antimicrobial properties of nanoparticles (NPs) can be used to develop nanopesticides for plant protection. Plant diseases caused by bacterial and fungal infestations are the main types of crop diseases. Once infected, they will seriously threaten crop growth, reduce yield and quality, and affect food safety, posing a health risk to humans. We reviewed the application of metal-based nanoparticles in inhibiting plant pathogenic bacteria and fungi, and discuss the antibacterial mechanisms of metal-based nanoparticles from two aspects: the direct interaction between nanoparticles and pathogens, and the indirect effects of inducing plant resilience to disease. © 2022 Society of Chemical Industry.     

Towards developing resistance to chickpea chlorotic dwarf virus through CRISPR/Cas9-mediated gene editing using multiplexed gRNAs

Journal of Plant Diseases and Protection - Mastreviruses are an emerging group of viruses transmitted by leafhoppers and infect both monocot and dicot plants. Chickpea chlorotic dwarf virus...     

Hydraulic model investigation of downstream erosion of large regulators: a case study

Flow conditions, which could not be explained, occurred in the stilling basin and outfall channel of the Feni Regulator sited at the western end of the Feni River closure dam. This regulator controls outflows from the upstream reservoir which supplies irrigation water to Muhuri Project in Bangladesh. Analysis of flood discharge data revealed that the design discharge for the structure was not exceeded; yet abnormal scour occurred in the outfall channel and the brick block rip-rap placed thereon was damaged. A model study was conducted to understand the causes of such unusual local erosion downstream of the stilling basin and to provide answers to two main questions:

-Is potential scour serious in terms of the stability of the structure?

-What protection measures could be taken to stabilize the scour at a safe level?

Using a 1:30 scale model, the probable maximum scour was simulated, and the performance of alternative rip-rap designs including that of the existing one were examined. The results of this study supplemented by field scour data collected during subsequent flood seasons indicated that even if the flow rate through the regulator approaches the design flood discharge, the downstream scour is not likely to extend up to an elevation of ? 10.7 m, a scour level observed in the previous year at a lower discharge. It also showed that the existing rip-rap blocks were marginally undersized and consequently the rip-rap was prone to failure if flow conditions departed from uniform. A suitable method of scour protection downstream of the stilling basin at the regulator exit also evolved from the study.