【Objective】Analyzing the yield and yield related traits of Sichuan wheat varieties from 2000 to 2020, providing reference for genetic improvement of yield in Sichuan wheat varieties. 【Method】From 2019 to 2022, a community trial design was used to measure the yield and related traits of 145 wheat varieties in Sichuan Province since 2001 to 2016, as well as 60 high-yield wheat varieties (Varieties with top yields in regional trials in Sichuan Province over the years) since 2000 to 2020. This data was used to analyze the trend of yield and yield related trait changes in Sichuan wheat cultivars cultivated from 2000 to 2020. 【Result】145 Sichuan wheat varieties from 2001 to 2016 have an average annual genetic gain of 37.20 kg·hm-2 or 0.66% in yield. Grain number per spike and effective spike number per unit area showed an increasing trend, while thousand grain weight and plant height showed a decreasing trend. Correlation analysis showed that effective spike number per unit area was positively correlated with yield. Path analysis showed that the continuous increase of effective spike number per unit area (annual increase 0.42×104/hm2 or 0.13%) was the main factor for the increase of yield potential of high-yielding varieties. The average annual yield genetic gain of 60 high-yield wheat varieties from 2000 to 2020 was 61.10 kg·hm-2 or 0.89%, the effective spike number per unit area showed an increasing trend, the plant height showed a decreasing trend, and the grain number per spike and thousand grain weight had almost no change. Correlation analysis shows that there was a significant positive correlation between yield and the number of effective ears per unit area. Path analysis showed that the continuous increase in effective spike number per unit area (with an average annual increase of 1.80×104/hm2 or 0.51%) was also a major factor in improving the yield potential of 60 high-yield wheat varieties in Sichuan from 2000 to 2020. 【Conclusion】The improvement and breeding of wheat yield heritage in Sichuan Province has made some progress, especially the improvement effect of high yield breeding is remarkable, and the yield level of wheat varieties in Sichuan Province is gradually increasing. The continuous increase in effective ears per unit area was the main factor for improving the yield potential of Sichuan wheat varieties. High grain number per spike and thousand grain weight are important foundations for high yield in Sichuan wheat, but their genetic improvement is in a bottleneck period. Increasing the effective spike number per unit area is the key to furtherly improve the yield of wheat in Sichuan.
【Objective】To understand the effects of high temperature stress on the agronomic traits, yield, its components and grain quality of sesame, to accurately evaluate the high temperature tolerance level of different sesame varieties at full flowering stage, and to screen the high temperature tolerant sesame varieties.【Method】24 sesame varieties were treated with normal temperature (CK) and high temperature stress(H) at full flowering stage for 7 days. The agronomic traits such as plant height, initial capsule site, number of capsules per plant, number of capsules per capsule, 1000-grain weight, yield per plant and quality indexes such as water content, oil content and protein content were measured at maturity stage. The heat tolerance of different sesame varieties at full flowering stage was comprehensively analyzed and evaluated by means of principal component and cluster analysis.【Result】Different varieties, temperature treatments and interactions had significant effects on the indexes of sesame. After high temperature stress, compared with CK, the yield per plant, 1000-grain weight, number of capsules per plant, number of capsules per capsule, initial capsule site, capsule length and plant height of sesame decreased by 33.47%, 13.62%, 7.76%, 5.75%, 2.61%, 1.64% and 1.40%, respectively. Among which 1000-grain weight and yield per plant decreased the most, and the differences reached significant level. The difference of end length and protein content was no significant, which was 13.43% and 1.55% lower than that of the CK. The water content and oil content increased by 0.90% and 0.17% respectively compared with CK, and the difference was not significant. There is a certain correlation between the high temperature tolerance coefficients of different varieties and various indexes. The high temperature resistance coefficient was analyzed by principal component analysis, and five independent comprehensive indexes were established, and the contribution rates were 30.74%, 25.82%, 13.18%, 10.12% and 8.33%, respectively, reflecting 88.19% of the original information. The weight of each index was calculated by component matrix and eigenvalue, and the physiological comprehensive index model of high temperature stress (HTSPCI) was constructed. According to the cluster heat map analysis of high temperature tolerance coefficient of each individual index, 24 sesame germplasm resources were divided into 4 grades: high temperature resistant type, medium high temperature tolerance type, medium heat sensitive type and heat sensitive type, respectively. And the yield loss rate per plant (X6) of 6 high temperature resistant varieties was ≤9.50%, 6 medium high temperature resistant varieties was 9.50%<X6≤30%, 10 medium heat sensitive varieties was 30%<X6≤70% and 2 heat sensitive varieties was X6>70%.【Conclusion】High temperature treatment significantly affected the growth and development of sesame at full flowering stage. A comprehensive index model of high temperature stress was established by combining agronomic traits and quality indexes with principal components-cluster analysis, and 6 varieties with high temperature tolerance were selected, which could be used to evaluate the high temperature tolerance of different sesame varieties.
【Objective】 Oat plant height affects the productivity per plant and the yield per unit area together with planting density. This study explores automatic, real-time, and precise methods for acquiring oat plant height in a field environment, aiming to provide technical references for the automated field management of oat. 【Method】 Firstly, an oat depth image acquisition system was built based on Intel RealSense D435 depth camera and LabVIEW software development platform. Taking Oat ‘Pinyan No. 4’ as the research object, 26 376 modeling data and 2 205 test data were obtained during the whole oat growth process. The average and highest plant height of oats in each depth image were measured with a scale. The quantity of modeling data and test data in each height range of oat plant was relatively balanced. The images were preprocessed by high restoration, grayscale and scaling. Each image was tagged with two labels, one for the average and one for the highest plant height of the oats in the image. Then, based on 8 classical convolutional neural network models, the last layer (classification layer) of each network model was removed, and two fully connected layers with single nodes and no activation function were added to construct the double output regression convolutional neural network estimation model. Mean square error (MSE) was used to evaluate the accuracy of each model in estimating oat plant height. Finally, based on the TensorFlow deep learning platform, Modified EfficientNet V2L was selected as the estimation model by 5-fold cross-validation using the modeling data. 【Result】 The generalization performance of Modified EfficientNet V2L model to estimate oat plant height was investigated using test data not involved in model training. The mean absolute error (MAE), root mean square error (RMSE) and mean relative error (MRE) to estimate oat average plant height were 2.30 cm, 2.90 cm and 4.4%, respectively. Meanwhile, the MAE, RMSE and MRE to estimate highest plant height was 2.24 cm, 2.82 cm and 4.1%, respectively. The average estimated time of the model was 52.14 ms. The accuracy of estimating crop plant height using this method was similar to that of existing methods. However, when estimating crop plant height used this method, once the estimation model was trained, the average and maximum crop plant height could be automatically estimated by inputting the pre-processed crop depth image, and the average estimation time could meet the real-time requirements of crop plant height acquisition. The relative errors in estimating average plant height and maximum plant height of oat showed a general decline trend with the increase of crop plant height. This might be because when crop plant height was low, the estimated results were more affected by soil fluctuation. The results of feature map visualization showed that the model could estimate plant height according to the height and contour of oat in depth image. Finally, an oat plant height estimation system was built based on 2023 Q1 version of LabVIEW software development platform. After depth camera acquiring oat depth images, the system could accurately estimate average and highest oat plant heights in real time without manual intervention, and the average estimation time was less than 0.1 seconds. The system could be used for crops irrigation and fertilization management. It could also be installed on the tractors to control the height of a sprinkler head during spraying, and to adjust the height of a cutting table during harvesting. 【Conclusion】 The depth image and double output regression convolutional neural network could be used to estimate oat plant height, and the accuracy could meet the production demand, so this method provided a basis for field management of oat crops.
【Objective】The objective of this study is to explore the vibration propagation laws of mating calls of the brown planthopper (BPH), Nilaparvata lugens, and to provide the theoretical basis and practical guidance for the development and optimization of novel techniques for physical pest control.【Method】Simulating a paddy field scenario, using the root mean square (RMS) as the measurement index of vibration intensity, the PDV-100 digital laser vibrometer was applied to test and analyze the propagation and attenuation characteristics of vibrations generated by different types of loudspeakers (as vibration sources) in water, air, and on rice plants. Based on the principle of substrate-borne vibration in insects, a steel needle point-touch method was used to play back female mating calls at varying intensities, which aimed to test the response rate of males during their mating active period and determine the range of vibration intensity they could perceive.【Result】When the vibration source was placed in water or air, the vibration intensities of the sinusoidal waves on rice plants decreased with increasing distance within the range of 10 to 500 cm. However, except for the position 10 cm from the vibration source, there was no significant difference in vibration intensity between the two modes at other positions (60-500 cm). At 60 cm, the intensity decreased by 84.87% in water and 73.08% in air compared to that at 10 cm. Furthermore, the application of higher-power directional loudspeakers revealed significantly extended propagation distances of sinusoidal wave signals in the air. Vibration sources with 20 and 30 W output power were attenuated by 87.27% at 15 m and 66.72% at 20 m, respectively. The vibration intensity on rice plants when playing back pre-recorded female and male courtship vibration signals showed no significant difference and increased with the signal strength of the vibration source, following an exponential function relationship. Additionally, the response rate of N. lugens males to female signals of different intensities showed significant differences. When the vibration velocity ranged from 782.2 to 835.9 μm·s-1, over 83% of male insects exhibited a calling response; however, when the vibration velocity was between 335.2 and 425.4 μm·s-1 or lower, fewer than 47% of males responded.【Conclusion】The disruptive vibrational signals can propagate to rice plants through the airborne pathway, with greater vibration source intensity resulting in farther propagation distances. The vibration conduction characteristics of rice plants are similar at different growth stages, but rice stems conduct vibrations more effectively than leaves. The results of response tests of N. lugens adults to different vibration intensities can serve as a basis for evaluating the effectiveness of disruptive vibrational signals in controlling N. lugens in the future.
【Objective】It has been reported that Nilaparvata lugens (brown planthopper, BPH) exhibits a preference of endangering rice plants infested by Chilo suppressalis (striped stem borer, SSB). However, it remains unclear whether this phenomenon is influenced by the developmental stage of N. lugens and the rice variety. This study aims to investigate the effects of rice varieties and developmental stages of N. lugens on the preference for C. suppressalis-infested rice plants, as well as how volatiles mediate this behavior, so as to provide a scientific basis for formulating green pest control strategies.【Method】Through indoor choice experiments, the attraction of different developmental stages of N. lugens (including 3rd-4th instar nymphs, newly emerged females, gravid females) to nine rice varieties, including Zhongzheyou 8, both damaged and undamaged by C. suppressalis, was observed. Based on these observations, representative varieties showing significant differences in attraction were selected for further analysis. RT-qPCR was used to detect changes in the expression of volatile synthesis-related genes in three rice varieties (Zhongzheyou 8, 9311, and Minghui 63) following pest infested.【Result】Among the nine rice varieties, different developmental stages of N. lugens consistently showed a preference for rice plants infested by C. suppressalis, although this preference varied among rice varieties. For instance, newly emerged female N. lugens exhibited a significantly higher preference for Minghui 63 compared to Yongyou 538. Gene expression analysis revealed a significant increase in the expression levels of volatile synthesis-related genes OsCAS, OsLIS, OsHPL3, and OsRCI-1 in response to C. suppressalis infestation. However, when different developmental stages of N. lugens were co-infested with C. suppressalis, the expression levels of these genes could either increase or decrease compared to plants infested only by C. suppressalis, with specific effects depending on the developmental stage of N. lugens.【Conclusion】The preference of N. lugens for rice plants infested by C. suppressalis was commonly observed across the nine tested rice varieties. However, significant differences in the degree of preference were noted among different developmental stages of N. lugens across these varieties. Notably, variations in preference among developmental stages of N. lugens were primarily observed in the selection of rice varieties Yongyou 538, Zhongzheyou 8, and Minghui 63 by newly emerged female. Infestation only by C. suppressalis or in conjunction with N. lugens resulted in increased expression levels of the genes OsCAS, OsLIS, OsHPL3, and OsRCI-1, indicating that pest infestation in rice plants can regulate the synthesis of rice volatiles, thereby influencing the host selection behavior of N. lugens.
【Objective】The Toll receptor is one of the key effector factors in the Toll signaling pathway of the innate immune system in insects. This article aims to identify the Toll receptor genes of three types of rice planthoppers (Nilaparvata lugens, Sogatella furcifera, and Laodelphax striatellus), explore the potential functions of the Toll receptor in these three species, and investigate the interspecies differences, so as to provide a theoretical basis for the study of the immune development of rice planthoppers and for the control and prevention of these pests.【Method】Bioinformatics methods were used to identify Toll receptor genes from the genomes of three species of rice planthoppers, and the gene structure and characteristics, physicochemical properties and structural domains of the encoded proteins, chromosome localization and phylogenetic evolutionary relationships were analyzed. Artificial intelligence software AlphaFold 3 was used to predict the three-dimensional structure of Toll receptors and compare it with the known structures and functions of Toll receptors from other species to predict their potential functions and interspecific functional differentiation. Transcriptome data were used to quantitatively analyze the expressions of Toll receptor genes in different tissues and at different developmental stages.【Result】A total of 6, 7, and 6 Toll receptor genes were identified in the genomes of N. lugens, S. furcifera, and L. striatellus, respectively, all of which are distributed on chromosomes 1, 4, and 7, with a clear distribution pattern. The Toll gene family in the three species of rice planthoppers is distributed with one gene on chromosomes 1 and 4, and the rest on chromosome 7. The coding sequence lengths of the Toll receptor genes in the three species of rice planthoppers range from 2 676 to 4 158 bp, with the number of exons ranging from 1 to 7, and the encoded protein sequence lengths range from 891 to 1 385 aa, with molecular weights ranging from 103.31 to 158.25 kDa and theoretical isoelectric points ranging from 5.42 to 6.54. Phylogenetic development analysis showed that the Toll receptor gene family of the three species of rice planthoppers can be divided into six subfamilies, which are homologous to the Toll, Toll6, Toll7, Tollo (Toll8), and Toll9 of other insects. The comparison analysis of the extracellular structures predicted by AlphaFold 3 with those of Toll receptors from other species showed that two Toll receptors in the Toll receptor gene family of S. furcifera were potentially related to virus interactions, one in the Toll receptor gene family of L. striatellus, and none in the Toll receptor gene family of N. lugens. Transcriptome quantitative results showed that the Toll receptor genes in the three species of rice planthoppers were expressed in different tissues and at different developmental stages, suggesting that they may have different functions and participate in different divisions of labor.【Conclusion】A total of 19 Toll receptor genes were identified in three species of rice planthoppers, and their related structures and functions were analyzed and predicted. The study revealed potential differences in the roles played by Toll receptors in the development and immune response, particularly in virus immunity, within the insect body among these three species of rice planthoppers.
【Background】Sphingolipids are the second major type of membrane lipids and mediate various biological processes as signal transducers, including cell growth, development, reproduction and apoptosis. Sphingolipid metabolism is tightly regulated by sphingolipid metabolizing enzymes to maintain the homeostasis of metabolism in vivo.aaaaa【Objective】The objectives of this study are to investigate the relative transcript levels of genes related to the sphingolipid metabolism pathway after silencing of the core components of microRNA (miRNA) biosynthesis pathway, NlAgo1, NlDicer1 and NlDrosha by RNA interference (RNAi), and analyze the differentially expressed miRNAs after silencing of serine palmitoyltransferase 1 (SPT1) and sphingomyelinase 4 (SMase4) gene combined with small RNA sequencing of Nilaparvata lugens, explore the role of miRNAs in the sphingolipid metabolism of N. lugens, and to provide a new molecular target for pest control.【Method】RNAi was performed with double stranded RNAs (dsRNAs) targeting NlAgo1, NlDicer1 and NlDrosha at 1 day post adult eclosion (1 PAE), respectively, and dsGFP was used as control. The ovaries at 5 PAE were dissected and β-actin was used as internal reference gene, the transcript levels of genes related to the sphingolipid metabolism pathway were detected by reverse-transcription quantitative PCR (qRT-PCR). miRNAs that may regulate the expression of NlSPT1 and NlSMase4 were predicated based on small RNA libraries combined with miRNA-target prediction software. Differentially expressed miRNAs after the silencing of NlSPT1 and NlSMase4 were identified and the target gene enrichment was analyzed by small RNA sequencing.【Result】RNAi-mediated silencing of NlAgo1, NlDicer1 or NlDrosha significantly up-regulated the expression of genes related to the sphingolipid metabolism pathway, including NlSPT1 and NlSMase4 in ovaries. Target gene prediction revealed 6 miRNAs and 13 miRNAs that could bind NlSPT1 and NlSMase4. The target genes of differentially expressed miRNAs that silencing NlSPT1 and NlSMase4 were significantly enriched in biological processes, including nuclear and protein binding, as well as metabolic pathways such as endocytosis, endoplasmic reticulum processing, MAPK signaling pathway, TOR signaling pathway, apoptosis, and lipid metabolism.【Conclusion】NlAgo1, NlDicer1, and NlDrosha-dependent miRNAs affect sphingolipid metabolism by influencing the expression of genes encoding sphingolipid metabolizing enzymes. The silencing of NlSPT1 and NlSMase4 induced changes in miRNA expression levels in N. lugens ovaries. These research results can provide a theoretical basis for pest control based on sphingolipid metabolism genes.
