Hybridisation with introduced chukars (Alectoris chukar) threatens the gene pool integrity of native rock (A. graeca) and red-legged (A. rufa) partridge populations

The decline of over-hunted red-legged (Alectoris rufa) and rock (A. graeca) partridge populations has been contrasted with massive releases of captive-reared birds, often hybrids with non-indigenous A. chukar. Released interspecific hybrids raise the risks of introgressive hybridisation, and can contribute to further depress the fitness of native populations. Aiming to assess the extent of hybridisation, we genotyped the mtDNA control-region and eight nuclear microsatellites in 671 red-legged, rock and chukar partridges and hybrids, identified by phenotypic traits. Results reveal a diffuse occurrence of hybridisation: (1) 39 samples (6.2%) show mtDNA haplotypes discordant with their phenotypes, indicating red-legged and chukar mtDNA introgression in native rock partridges; (2) admixture analyses of the microsatellite genotypes identified 32 additional rock partridges (5.1%) hybridised mainly with chukars. We analysed also 39 samples collected from a presumed natural red-legged x rock partridge hybrid zone in the French Alps. Surprisingly, 28% birds showed typical chukar mtDNAs, indicating hybridisation with introduced chukars or hybrids. This hybrid zone led to an introgression cline of chukar alleles into neighbouring Alpine rock partridges detectable up to 100 km, which was shorter than expected by neutral genetic theory, and that suggested natural selection against hybrids. These findings indicate that introgressive hybridisation may disrupt local adaptations in natural red-legged partridge and rock partridge populations, and call for strict control of farming and restocking operations.     

开花期干旱胁迫对不同基因型玉米生理特性和产量的影响

以耐旱性不同的3份玉米自交系为材料,在花期进行干旱胁迫处理,研究了耐旱系廊黄和昌7-2与旱敏感系TS141的花期耐旱性差异。结果表明,花期干旱胁迫后,3份玉米自交系的生长受到抑制,地上部和地下部鲜重以及株高下降,枯叶率升高,相对含水量下降,相对电导率升高,渗透调节剂脯氨酸、可溶性糖含量、保护酶SOD和POD活性增加。但是各个指标在不同自交系内变化的幅度不同。与旱敏感系TS141相比,耐旱系廊黄和昌7-2的生长受抑制程度较小;叶片相对含水量下降、相对电导率升高幅度较小;脯氨酸和可溶性糖含量、保护酶SOD和POD活性升高的幅度较大。干旱胁迫后,3份玉米自交系的开花时间间隔（ASI）延长,雄穗一级分枝数减少,产量降低。与旱敏感系TS141相比 ,耐旱系廊黄和昌7-2的ASI延长时间较短,雄穗一级分枝数减少的幅度较小,产量下降幅度较小,特别是单穗重和穗粒数表现更为明显。     

In vitro assessment of the antimicrobial efficacy of chitosan nanoparticles against major fish pathogens and their cytotoxicity to fish cell lines

Nanotechnology is an emerging avenue employed in disease prevention and treatment. This study evaluated the antimicrobial efficacy of chitosan nanoparticles (CSNPs) against major bacterial and oomycete fish pathogens in comparison with chitosan suspension. Initially, the minimum inhibitory concentrations (MIC, MIC₉₀) were determined and the per cent inhibition of bacterial growth was calculated. Subsequently, the minimum bactericidal concentrations (MBCs) were determined. The time-dependent disruptions of CSNP-treated pathogens were observed via transmission electron microscopy (TEM), and the effect of CSNPs on the viability of two fish cell lines was assessed. No antimicrobial effect was observed with chitosan, while CSNPs (105 nm) exhibited a dose-dependent and species-specific antimicrobial properties. They were bactericidal against seven bacterial isolates recording MBC values from 1 to 7 mg/ml, bacteriostatic against four further isolates recording MIC values from 0.125 to 5 mg/ml and fungistatic against oomycetes recording MIC₉₀ values of 3 and 4 mg/ml. TEM micrographs showed the attachment of CSNPs to the pathogenic cell membranes disrupting their integrity. No significant cytotoxicity was observed using 1 mg/ml CSNPs, while low dose-dependent cytotoxicity was elicited by the higher doses. Therefore, it is anticipated that CSNPs are able to compete and reduce using antibiotics in aquaculture.     

新选饲草高粱恢复系农艺性状配合力效应分析

利用5个高粱(Sorghum bicolor)不育系和6个饲草高粱恢复系(IS722为对照)为材料组配置30个杂交组合,采用不完全双列杂交(NCⅡ)设计法对其生物产量、株高、茎粗、分蘖和干重5个主要农艺性状数据进行了遗传力估算和配合力分析。结果表明,所有饲草高粱恢复系中,只有安微草3和053423-2在5个性状上的一般配合力都表现出正向效应,尤其在生物产量等性状上表现出较好的一般配合力。TX623A/053423-2、SX14A/053423-2和SX14A/(MamaMama/BMR)-1等9个组合的生物产量特殊配合力效应值高于对照IS722,表现出较高的特殊配合力。(MamaMama/BMR)-1的株高和干重效应值均位居第1位,表现出较高的一般配合力。V4A/健宝-8-2、HC356A/安徽草3、SX14A/皖系3SM3-1、SX7A/安徽草3和V4A/(MamaMama/BMR)-1在产量性状上表现出较高的特殊配合力,是较好的杂交模式。5个农艺性状的遗传是受加性和非加性效应双重影响,占主导地位的是加性效应。综合而言,(MamaMama/BMR)-1和053423-2表现出的一般配合力突出,安徽草3的特殊配合力表现较好,都是选育出的优良亲本恢复系。本研究对饲草高粱恢复系配合力和遗传力进行了估算,对了解饲草高粱恢复系主要性状的配合力,及为杂交育种选择优良亲本和最优杂交组合提供依据。     

普通野生稻遗传分化及水稻起源关系研究进展

目的研究云南元江普通野生稻及其后代的籼粳属性及籼粳分化程度,为探索普通野生稻的起源演化、遗传分化及育种利用等提供理论依据。方法利用程式指数法和InDel分子指数法从表型到分子水平对云南元江普通野生稻(Oryza rufipogon)、栽培稻合系35号及354份渗入系后代进行粳籼属性分析。结果程式指数法分析结果表明：普通野生稻总分11分,为偏籼型;合系35号总分24分,为粳型;354份渗入系中有籼型材料179份、偏籼型76份、粳型25份和偏粳型74份;经InDel分子指数法鉴定发现：普通野生稻和合系35号的籼型基因频率分别为0.32和0.04,分别属于偏粳型和典型粳稻;在354份渗入系中有典型籼稻113份、籼稻84份、偏籼36份、中间类型29份、偏粳21份、粳稻24份和典型粳稻47份。综合程式指数法和InDel分子指数法分析结果表明：2种方法的拟合度高达92.42%,仅普通野生稻及26份渗入系的籼粳类型划分结果存在偏差。结论程式指数法和InDel分子指数法鉴定稻属资源籼粳属性的结果基本一致,2种方法结合应用可有效分析普通野生稻及其渗入系后代的籼粳属性;普通野生稻籼粳属性在表型和分子水平上存在一定差异,可能与普通野生稻籼粳分化不彻底有关。云南元江普通野生稻渗入系后代的籼粳类型丰富、分化明显,是重要的育种材料,也是研究普通野生稻起源、进化及分类的宝贵资源。     

Mapping of chlorina mutant genes on the long arm of homoeologous group 7 chromosomes in common wheat with partial deletion lines

The chlorophyll a:b ratio of chlorina mutants is much higher than that of wild type plants. Physical mapping of the chlorina mutant loci (cn-A1, cn-B1 and cn-D1) of common wheat (Triticum aestivum L.) and durum wheat (T. turgidum L.) was carried out with partial deletion lines of Chinese Spring(CS) of the long arms of homoeologous group7 chromosomes. F₁ plants of partial deletion lines with near-isogenic lines (ANK-32A and ANK-32B) of the spring bread wheat Novosibirskaya 67 and a near-isogenicline of durum wheat LD222, ANW-7B were evaluated for chlorophyll a:b ratio of the leaves. Hemizygous and heterozygous plants were more easily distinguished by chlorophyll a:b ratio than by visual observation. The dose effects of the chlorina loci on chlorophyll a:b ratio were also confirmed. The position of the allele on the chromosome was localized by fraction length, the comparative values between whole chromosome and partially deleted chromosome. The locus cn-A1 was localized on the region of 83% distal from the centromere on the long arm of chromosome 7A, cn-B1 locus was localized on the region between 69% and 78% distal from the centromere on the long arm of chromosome 7B, and cn-D1 locus was localized on the region between 76% and 77% distal from the centromere on the long arm of chromosome 7D. We consider the map derived by deletion mapping is more accurate than the map calculated from recombination frequency. This revised version was published online in July 2006 with corrections to the Cover Date.     

室内饲养的蠋蝽种群近交衰退分析

蠋蝽是一种优良的天敌昆虫,可以捕食40余种鳞翅目、鞘翅目、膜翅目害虫。目前蠋蝽的规模扩繁大都采用室内饲养方法,因而种群出现了不可避免的近交衰退现象。本研究立足于分析近交繁殖对蠋蝽种群的影响,测定近交繁殖状态下,蠋蝽种群的一系列生命特征,为蠋蝽的规模扩繁提供依据。在室内饲养条件下,连续饲养6代蠋蝽种群,比较近交第6代种群和杂交种群在卵孵化率、各虫态发育历期、重量和性比等方面的差异。近交繁殖第6代种群与杂交种群相比,卵孵化率具有极显著差异,近交种群卵孵化率（43.66%）比杂交种群（66.28%）低22.62%。孵化历期比杂交种群的延长1.7 d。在各龄期历期比较中发现,近交种群的1、2、4和5龄若虫发育历期比杂交种群分别缩短0.29、0.03、0.08和0.51 d,而3龄则延长0.20 d,近交种群若虫发育历期（25.64 d）比杂交种群（26.34 d）短0.70 d。杂交种群各个虫态重量均比近交种群略有增加。在性比方面,近交种群会表现出显著的偏雄性。综上,近交繁殖第6代与杂交繁殖相比,在孵化率与成虫获得率方面显著下降,而在发育历期与各虫态重量方面并无显著差异。因此,在蠋蝽的室内繁殖过程中,应隔一段时间,采集远源虫源进行种群复壮,避免虫源衰退。     

性连锁平衡致死雄蚕品种培育的实践与追求

自引进性连锁平衡致死家蚕基础材料开展雄蚕品种培育至今，已经历了三个阶段，本文对雄蚕品种培育的历程进行了回顾，并对目前育种工作中存在的问题和不足进行了分析，并在此基础上提出了培育雄蚕品种的几点设想。     

神经网络与小型轧机万向接轴的故障诊断

利用神经网络感知器对有裂纹故障小型轧机万向接轴的各阶振动频率进行线性分类，对照不同的分类线可以准确地诊断小型轧机万向接轴的好坏和裂纹深度。     

甜椒雄性不育两用系一代杂种——‘冀研5号’

 ‘冀研5号’是利用甜椒雄性不育两用系AB91 为母本, 以优良自交系JR 为父本配制成的杂交一代甜椒新品种。该品种植株生长势强, 果实长灯笼形, 早熟, 既耐低温弱光,耐热性又好, 连续坐果能力强, 抗病毒病( 抗TMV, 耐CMV) , 较抗炭疽病和疫病, 适宜北方不同类型保护地及露地栽培, 也是理想的南菜北运品种, 一般产量为60 000 kg/ hm²。