Annals of Applied Biology最新文献

Effective matching between the heat demand of maize varieties and regional resources is essential for achieving high yields. To evaluate the effects of planting density and variety allocation on maize yield and resource utilization efficiency in the different agroecological zones of southwest China, we conducted experiments in five agroecological zones in Guizhou Province. When comparing the same planting density at different sites, grain yield and dry matter accumulation decreased in the following order: Weining, Bijie > Tongren > Anshun and Xingren. Jinyu 838 and Xingzhongyu 801 had a higher yield (12.91 and 12.86 t ha⁻¹) at 82500 plants ha⁻¹ at Weining. The production efficiency for effective accumulated temperature (g m⁻² [°C·day]⁻¹) at Weining was higher than that at the other sites. However, the production efficiency for cumulative solar radiation (g MJ⁻¹) at Weining was lower than that at the Anshun and Tongren sites. Moreover, grain yield and dry matter accumulation were positively correlated with the diurnal temperature range, accumulated solar radiation, and number of growing days. Therefore, by optimizing variety and planting density, maize yield and resource utilization efficiency can be improved in areas with large diurnal temperature and high accumulated solar radiation in southwest China.

Plant pathogens can cause significant losses in plant production. To address this issue, it is crucial to develop innovative technologies that promote sustainability in production. One potential solution is the use of plant growth-promoting microorganisms, particularly those with biocontrol properties. In this study, root-endophytic actinomycetes isolated from Bromus auleticus, a South American forage grass, were investigated. Their ability to promote plant growth and their biocontrol activity against fungal phytopathogens were analysed. The actinomycetes were characterised molecularly, morphologically, and physiologically. Their ability to solubilise P, fixate N₂, produce phytohormones, nitrate, siderophores, phenazines and lytic enzymes was assessed. Both in vitro dual-antagonistic and in vivo biocontrol assays were performed. The strains were identified as species of the Micromonospora and Microbispora genus. They were able to produce auxins, solubilise phosphorus and release lytic enzymes, and nitrate. In vitro, both species of Micromonospora aff. halotolerans reduced the growth of fungal phytopathogens by 12%–34%. In particular, the strain Micromonospora aff. halotolerans TWB21 was found to reduce the pre-emergence effects of Fusarium oxysporum growth when the actinomycete was inoculated by seed immersion. Moreover, this strain improved the seed emergence, plant establishment and plant growth parameters under biotic stress. These results remark the importance of endophytic actinomycetes with biocontrol and plant growth-promoting abilities in enhancing their host establishment and biomass production. This reinforces the idea that Micromonospora strains could be applied as biocontrol agents on grasses with agronomic interest.

Laboratory and pot trials were conducted to study germination performance of rapeseed (Brassica napus L., genotype Excalibur) under NaCl salinity after seed priming with 20 mM NaCl for 24 h. In the laboratory trial, salinity levels of 80, 160, and 240 mM NaCl reduced the germination percentage by 14, 56, and 80 percentage points, respectively compared to the non-saline control. NaCl priming lowered the detrimental effect of salt stress on germination by promoting germination from 81% to 85% under salinity of 80 mM, from 39% to 68% under salinity of 160 mM, and from 15% to 56% under salinity of 240 mM NaCl (maximum alleviation). Furthermore, NaCl priming increased the germination tolerance index and the vigour index of seedlings as compared with the control seeds. Relative water content of the leaves was decreased with increasing salinity, showing limited water availability and a loss of turgor in the leaves. NaCl priming reduced the decrease in relative water content under salinity. Concerning the pot trial, the salinity level of 240 mM NaCl reduced the dry weight of rapeseed seedlings by 80.9% in the non-primed seeds and by 55.8% in the primed seeds. NaCl priming improved the mean productivity index by 1.26 times under salinity of 240 mM NaCl and the harmonic mean index by 1.98 times under salinity of 240 mM NaCl compared with non-primed seeds. Salinity limited seed performance of rapeseed, whereas NaCl priming improved seed performance and early growth in saline environment. The priming method needs to be examined in a selection of relevant genotypes under a range of saline conditions.

Parasitoids are widely used as biological control agents to manage insect pest populations in greenhouses. To meet their energetic and nutritional requirements, adult parasitoids consume carbohydrate-rich sources such as (extra-)floral nectar and honeydew. However, these sugar sources are often scarce or even absent in greenhouses, compromising the effectiveness of parasitoids as biological control agents. To remedy this, artificial sugar solutions can be provided to sustain parasitoid populations. To develop an artificial sugar solution that supports parasitoids, proper selection of sugars is critical. In this study, we investigated the innate gustatory response and survival of the egg parasitoid Trissolcus basalis (Wollaston) on eight plant- and/or insect-derived sugars (fructose, glucose, maltose, mannose, melezitose, rhamnose, sucrose and trehalose). Our results show that T. basalis can consume a wide range of sugars and survive on them. Five sugars (sucrose, fructose, maltose, melezitose and trehalose) increased its longevity more than seven-fold compared to the water control. For two sugars, sucrose and trehalose, the parasitoid's realized fecundity was monitored after various time periods during which the parasitoids were fed with the sugars (1 day, 1 week, 2 weeks, and 3 weeks). The results indicate a prolonged period of parasitism compared to the water control because of a longer lifespan when fed on the sugars. Altogether, our findings provide valuable insights for the development of an artificial sugar solution that supports the performance of T. basalis, potentially enhancing the biological control of important pest species such as Nezara viridula (Linnaeus).

Timely and accurate macadamia identification is the key to automated orchard harvesting. This study proposes an improved recognition method for the YOLOv7 model to address fruit overlap, leaf-trunk occlusion and small target problems in complex backgrounds. First, the novel BiFormer attention mechanism is introduced. This mechanism utilizes two-layer routing to achieve dynamic sparse attention, effectively reducing the number of computations, enhancing the perception of small-scale targets. Second, the asymptotic feature pyramid network (AFPN) replaces the YOLOv7 backbone network, reducing the semantic differences and parameters between different layers and improving small target detection in complex scenes. In addition, the repulsion loss function replaces the YOLOv7 default loss function to address dense fruit arrangement and fruit occlusion in the data set. This successfully reduces false detections. The validity of the model is verified by ablation and comparison experiments, which show that the improved YOLOv7 model achieves an average accuracy, precision, recall and F₁ value of 99.7%, 99.6%, 99.3% and 99.4%, respectively. The average accuracy of the improved model increased by 7.5 percentage points compared with that of the YOLOv7 model. Overall, the improved YOLOv7 model can accurately recognize macadamia under complex lighting and background conditions with high detection accuracy and robustness.

Insecticide applications for controlling insect pests drive the rapid phenotypic evolution of resistance traits within populations. In two decades, the brown planthopper, Nilaparvata lugens, has rapidly developed resistance to imidacloprid, a neonicotinoid insecticide, but its resistance to dinotefuran has not developed as quickly. We assume that the genetic mechanism underlying the resistance evolution of N. lugens differs between the imidacloprid- and dinotefuran-resistant phenotypes. Dinotefuran-resistant strains, collected from a paddy field in Kumamoto in 2013 (Res-D13) and 2014 (Res-D14), were subjected to quantitative genetic analysis. The realized heritabilities of dinotefuran resistance were 0.091 (Res-D13) and 0.084 (Res-D14) after the 15th generation of selection. Reciprocal cross experiments between Res-D13 and the susceptible strain (Sus-strain), and between Res-D14 and the Sus-strain, showed that the degree of dominance for dinotefuran resistance ranged from 0.34 to 0.57. Analysis of the F₂ population and backcrosses to the parental strains indicated that dinotefuran resistance is a quantitative trait controlled by multiple genes on autosomal chromosomes. We propose that the realized heritability and the mode of inheritance of dinotefuran resistance well explain the slow development of dinotefuran resistance in field N. lugens populations.

In this study, we evaluated the biocontrol effect against Meloidogyne incognita of Streptomyces (strain JXGZ01) obtained from yam field soil. Results showed that the mortality of second-stage juveniles (J2s) treated with an undiluted culture filtrate of JXGZ01 for 12 and 24 h was 70.86% and 85.58%, respectively. The twofold dilution resulted in 66.41% and 81.55% mortality for 12 and 24 h, respectively. Both strong acids and alkali significantly reduced the nematicidal activity of the culture filtrate, but neither temperature nor ultraviolet irradiation had any significant effect. In addition, two, four and eightfold dilutions inhibited the hatching of M. incognita eggs by 91.3%, 83.7% and 75.7%, respectively. Finally, the results of a pot experiment showed that the nematodes treated with different dilutions of culture filtrate significantly reduced the number of galls by 65.87%–97.30%. Compared with those of the control group, the treatments reduced the number of egg masses and J2s by 38.17%–92.84% and 37.57%–93.82%, respectively, and the eggs hatching rate was reduced by 27.92%–45.27%, relative to the control group. Data indicate that strain JXGZ01 has a potential and application value for development as a biocontrol agent for M. incognita.

For many phytophagous insects, oviposition plays a key role in the selection of an appropriate host. A more comprehensive understanding of the factors influencing this behaviour in pest insects provides a basis for the development of new management strategies. Herein, the determinants of oviposition were assessed in the cabbage stem flea beetle, Psylliodes chrysocephala (Coleoptera: Chrysomelidae), an insect specialized on the Brassicaceae family and a major pest of oilseed rape crops in Europe. To this end, a controlled condition experiment was conducted, in which a range of host plants exhibiting varying degrees of acceptability for feeding were presented to mature females. A superior host, Brassica rapa pekinensis, an intermediate one, Brassica napus, and a non-host plant, Iberis amara, were used. An additional treatment involved wrapping the plants in micro-perforated plastic bags to prevent feeding on aerial parts. The results demonstrated that contact with the host plant, and more particularly feeding, stimulated oviposition, with this effect being more pronounced in B. napus. Indeed, for the same amount of feeding, females laid significantly more eggs when feeding on B. napus than when feeding on B. rapa pekinensis. Additionally, a sequential experiment demonstrated that the intensity of oviposition is subject to rapid adaptive changes, as it is exclusively dependent on the current dietary conditions, with no influence of past dietary regimens. The quantification of macronutrients indicated the potential influence of plant-digestible carbohydrates on these outcomes. Further investigation is required to determine the impact of the plant nutritional quality and defences on oviposition.

In this study, we assessed the genetic relatedness of 11 representative Pseudomonas syringae pv. syringae (Pss) strains isolated in Serbia from different herbaceous and woody plant species, as well as one reference Pss strain, using various molecular tools such as repetitive element palindromic PCR, arbitrarily primed PCR, insertion sequences 50 PCR (IS50-PCR) and multilocus sequence analysis (MLSA). Their virulence traits were also assessed by inoculating detached pear and lilac leaves, as well as immature cherry fruitlets. The results indicated genetic heterogeneity among the strains, which formed a complex network with prominent clustering patterns. While four distinct groups could be recognised when comparative Pss strains from the database were included in the analyses, the strains in focus of this study segregated into two distinct genetic groups labelled PssG-2 and PssG-3. MLSA findings mostly matched the IS50-PCR results, while virulence assays helped distinguish sweet cherry (RE05, RE3) and pumpkin (PS-T71) strains as the most virulent. Only strain Pss25, originating from pear, exhibited host specificity.

Fusarium crown and root rot (FCRR) of asparagus caused by Fusarium spp., results in plant stunting, wilting, vascular discoloration, and root rot reducing the longevity and productivity of this perennial vegetable. Metam-sodium is a broad-spectrum pre-plant fumigant commonly used in Michigan asparagus nurseries to mitigate FCRR by reducing disease presence in 1-year-old crowns that are used for establishing production fields. The objective of the current study was to compare the diversity of Fusarium species associated with nursery-grown asparagus crowns from soils fumigated preplant with metam-sodium to those from unfumigated nurseries. Based on sequences of the TEF-1α (transcription elongation factor 1-alpha) region, seven Fusarium spp. were identified including F. oxysporum, F. proliferatum, F. solani, F. acuminatum, F. avenaceum, F. graminearum and F. incarnatum-equiseti. Fusarium oxysporum was the most frequently isolated species (92%). No significant differences were noted between Fusarium populations isolated from nurseries that had been fumigated with metam-sodium and those isolated from the nursery that had not been fumigated. Pathogenic isolates of F. oxysporum were recovered from nurseries at a similar rate regardless of fumigation status. These findings indicate that metam-sodium is inadequate as a pre-plant treatment for Fusarium crown and root rot and alternative strategies need to be explored.