良种良法是获取高产的保证   总被引：1，自引：0，他引：1  

班秀文 《广西蔗糖》2001,(3):5-6,31

1　前言　　我省蔗区主要分布于南、北盘江 ,红水河流域的低热河谷地区 ,95%以上的甘蔗分布在旱坡地 ,缺乏灌溉条件 ,不能做到旱期引灌 ,雨季排水 ,人为抗拒自然灾害的能力弱 ;雨水对蔗地冲刷 ,水土流失严重 ,土壤保水保肥力差 ,既破坏了生态平衡又影响了甘蔗生长。因此老式栽培方式 ,是造成我省甘蔗产量低的重要因素之一。2　贵州蔗区的现状　　我省蔗区以春植蔗为主 ,播种期一般在3月中旬～ 4月上旬 ,此时蔗区月平均温度在1 2 .5～ 2 2 .9℃之间 ,月降雨量为 31 .7～88.1 mm。甘蔗种芽的萌发温度基本满足 ,然而蔗种的萌发却受到土壤含水量…  相似文献   

影响精液冷冻和人工授精效果的因素     

吴结革  茆达干 《动物医学进展》2003,24(5):48-50

通过对精液冷冻保存的细胞反应原理的阐述 ,指出冷冻保护剂甘油对精液保存具有利弊效应 ,提出精子膜脂组成的差异使得不同品种的精子对冷冻损伤的易感性不同。雌性生殖道解剖结构的品种差异 ,精子形态 ,精子运行机制的细微差异 ,人工授精时间及精子的运行能力 ,采精方式等因素对精液冷冻保存和人工授精的成功有决定性作用。研究精子质膜的生物学特性可解决低活力精子的问题 ,然而这并不能解决冷冻后精子质量的个体差异。对精细胞基因组的研究可以找出这些个体的遗传差异。因此 ,冷冻精子和精原细胞 (用于细胞外注射 )的差异已经成为完整基因组问题。  相似文献   

Pregnancy Rates in Repeat-breeder Heifers Following Multiple Artificial Inseminations during Spontaneous Oestrus     

Bhupender Singh  Fernando Saravia  Renée B?ge  Heriberto Rodríguez-Martínez 《Acta veterinaria Scandinavica》2005,46(1):1-12

Hormonal asynchronies during oestrus, related to the presence of suprabasal plasma-progesterone (P4) concentrations and a delayed ovulation, interfere with the fertility of repeat-breeder heifers (RBH). Since tubal dysfunction can occur in connection with hormonal asynchronies and constrained availability of fertile spermatozoa at the time of ovulation, the present study tested the hypothesis that frequent sperm deposition from onset of oestrus to ovulation may improve pregnancy rates in RBH. Five RBH and five virgin heifers (VH; controls) were repeatedly artificially inseminated (AI) at 6 h intervals from onset of oestrus to spontaneous ovulation. Hormone analyses revealed suprabasal P₄ concentrations and a delay in the occurrence of the luteinising hormone (LH) surge, but a normal cortisol profile in RBH. Compared with controls, RBH presented longer interval from onset of oestrus to ovulation, and therefore, received more AIs. Pregnancy rates in RBH reached control levels (60%; NS), indicating that the hypothesis might be correct. Pregnancy rates in VH were below the expected range, presumably attributed to a deleterious influence of the frequent handling. The study suggests that pregnancy rates can be improved in RBH by frequent AI in relation to spontaneous ovulation. However, this practice of repeated manipulations, while seeming not to show adverse effects, lacks practicality for routine use.  相似文献   

Segment-based coancestry,additive relationship and genetic variance within and between the Norwegian and the Swedish Fjord horse populations     

Hanne Fjerdingby Olsen  Saija Tenhunen  Nils Ivar Dolvik  Dag Inge Våge  Gunnar Klemetsdal 《Acta Agriculturae Scandinavica, Section A - Animal Sciences》2020,69(1-2):118-126

ABSTRACT

The Fjord horse originates from Norway but forms a global population due to several small populations in foreign countries. There exists no information about the additive relationship and the genetic variance between these subpopulations. By collecting blood samples from Norwegian and Swedish Fjord horses, a sample of 311 Norwegian and 102 Swedish horses gave 485,918 SNPs available for analysis. Their inbreeding coefficients were calculated and compared to the pairwise coancestry and the shared genomic segments. The effective population size was almost similar with the two methods in the Norwegian Fjord horse population (63 and 71), but very different in the Swedish population (269 and 1136) and unprecise due to a much smaller number of observations. The study showed that coancestry from shared genomic segments can be used to estimate additive genetic relationship and genetic variation within and between the global populations of the Fjord horse.  相似文献   

凯特芒果不同叶果比对果实品质和营养元素含量的影响   总被引：1，自引：0，他引：1  

杜邦  李贵利  周文静  刘斌  黄云 《广东农业科学》2011,38(24)

通过调整叶果比例,研究凯特芒果不同叶果比处理对果实品质和营养元素含量的影响.结果表明:不同叶果比处理对果实品质影响较小,其中糖酸比处理间差异显著,叶果比为30/1的处理与其他处理相比,总酸含量最小、为0.27％,糖酸比和固酸比均达最大值、分别为54.837和68.859;不同叶果比处理对果实中的营养元素N、P、Ca、Mn、B含量有不同程度的影响.总体来说,从不同叶果比对果实品质和营养元素含量的影响来看,凯特芒果的叶果比为30/1时较理想.  相似文献   

The Influence of Organic and Integrated Production on Nutritional,Sensory and Agricultural Aspects of Vegetable Raw Materials for Food Production     

Stina Fjelkner-Modig  Håkan Bengtsson  Stig Nystrõm  Rolf Stegmark 《Acta Agriculturae Scandinavica, Section B - Plant Soil Science》2013,63(3):102-113

In a six-year crop rotation trial organically and integrated grown vegetables were produced according to current good agricultural practices, taking quality and quantity aspects into consideration. The raw materials assessed focussed on materials used for industrial food production. Nutritional, sensory and agricultural aspects were evaluated. Carrot, cabbage, onion, pea and potato are possible to grow organically for industrial purposes. Depending on crop, the yield was lower (65-90%) for organically grown compared to integrated grown. Cultivation of organic spinach and dill turned out to be difficult due to problems with weed and discoloration. The chemical analyses included pesticide residues, nitrate, glycoalkaloid, dry matter, vitamin C and 25 different minerals and trace elements. Overall, the organically grown crops had higher dry matter content than the integrated grown. However, when examining the data for the different crops contradictory results were noted. No significant differences due to growing system were noticed for vitamin C and the other nutrients except for 4 of the trace elements. The growing system did not influence the sensory properties.  相似文献   

Chitosan nanoparticles enhance developmental competence of in vitro-matured porcine oocytes     

Pantu Kumar Roy  Ahmad Yar Qamar  Xun Fang  Ghangyong Kim  Seonggyu Bang  Mahanama De Zoysa  Sang Tae Shin  Jongki Cho 《Reproduction in domestic animals》2021,56(2):342-350

Oxidative stress is inevitable as it is derived from the handling, culturing, inherent metabolic activities and medium supplementation of embryos. This study was performed to investigate the protective effect of chitosan nanoparticles (CNPs) on oxidative damage in porcine oocytes. For this purpose, cumulus–oocyte complexes (COCs) derived from porcine slaughterhouse ovaries were exposed to different concentrations of CNPs (0, 10, 25 and 50 µg/ml) during in vitro maturation (IVM). Oocytes treated with 25 µg/ml CNPs showed significantly higher levels of GSH, along with a significant reduction in ROS levels compared to control, CNPs10 and CNPs50 groups. In parthenogenetic embryo production, the maturation rate was significantly higher in the CNPs25 group than that in the control and all other treated groups. In addition, when compared to the CNPs50 and control groups, CNPs25-treated oocytes showed significantly higher cleavage and blastocyst development rates. The highest concentration of CNPs reduced the total cell number and ratio of ICM: TE cells in parthenogenetic embryos, suggesting that there is a threshold where benefits are lost if exceeded. In cloned embryos, the CNPs25 group, as compared to all other treated groups, showed significantly higher maturation and cleavage rates. Furthermore, the blastocyst development rate in the CNPs25-treated group was significantly higher than that in the CNPs50-treated group, as was the total cell number. Moreover, we found that cloned embryos derived from the CNPs25-treated group showed significantly higher expression levels of Pou5f1, Dppa2, and Ndp52il genes, compared with those of the control and other treated groups. Our results demonstrated that 25 µg/ml CNPs treatment during IVM improves the developmental competence of porcine oocytes by reducing oxidative stress.  相似文献   

Near‐Infrared Hyperspectral Imaging of Fusarium‐Damaged Oats (Avena sativa L.)     

Selamawit Tekle  Ingrid Mge  Vegard H. Segtnan  smund Bj&#x;rnstad 《Cereal Chemistry》2015,92(1):73-80

The feasibility of hyperspectral imaging (HSI) to detect deoxynivalenol (DON) content and Fusarium damage in single oat kernels was investigated. Hyperspectral images of oat kernels from a Fusarium‐inoculated nursery were used after visual classification as asymptomatic, mildly damaged, and severely damaged. Uninoculated kernels were included as controls. The average spectrum from each kernel was paired with the reference DON value for the same kernel, and a calibration model was fitted by partial least squares regression (PLSR). To correct for the skewed distribution of DON values and avoid nonlinearities in the model, the DON values were transformed as DON* = [log(DON)]³. The model was optimized by cross‐validation, and its prediction performance was validated by predicting DON* values for a separate set of validation kernels. The PLSR model and linear discriminant analysis classification were further used on single‐pixel spectra to investigate the spatial distribution of infection in the kernels. There were clear differences between the kernel classes. The first component separated the uninoculated and asymptomatic from the severely damaged kernels. Infected kernels showed higher intensities at 1,925, 2,070, and 2,140 nm, whereas noninfected kernels were dominated by signals at 1,400, 1,626, and 1,850 nm. The DON* values of the validation kernels were estimated by using their average spectra, and the correlation (R) between predicted and measured DON* was 0.8. Our results show that HSI has great potential in detecting Fusarium damage and predicting DON in oats, but it needs more work to develop a model for routine application.  相似文献   

Describing Human–Wildlife Interaction from a European Perspective     

Maria Johansson  Sabrina Dressel  Emma Kvastegård  Göran Ericsson  Anke Fischer  Bjørn P. Kaltenborn 《Human Dimensions of Wildlife》2016,21(2):158-168

European researchers from both the natural and social sciences show growing interest in studying interactions between society and wildlife. A wealth of theoretical frameworks, concepts, and methods are used, but an integration of perspectives is lacking. This research note summarizes results from two workshops that included 63 delegates from 25 European countries, as well as a follow-up survey of 41 respondents. Two main theoretical approaches to the study of human–wildlife interactions were identified. One approach focuses on the collective societal level relying on theories of governance, social representation, deliberative procedures, and commons theory. The other approach targets individuals or groups, and is based on theories such as the cognitive hierarchy, theory of reasoned action, and theory of planned behavior. Interdisciplinary collaboration is needed to identify the best options for wildlife conservation and management in a more politically integrated Europe.  相似文献   

Breeding Restrictions Decrease the Prevalence of Myxomatous Mitral Valve Disease in Cavalier King Charles Spaniels over an 8‐ to 10‐Year Period          下载免费PDF全文

A.C. Birkegård  M.J. Reimann  T. Martinussen  J. Häggström  H.D. Pedersen  L.H. Olsen 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2016,30(1):63-68

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