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991.
针对当前生猪规模化养殖过程中基于热红外技术的生猪体温测量效率低的问题,提出了一种基于改进YOLO v7的生猪群体体温检测方法。改进YOLO v7算法在Head层引入VoV-GSCSP结构,降低网络结构复杂度;使用内容感知特征重组(Content-aware reassembly of features,CARAFE)替换模型原始上采样算子,提高特征图放大后的品质,强化生猪头部区域有效特征;引入感受野增强模块(Receptive field enhancement module,RFE),增强特征金字塔对生猪头部特征的提取能力。本文改进YOLO v7算法对于生猪头部的检测精确率为87.9%,召回率为92.5%,平均精度均值(Mean average precision,mAP)为94.7%。与原始YOLO v7相比,精确率提高3.6个百分点,召回率提高7.0个百分点,mAP提高3.6个百分点。该方法首先自动检测生猪头部区域,再利用头部最大温度与耳根温度的高相关性,最终自动获取生猪体温。温度提取平均绝对误差仅为0.16℃,检测速度为222f/s,实现了生猪群体体温的实时精准检测。综合上述试验结果表明,该方法能够自动定位生猪群体的头部区域,满足生猪群体体温测定的高效和高精度要求,为群养生猪体温自动检测提供了有效的技术支撑。  相似文献   
992.
993.
994.
As a typical tropical crop, cassava (Manihot esculenta Crantz) has the characteristics of drought resistance, barren resistance, high biomass and so on. In addition to being used for food and forage, it can also be used for production, processing and starch extraction. Due to highly heterozygous cassava genome, breeding is more difficult. Enriching the genetic diversity of cassava germplasm, comprehensively evaluating its genetic background and traits, and discovering superior alleles that control excellent traits are of great significance for cassava breeding in the future. In order to analyze the genetic diversity, genetic relationship and population structure of cassava germplasm in Brazil, 7946 SNPs and 1997 InDels molecular markers were used. Population structure analysis was performed by ADMIXTURE software, and principal component analysis was performed by GCTA software. Brazilian cassava was divided into nine subgroups, and was roughly consistent with the results of cluster analysis using PHYLIP. Among them, subgroup 1, subgroup 2, subgroup 4, subgroup 6, and subgroup 8 could be clustered together respectively, while the samples of other subgroups could be roughly clustered, and there was a certain cross between the samples. The genetic diversity of cassava germplasm in Brazil (0.274) was higher than the genetic diversity level of cassava germplasm in China and Nigeria. Subgroup 5 of Brazil cassava had a relatively high genetic diversity (0.29). The genetic differentiation of subgroups was low (the genetic differentiation vary from 0.03 to 0.15), but higher than domestic cassava germplasm. The genetic distance between cassava accessions varied from 0.084 to 0.297, with the average of 0.228. The results of this study can provide a basis for subsequent association analysis to identify great alleles and introduction.  相似文献   
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996.
ABSTRACT

Sunflower is a species that is sensitive to local climate conditions. However, studies that use artificial neural networks (ANNs) to evaluate this influence and create tools such as agricultural zoning of climate risk (ZARC) have not been conducted for this species. Due to the importance of sunflower as a human food source and for biodiesel production, and also the necessity of conducting research to evaluate the suitability of this oleaginous species under different climatic conditions. Thus, we seek to construct a ZARC for sunflower in Brazil simulating sowing on different dates and using meteorological elements spatialized by ANNs. Climate data were used: air temperature (T), rainfall (P), relative air humidity (UR), solar radiation (MJ_m?2_d?1) and wind velocity (U2). Climatic regions considered suitable for the cultivation of sunflower had average annual values for T between 20 and 28°C, P between 500 and 1.500 mm per cycle, and soil water deficit (DEF) below 140 mm per cycle. A neural network is an efficient tool that can be used in spatialization of climate variables quickly and accurately. Sunflower sowing in the spring and summer are the ones that provide the largest suitable areas in southeastern Brazil, with 58.13 and 64.36% of suitable areas, respectively.  相似文献   
997.
Summary The appearance, a few years ago, of red core disease (Phytophthora fragariae Hickman) in strawberry crops in the Netherlands, has made it desirable to grow resistant varieties and to include red core resistance in our breeding programme.An account is given of the results of some field trials in 1968–1970 on a very wet, sandy soil, infected with P. fragariae, involving varieties, selections and seedling progenies.In both years distinct differences in resistance and susceptibility occurred between varieties and selections. The seedling progenies gave significant differences in percentages of surviving, healthy plants.Samenvatting Het optreden van rood wortelrot (Phytophthora fragariae Hickman) enkele jaren geleden in de aardbeiteelt in Nederland, heeft het gewenst gemaakt resistente rassen te telen en resistentie in ons veredelingsprogramma op te nemen.In dit artikel worden de resultaten vermeld van enkele veldproeven met rassen, selecties en zaailingpopulaties in de jaren 1968–69 en 1969–70 op een zeer natte, met P. fragariae besmette zandgrond.In beide jaren traden duidelijke verschillen in vatbaarheid op tussen de rassen en selecties. De zaailingpopulaties vertoonden eveneens duidelijke verschillen in de percentages overlevende, gezonde planten.  相似文献   
998.
Summary The main constraint of using Ogura male-sterile cytoplasm in Brassica is the induction of leaf yellowing at low temperature and the low seed set. But whether or not the cytoplasm can disturb the general commerical performance of the plants is not well-known. Therefore, this work was carried out with the purpose of evaluating Ogura cytoplasmic male-sterile cabbage hybrids and compare them to genomic similar male-fertile ones and to the most popular cabbage hybrid cultivated in Brazil. Harvest data showed an effect of the cytoplasm on reducing plant and head weight, core length and head length and width, although not altering heading index, shape and core indexes, nor head compactness. On the other hand, it was observed also that a careful selection of the parental lineages can produce male-sterile hybrids as good as their male-fertile analogues. All the evaluated hybrids were similar or better than the check for the characteristics under study.Abbreviations dat - days after transplanting - CNPH - National Center for Vegetable Crops Research  相似文献   
999.
Protoplast fusion can be used to produce somatic hybrids of species that cannot be obtained by sexual hybridization. The possibility to introgress genes from Solanum species into the cultivated tomato species Lycopersicon esculentum, and to obtain novel cytoplasm-nucleus combinations (cybrids) was considered as an important strategy to extend the genetic variation available for tomato breeding. Somatic hybrids between L. esculentum and other Lycopersicon species, as well as between L. esculentum and Solanum or Nicotiana species, have been produced. Specific mutants, genotypes with antibiotic resistances, and metabolic inhibition by iodoacetate or iodoacetamide and irradiation were used for the selection of hybrids. In addition, the improvement of protoplast culture techniques and the use of the favourable tissue culture traits derived from species such as L. peruvianum, which have been introduced into tomato by classical breeding, allowed the efficient recovery of somatic hybrids. However, the occurrence of somatic incongruity in fusion combinations of L. esculentum and Solanum and even more in L. esculentum and Nicotiana, did not allow the production of true cybrids and/or fertile hybrids, indicating the importance of both cytoplasm-nucleus and nucleus-nucleus interactions in somatic incongruity. Another problem with fusions between distantly related species is the strongly reduced fertility of the hybrids and the very limited homoeologous recombination between chromosomes of the parental species. Partial genome transfer from donor to recipient through microprotoplast (+) protoplast fusion, and the production of monosomic or disomic chromosome addition lines, light overcome some of these problems. In symmetric somatic hybrids between L. esculentum and S. tuberosum the occurrence of limited somatic and meiotic recombination was demonstrated. Fertile progeny plants could be obtained, though at a low frequency, when embryo rescue was performed on a large scale after backcrossing hexaploid somatic tomato (+) potato hybrids with a tetraploid potato genotype. The potential value of genomic in situ hybridization (GISH) and RFLPs for the analysis of the genome/chromosome composition of the hybrids has been demonstrated for intergeneric somatic hybrids between Lycopersicon and Solanum.Abbreviations cpDNA chloroplast DNA - mtDNA mitochondrial DNA  相似文献   
1000.
Relationships among American and Spanish populations of maize   总被引:1,自引:0,他引:1  
Summary Two experiments were carried out with two objectives. First, to establish the phenetic relationships among the maize (Zea mays L.) landraces from Galicia (Northwestern Spain) maintained at the Misión Biológica de Galicia. Second, to assess the resemblance between a collection of Spanish populations (including the landraces from Galicia) and a set of US Corn Belt varieties. For the first objective 73 varieties from Galicia, along with 9 hybrid checks, were grown in 9×9 simple lattices at two locations for two years. For the second objective 131 populations from the US Corn Belt and Spain, along with 9 hybrid checks, were grown for three years in unreplicated experiments. Cluster analyses were carried out with the first principal components that accounted for a significant amount of the total variation. Four groups were found among the landraces from Galicia. The populations from Spain and America were classified as belonging to nine main groups. The replicated experiment was more accurate than the unreplicated one. However, it is concluded that an unreplicated test grown in several environments is accurate enough to detect the main groups, although some inaccuracies should be expected.  相似文献   
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