棉田残膜回收机械研究现状及发展趋势

棉花地膜覆盖栽培技术提高了水分的利用率和棉花的产量,随着地膜的连年使用,棉田残膜含量不断增加,已造成严重的“白色污染”,影响棉花的种植和产量。PE地膜被替代前,机械化回收是解决残膜污染的必要手段。通过对残膜回收机械的起膜装置、拾膜装置、脱膜装置、集膜装置、清杂装置等方面介绍残膜回收机械的研究现状和特点。分析棉田残膜回收机械的应用情况,存在耕层残膜回收率低、膜杂分离效率低、作业部件适应性不强、作业质量不稳定等问题,针对残膜、秸秆、土壤的特性和生产实际,提出研发全耕层地膜回收机具、改进膜杂分离装置、创新作业部件仿形技术、提高智能监控水平的研发方向。     

6个牛品种在FSHR基因位点的遗传关系及其多态对双胎性状的标记

用PCR-RFLP技术,对秦川牛、中国荷斯坦牛、晋南牛、南阳牛、延边牛、中国西门塔尔牛6个牛品种176个个体的促卵泡素受体(FSHR)基因5′端进行多态性分析,4种内切酶对PCR产物的单酶切结果发现,Pst ,Sin 和Hae 3种内切酶的酶切产物均为单态,而Taq 的酶切产物出现多态性,表现为3种基因型(AA,BB,AB),品种间基因频率和基因型频率均有较大差异。对3个有单双胎记录牛的品种分析发现,秦川牛双胎母牛的等位基因A(0.5500)及基因型AA(0.5000)的频率高于单胎母牛(A:0.3500,AA:0.3000);而荷斯坦牛双胎母牛的等位基因B(0.5937)及基因型BB(0.6875)的频率均高于单胎母牛(B:0.5416,BB:0.4167),在后代中有同样的趋势;在中国西门塔尔牛的双胎母牛、随机母牛及种公牛3种类群中,双胎母牛和种公牛的等位基因B(0.5909,0.5417)和杂合子基因型AB(0.8182,0.9167)的频率高于随机母牛(B:0.3182;AB:0.4546)。根据Nei氏标准遗传距离聚类分析,表现为西门塔尔牛和延边牛首先聚在一起,然后晋南牛、秦川牛、荷斯坦牛、南阳牛依次加入。     

Genetic screening of FecB,FecXG and FecXI mutations and their linkage with litter size in Barki and Rahmani sheep breeds

Characterization of fecundity genes offers the opportunity to improve production efficiency, and the consequent increase in litter size in livestock industry, through utilizing them in breeding programs. The main objective of this study was to detect the BMPR‐IB, BMP15 and GDF9 gene mutations and to investigate whether these mutations are associated with litter size in Egyptian sheep breeds. To achieve this goal, 73 adult ewes representing Barki (n = 33) and Rahmani (n = 40) breeds were used. Polymerase chain reaction–restriction fragment length polymorphism (PCR‐RFLP) screening approach was used to detect the presence of FecB, FecX^G and FecX^I mutations in the two selected breeds. Results of this study showed that the three different candidate gene mutations, namely FecB, FecX^G and FecX^I are not present among these selected populations of the Egyptian breeds. Further studies regarding other mutations and/or other genes, which may influence ovulation rate, should be carried out to determine the type and mode of inheritance of such genes in Egyptian sheep breeds.     

抑制素基因免疫诱导单胎绵羊孪生的研究

应用抑制素基因免疫重组质粒 (PCIS)免疫绵羊 ,首次免疫后 ,绵羊能够产生抗抑制素抗体 ,加强免疫后抗体增加显著 (P <0 0 5 ) ,免疫羊的抗体阳性率可达 4 6 7%。免疫组与对照组促卵泡素 (folliclestimutatinghormone ,FSH)的含量在加强免疫第 4 5天时差异显著 (P <0 0 5 )。在首次免疫第 2 0天与加强免疫第 4 5天 ,抗体阳性羊的促卵泡素含量显著高于抗体阴性羊 (P <0 0 5 )。免疫羊的双羔率达 39 2 % ,显著高于对照组 (P <0 0 5 ) ,比对照组提高 2 9 2 %。     

人工授精+胚胎移植(AI+ET)法诱发肉牛双胎的试验研究

应用AI ET法分别对3组试验牛处理,人工诱导生产肉牛双胎,双胎率达60.8%(79/130),产犊率147.7%(192/130).其中试验组Ⅱ(自然发情后AI ET)双胎率达66%(33/50),产犊率150%(45/30),显著提高了母牛的繁殖率.