基于SRAP分子标记的春大豆杂交种核心亲本杂种优势群划分

为明确杂交大豆核心亲本的遗传多样性特点及群体结构特征,以来源中国东北和国外的100份杂交大豆核心亲本为材料,通过SRAP分子标记多态性分析和UPGMA聚类分析等方法进行聚类分析。结果表明:1)SRAP标记共扩增出2 135条条带,其中多态性条带2 130条,多态性位点占比99.76%,每对引物组合扩增出的多态性谱带数为137~204条,平均为178条,引物的多态性信息含量范围在0.074 0~0.153 7,平均值为0.125 7;2)根据遗传相似系数于0.450 0处划分为2个类群,在遗传相似系数0.460 0处将类群Ⅰ划分2个亚群,又在遗传相似系数0.480 0处将类群Ⅱ划分2个亚群,并将主要来源于中国东北的保持系材料划分为类群Ⅰ,主要来源于美国的恢复系材料划分为类群Ⅱ;3)通过对10个已审定强优势杂交种的13个亲本进行分析发现,杂交种亲本间的遗传相似性多分布在0.329 2~0.637 6;4)通过遗传多样性分析发现,类群I与类群Ⅱ内遗传多样性相似,4个亚群中的亚群Ⅰ-1和Ⅱ-2遗传多样性均大于亚群Ⅰ-2和Ⅱ-1;通过主坐标分析,亲本同样被划分为2个类群,验证了聚类分析的结果。综上,基于SRAP分子标记成功将100份春大豆杂交种核心亲本划分为两大类群;其中,类群Ⅰ的中国东北材料与类群Ⅱ的国外材料之间杂交配制组合存在较强的杂种优势。     

科学地饲喂现代蛋鸡

产蛋鸡,不论是白壳蛋鸡还是褐壳蛋鸡,从遗传上都进行了最高产蛋率的选育,二者的饲喂方案相似,只是由于体重的差异而进行了一定调节.营养学家的任务是从遗传上满足鸡从1日龄至生命结束期间为正常生长发育并获得最高产蛋率的营养需要.由于美国92%的蛋鸡为白壳的,并以海兰W-36为主,Bowen博士将以该品种为例对各阶段的营养需要进行阐述,并提出一些重要的管理建议.     

短梳角野螟的形态描述及幼虫虫龄判断

短梳角野螟Meroctena tullalis(Walker)是为害红花天料木Homalium hainanense Gagnep的重要食叶害虫,其形态描述和幼虫准确分龄是开展害虫生物生态学及林间防控研究的重要依据。本文采用林间采样与室内饲养相结合的方法,首次对短梳角野螟卵、幼虫、蛹和成虫的形态及生活习性和生活史进行调查和描述。并通过测定头宽、头长和体长3项分龄指标,利用SPSS Statistics19.0统计软件对数据进行频次分析,结合戴氏法则和线性回归等试图探究准确划分幼虫虫龄的可靠方法。结果表明:短梳角野螟幼虫随龄期增长,幼虫颜色由浅黄绿色逐渐变为深绿色,头部由肉色逐渐变深,最后形成外围红褐色中间深肉色。通过频次分析统计,测得短梳角野螟幼虫虫龄为5龄;头宽可作为最佳分龄指标,且头宽测量指标平均值自然对数与幼虫龄期呈线性关系(y=0.181 6x-0.602 3,R2=0.999 1)。头长和体长统计检验,符合戴氏法则,但频次分析5个峰值不是很明显,且有部分区域重叠,只能作为划分虫龄的辅助指标。本研究确定了短梳角野螟各虫态的形态特征及划分幼虫龄期的最佳指标,以期为该虫林间防治提供生物学依据。     

Evolution of marine fisheries management in China from 1949 to 2019: How did China get here and where does China go next?

China is the world’s biggest fishing nation and a major player in the global seafood trade. Its fisheries development can decisively influence the global seafood trade, food security and marine conservation. In recent years, significant changes have taken place in China’s fisheries management priorities, policies and regulations. In this paper, we review the evolving fisheries management practices in China to delineate changes in the management policies, methods and their performances from 1949 to 2019. We determined that the following issues impede the development, implementation and enforcement of fisheries policies and regulations, namely the large size of the fishing fleet, large and poorly organized fisheries population, the “hidden” fishing capacity, uniform management approaches that sometimes fail to account for local conditions, lack of clearly defined and allocated fishing rights, limited data quality and availability, insufficient fisheries monitoring programmes, absence of a robust scientific input framework and insufficient stakeholder involvement. Combining those problems with China’s current management initiatives, we propose recommendations for China’s future fisheries reforms. We hope this paper can inform China’s marine fisheries policies and provide valuable references for further researches related to China’s sustainable fisheries management.     

Marker‐assisted backcrossing of a null allele of the α‐subunit of Soybean (Glycine max) β‐conglycinin with a Chinese soybean cultivar (a). The development of improved lines

The development of soybean varieties that lack the β‐conglycinin α‐subunit is an attractive goal because the β‐conglycinin α‐subunit negatively influences the nutrition and gelation of tofu and is a major allergen. To remove this undesirable allergen and simultaneously improve the seed nutritional value and food‐processing quality, marker‐assisted background selection (MABS) was used in backcross breeding to incorporate cgy‐2, a null phenotype version of the gene encoding the β‐conglycinin α‐subunit, from the donor line ‘RiB’ into the genetic background of the Chinese cultivar ‘Dongnong47’ (DN47), a popular high‐oil superfine seed soybean cultivar from Heilongjiang Province, China. In each F₂ (F₂, BC_nF₂) generation of the breeding programme, the offspring that carried the introgressed cgy‐2 were identified by sodium dodecyl sulphate–polyacrylamide gel electrophoresis and rescreened by MABS using simple sequence repeat markers to accelerate recurrent parent genome recovery. Of the 49 advanced backcrossing breeding lines (ABLs), the three best lines, ABL1, ABL2 and ABL3, were selected from the BC₁, BC₂ and BC₃ populations, respectively. The ABLs were evaluated for desirable agronomic characteristics, yield‐related traits, amino acid composition, free amino acid composition and tofu‐processing quality in the mature seeds. All of the ABLs lacked the α‐subunit but grew and reproduced normally without deleterious effects on physiological processes such as seed development and germination. The free amino acid content of ABL1 was significantly higher than that of ‘DN47’, with arginine (Arg) being particularly enriched. Compared to the recurrent parent ‘DN47’, the total protein content of the three ABLs was higher, the amino acid composition of the seed proteins was markedly modified and the yield and hardness of the tofu that was made from the ABLs were significantly increased. MABS combined with stringent phenotypic selection in a backcross breeding programme is a feasible strategy for the genetic engineering of seed protein components to produce allergenic subunit‐deficient variant alleles.     

原油在扰动土壤中入渗的实验研究

随着国家发展对能源的迫切需求,石油作为我国能源的主要构成之一,其开采和冶炼也在不断地增加。然而由于某些相关管理环节的不完善引发的污染事故日趋增多,其中原油的土壤污染问题尤为严重。为研究原油在土壤中的入渗过程,通过室内土柱模拟实验,测定了原油在土壤中入渗的湿润距离、湿润推进速率与时间的关系以及被原油污染的土壤中残留物的含量。结果表明:对于同一质地土壤,随着容重的增加,原油在土壤中入渗的湿润距离、湿润推进速率和残留物的含量均降低;容重相同而质地不同的土壤,随着粉粒含量的增加,原油在土壤中入渗的湿润距离、湿润推进速率和残留物的含量均表现为降低趋势;原油在土壤中入渗的湿润距离随时间的变化可以用对数函数拟合,湿润推进速率与时间的关系可以用幂函数拟合,均达到显著水平。研究原油在土壤中的入渗对于了解原油在土壤中的迁移有着重要的意义。     

An image encryption and compression algorithm based on chaos system and wavelet transform

An image encryption and compression algorithm based on chaos system and discrete wavelet transform (DWT) is studied in this paper.Firstly,four original secret images are transformed by DWT,and then the four low-frequency components are used to compose a two-dimensional coefficient matrix.The matrix is scrambled and encrypted by the chaos system,and then encrypted coefficient matrix is decomposed into four two-dimensional coefficient matrixes.Finally,an encrypted compressed image is obtained by the inverse DWT using the four decomposed two-dimensional coefficient matrices.Encryption and compression are realized at the same time in this algorithm which realizes the combination of chaos and wavelet transform,the experimental simulation and analysis show that the algorithm has good encryption and compression performance.     

Lamprey GnRH‐III Releases Luteinizing Hormone but not Follicle Stimulating Hormone in Pigs

The effect of exogenous administration of lamprey GnRH‐III (IGnRH‐III) on gonadotropin secretion was evaluated in pigs. Six crossbred barrows (82.4 ± 3.5 kg body weight) were assigned randomly to a replicated 3 × 3 Latin square design to evaluate the effect of 0.1, 1.0 or 10.0 μg/kg body weight of exogenous IGnRH‐III on LH and FSH secretion. To facilitate blood collection and infusion of IGnRH‐III, barrows were catheterized in the jugular vein 1 day before initiation of experiments. Blood samples were taken at 10‐min intervals for 6 h, starting 2 h before treatments were applied. Relative concentrations of LH and FSH were calculated by obtaining the ratio of the average concentration of each hormone 2 h after infusion divided by the average concentration during the 2 h before infusion. Relative concentrations of FSH after IGnRH‐III infusion did not influence mean concentration of FSH at any of the doses; yet 10.0 μg/kg body weight had a significant effect on LH secretion (p < 0.01). Relative concentrations of LH averaged 1.2, 1.0 and 3.0 ng/ml (for doses of 0.1, 1.0 and 10.0 μg/kg body weight of IGnRH‐III respectively). Only a dose of 10 μg/kg body weight elicited a significant LH increase that was associated with exogenous IGnRH‐III infusion. We conclude that IGnRH‐III is a weak GnRH agonist and at high doses, IGnRH‐III has the ability to release LH but not FSH in barrows.