Identify and genetic analysis on the cryotolerance of overwintering cotton in Nanning, Guangxi

在广西南宁对不同种质来源的棉花材料及其杂交后代进行越冬耐冷性鉴定,为多年生棉花耐冷育种提供基础材料.在开展最佳处理时间和处理温度筛选的基础上,采用5个耐冷生理生化指标(相对电导率、可溶性糖、可溶性蛋白、丙二醛和脯氨酸)和露地越冬指标综合鉴定63份材料的越冬耐冷性,并运用系统聚类的方法将其聚为4大类,即耐冷型23份、中度耐冷型19份、中度冷敏型9份和冷敏型12份,分别占供试材料的36.51%、30.16%、14.29%和19.05%.所有耐冷型材料均和多年生海岛棉种质有关,说明多年生海岛棉在越冬耐冷性育种上具有很高的利用价值.供试棉花材料越冬性的细胞质效应不显著,杂交后代的越冬性有向亲本的平均类型回归的趋势.     

普通野生稻染色体片段代换系的孕穗期耐冷性研究

为筛选出在苗期和孕穗期都具有强耐冷性的种质以供水稻耐冷研究与育种利用,本研究利用人工低温胁迫的方法,对20份苗期耐冷的普通野生稻染色体片段代换系进行了孕穗期耐冷性鉴定评价。结果表明:(1)在20份代换系材料中,孕穗期耐冷性表现强(3级)、中(5级)和弱(7级)级别的材料为2份、15份和3份,分别占供试材料的10%、75%和15%;(2)水稻苗期和孕穗期的耐冷性呈显著正相关(p0.05),所鉴定出的2份抗性3级材料(DC907和DC866)不但可以作为苗期耐冷性抗源,同时也可以作为孕穗期耐寒性抗源;(3)可溶性蛋白、可溶性糖、游离氨基酸、脯氨酸、丙二醛和超氧化物歧化酶等各项生理指标与相对结实率之间均无显著的相关关系,因此均不适宜作为孕穗期耐冷性的鉴定评价指标。     

广西水稻地方品种耐冷性鉴定及相关分析

对419份广西水稻地方品种初级核心种质进行芽期、苗期的耐冷性鉴定及相关分析,结果表明:广西水稻地方品种芽期、苗期耐冷性主要集中在7级和9级,总体耐冷性较弱。芽期、苗期极强耐冷种质(1级)分别为24份和27份,占参试总数的5.73%和6.44%,其中10份种质芽期和苗期均表现极强耐冷(1级)。芽期、苗期耐冷性呈极显著正相关(r=0.66)。粳稻芽期、苗期耐冷性均显著高于籼稻;粘糯稻之间耐冷性差异是由籼粳稻类型的耐冷差异引起的;来自高寒山区稻作区的品种芽期和苗期平均耐冷表现最强。利用34个SSR标记与芽期、苗期耐冷性进行Pearson相关分析,在第7和第9染色体上,各鉴定出1个同时与芽期和苗期耐冷性相关联的位点。本研究为水稻芽期、苗期耐冷育种提供新的抗源材料,并为水稻耐冷基因定位及机理研究奠定基础。     

水稻种质资源芽期耐冷性的鉴定与评价

对新收集的879份水稻种质资源进行了水稻芽期耐冷性的鉴定与评价,从中筛选出芽期耐冷性极强的水稻种质资源39份,均为贵州地方粳稻品种.供试粳稻品种61.23%具有强芽期耐冷性(3级),而籼稻品种只有13.77%具有强芽期耐冷性(3级 ),粳稻品种的芽期耐冷性显著强于籼稻品种.无论籼稻,还是粳稻,贵州地方稻种的芽期耐冷性显著强于来自其他地区的品种,从贵州地方稻种中挖掘极强耐冷种质资源的潜力较大 .     

中国水稻微核心种质不同生育时期耐冷性鉴定及其相关分析

以204份中国水稻微核心种质为试验材料,进行了水稻发芽期、芽期、幼苗期、孕穗期等耐冷性鉴定及其相关性分析。结果表明,水稻各生育时期耐冷性在籼粳亚种间、各种质之间存在明显的差异。粳稻种质的耐冷性明显强于籼稻种质,但籼稻种质中也存在耐冷性较强的种质。高阳淀稻大红芒、肥东塘稻、木樨球、卫国、兴国、山酒谷、中花8号等粳稻种质和包选21号、红米三担白、寸谷糯、红谷等籼稻种质在水稻各生育时期均表现较强的耐冷性,在水稻耐冷性育种及耐冷基因发掘研究中应加以利用。自然低温和冷水胁迫下水稻结实率与低温下发芽率呈显著或极显著正相关,而与死苗率呈显著负相关,即低温下发芽期耐冷性和芽期耐冷性强的水稻种质一般表现为较强的孕穗期耐冷性。认为低温下发芽率和芽期低温处理后的死苗率可以作为孕穗期耐冷性早期鉴定的间接指标。     

中国水稻微核心种质不同生育时期耐冷性鉴定及其相关分析

以204份中国水稻微核心种质为试验材料,进行了水稻发芽期、芽期、幼苗期、孕穗期等耐冷性鉴定及其相关性分析。结果表明,水稻各生育时期耐冷性在籼粳亚种间、各种质之间存在明显的差异。粳稻种质的耐冷性明显强于籼稻种质,但籼稻种质中也存在耐冷性较强的种质。高阳淀稻大红芒、肥东塘稻、木樨球、卫国、兴国、山酒谷、中花8号等粳稻种质和包选21号、红米三担白、寸谷糯、红谷等籼稻种质在水稻各生育时期均表现较强的耐冷性,在水稻耐冷性育种及耐冷基因发掘研究中应加以利用。自然低温和冷水胁迫下水稻结实率与低温下发芽率呈显著或极显著正相关,而与死苗率呈显著负相关,即低温下发芽期耐冷性和芽期耐冷性强的水稻种质一般表现为较强的孕穗期耐冷性。认为低温下发芽率和芽期低温处理后的死苗率可以作为孕穗期耐冷性早期鉴定的间接指标。     

水稻耐冷性鉴定评价方法

水稻耐冷性是我国东北和西南高海拔地区、日本、韩国和朝鲜等国水稻育种的重要研究目标,至今许多学者对水稻耐冷性进行了广泛的研究,并且目前所采用的耐冷性鉴定评价方法已基本成熟,但国内还没有对其进行技术规范化.本文汇总了国内外至今所采用的水稻耐冷性鉴定方法和耐冷指标及分级标准等,将为水稻耐冷性种质资源鉴定和育种以及我国水稻耐冷性鉴定评价技术规范的制定提供参考依据.     

基于过氧化物同工酶分析月季种质资源的亲缘关系及杂种真实性

为了提高种质资源利用率,加速月季育种进程,对27份月季种质及3个杂交组合的8个杂交后代,采用过氧化物酶(POD)同工酶方法分析其亲缘关系并进行杂种真实性鉴定。结果表明:月季种质采用POD同工酶分析具有一定的可行性。酶谱分析中,在相对迁移率为0.264~0.858的位点处共获得7条酶带,其中共有酶带3条,特征酶带4条,表明不同月季种质间遗传多样性丰富,但又存在一定同源性。基于酶带特征进行聚类分析,在相似系数为0.57处,可将27份供试材料分为3个大组。合柱组与月季组材料聚在一个大组中,两个组在形态上的相似性再次得到确认。金樱子与硕苞蔷薇分别聚在两个不同的组中,表明二者之间的亲缘关系较远。供试的古老月季品种被聚在两个不同的大组中,与野生种聚成的一组呈平行关系,表明古老月季在起源上的差异较大,可利用其作为杂交亲本进行广泛杂交以选育具有丰富遗传多样性的杂交后代。根据有无父本特征酶带对杂种后代真实性进行鉴定,初步确定2个杂交组合的6个杂交后代中5个为真实杂种,1个为自交种。该研究结果为进一步开展月季遗传育种奠定了基础。     

基于引物扩增受阻突变技术开发水稻耐冷基因CTB4a特异性分子标记

水稻(Oryza sativa)作为热带与亚热带起源的作物对低温敏感.对水稻种质进行耐冷性鉴定,能筛选出耐冷性强的种质,发展耐冷基因分子标记,能够有效鉴别种质中耐冷基因的基因型.本研究使用芽期4℃低温处理10d对41份水稻材料进行芽期耐冷鉴定,对品种的芽期耐冷能力进行评价,获得了参试材料中除了'昆明小白谷'之外的芽期耐冷性最强的品种'南特号'.对已克隆的耐冷基因CTB4a开发分子标记,能够辅助选择水稻的耐冷育种.水稻孕穗期耐冷基因CTB4a来源于'昆明小白谷',能够影响水稻抵抗低温的能力.参照公布的CTB4a序列信息,从中挑选出序列中的作用位点SNP(单核苷酸多态性,single nucleotide polymorphism),结合引物扩增受阻突变技术(Penta-primer amplification refractory mutation system,PARMS),用Primer 6.0设计引物,建立CTB4a基因荧光分子标记GM-CTB4a,使用荧光分子标记GM-CTB4a对41份水稻品种进行鉴定,使用酶标仪在'昆明小白谷'中检测到利用标记扩增产物中包含'昆明小白谷'特异SNP、T碱基引物携带的FAM荧光信号,在另外40份品种的扩增产物中检测到包含作用位点的C碱基引物携带的HEX荧光信号.本研究利用设计的分子标记,鉴定了 41份水稻品种的耐冷性和基因型.比对分析耐冷性和基因型鉴定结果,说明我们开发的分子标记GM-CTB4a特异性较强,具有实际应用价值.研究结果为利用水稻孕穗期耐冷基因CTB4a培育强耐冷水稻品种奠定坚实基础.     

基于主成分-聚类分析构建甜瓜幼苗耐冷性综合评价体系

为了构建甜瓜(Cucumis melo)种质耐冷性的评价体系并筛选耐冷种质,以19份遗传背景差异明显的甜瓜种质为实验材料,测定低温胁迫下幼苗的9个形态指标和8个生理指标,利用主成分分析、聚类分析及回归分析等多元统计方法对各指标的耐冷系数(α值)进行综合评价。结果表明,低温胁迫下甜瓜幼苗的形态和生理指标发生了明显的变化,其α值的变异系数均大于10%,生理指标的α值变化更为明显。利用主成分分析将原有的17个指标转换为7个独立的综合指标,其累计贡献率达84.64%,以此计算各种质的隶属函数值,并以主成分的贡献率进行加权,最终获得所有种质耐冷性的综合评价值(D值)。基于D值的聚类分析将所有种质按耐冷性强弱划分为3类,其中Oujin为耐冷性最强的种质,Xujin1等11份种质具有中等耐冷性,Qiuxiang等7份种质耐冷性较弱。通过逐步回归分析建立了甜瓜幼苗耐冷性评价的数学模型:D=0.048+0.048POD–0.119SOD+0.097PRO+0.042CRI+0.084RDW+0.206OFW。模型的预测精度大于93.0%。该耐冷性评价体系可广泛用于不同甜瓜种质耐冷性的快速鉴定和预测。     

低酚棉种质资源耐盐性鉴定

为了解决粮棉争地矛盾,棉花向更加盐碱干旱区域发展是大势所趋。因此进行耐盐鉴定筛选抗性种质意义重大。本研究在培养室条件下,利用发芽盒和石英砂对179份来源不同的低酚棉种质资源的耐盐性进行了评价。结果表明,179份低酚棉资源材料中,没有高抗材料;抗盐材料4份,占所鉴定材料的2.2%;耐盐材料54份,占30.2%;盐敏感材料121份,占67.6%。筛选出8份耐盐性突出的材料,其耐盐性达到了耐盐或抗盐的水平,包括豫无424、衡无87-306、中无1651、中无3385、多毛101、中无374-G、中无1038和中无642,这些材料在盐胁迫下的相对成活苗率均在70%以上。国内材料耐盐性好于国外材料,国内材料中河北省、山东省、河南省的材料耐盐性明显好于其他省份。本研究筛选出了耐盐性好的低酚棉材料,为低酚棉育种提供了优异的种质资源。     

Modifying oocytes and embryos to improve their cryopreservation

Numerous studies indicate that in vitro-produced bovine embryos do not survive cryopreservation as well as those produced in vivo. Furthermore, embryos cultured in vitro in the absence of blood serum are more cryotolerant than embryos cultured in media containing serum. Although in vivo-produced embryos are more cryotolerant, there appear to be breed differences. Most if not all of these observations are correlated with cytoplasmic lipid content of embryos; more and larger lipid droplets are associated with reduced cryotolerance. This review concerns strategies for modifying oocytes and embryos to increase cryosurvival. Reduction of cytoplasmic lipid content of embryos with phenazine ethosulfate (PES), a compound that oxidizes NADPH, even improved cryotolerance of bovine embryos cultured in the absence of serum. Whether cytoplasmic lipid content per se or associated changes in lipid composition of cell membranes are responsible for differences in cryotolerance is unknown. Increasing cholesterol content of membranes of sperm and oocytes via cholesterol-loaded cyclodextrin also appears to improve cryotolerance. While lipids have been emphasized and appear to be important, non-lipid aspects of cell composition also likely affect cryotolerance, and might be modified to improve cryotolerance. Additional research on mechanisms of variation in cryotolerance will be applicable to circumvent cryo-intolerance attributable to variation associated with the individual animal, breed, species, cell type, and factors such as nutrition and season of the year.     

Genomic divergence in cotton germplasm related to maturity and heterosis

Commercial varieties of upland cotton(Gossypium hirsutum) have undergone extensive breeding for agronomic traits, such as fiber quality, disease resistance,and yield. Cotton breeding programs have widely used Chinese upland cotton source germplasm(CUCSG) with excellent agronomic traits. A better understanding of the genetic diversity and genomic characteristics of these accessions could accelerate the identification of desirable alleles. Here, we analyzed 10,522 high-quality singlenucleotide polymorphisms(SNP) with the CottonSNP63 K microarray in 137 cotton accessions(including 12 hybrids of upland cotton). These data were used to investigate the genetic diversity, population structure,and genomic characteristics of each population and the contribution of these loci to heterosis. Three subgroups were identified, in agreement with their knownpedigrees, geographical distributions, and times since introduction. For each group, we identified lineagespecific genomic divergence regions, which potentially harbor key alleles that determine the characteristics of each group, such as early maturity-related loci. Investigation of the distribution of heterozygous loci, among 12 commercial cotton hybrids, revealed a potential role for these regions in heterosis. Our study provides insight into the population structure of upland cotton germplasm. Furthermore, the overlap between lineagespecific regions and heterozygous loci, in the high-yield hybrids, suggests a role for these regions in cotton heterosis.     

Estimation of Rhizome Composition and Overwintering Ability in Perennial Sorghum spp. Using Near-Infrared Spectroscopy (NIRS)

Temperately adapted perennial sorghum feedstocks have recently begun to receive increasing interest as candidate energy crops, producing significant biomass and contributing agroecological benefits including increased soil organic carbon, reduced soil erosion, reduced input requirements, and higher net energy return. Rhizomes are the primary morphological feature facilitating overwintering in Sorghum species; however, underlying physiological mechanisms governing rhizome overwintering remain poorly characterized. In this study, we investigated the composition of sorghum rhizomes from diverse germplasm before and after overwintering at two locations and three experimental environments. Significant positive correlations were found between rhizome overwintering and water-soluble carbohydrates, ethanol soluble carbohydrates, and fructan concentrations, while significant negative correlations were found between rhizome overwintering and both crude fat and starch. Near-infrared spectroscopy (NIRS) calibration equations were developed to quickly and efficiently predict the concentrations of each of these assimilates in rhizomes.     

陆地棉品种和骨干品系黄萎病抗性鉴定

选育和推广抗病品种是防治陆地棉黄萎病的主要措施,为了早日实现多类型、多区域大面积抗病品种的应用,本研究选取107份遗传背景差异较大的种质,利用河北省农林科学院棉花研究所小安舍试验站黄萎病病圃进行了3年黄萎病抗性重复鉴定。鉴定得到抗病品系8个,占7.5%;耐病品种(系)20个,占18.7%。本研究表明,当前被作为育种亲本的抗病品系还太少,需要深入开展抗病遗传机制,以及与其他经济性状协同改良的关系,为陆地棉抗病育种提供理论指导;达到抗病或接近抗病水平的大部分品种(系)来自于海陆野远缘后代,具有外源基因血统,证明了远缘杂交是陆地棉黄萎病抗性改良的有效手段。     

棉花种质资源光子性状的遗传分析

文章利用来源于不同国家和地区的102份陆地棉材料和85份海岛棉材料分别与陆地棉遗传标准系TM-1和海岛棉毛子品种新海13号杂交,得到陆地棉和海岛棉两种F₁群体,同时从陆地棉F₁群体中随机选取呈隐性性状的材料"库光子"、"SA65"和"陆无絮"后代,配制3个F₂分离群体,用于进一步研究陆地棉和海岛棉光子性状遗传特征。结果表明:（1）同一材料种植于不同生态区,其种子短绒多少存在变化,新疆和海南要少于安阳,说明棉花短绒多少和生态环境有关系;（2）陆地棉光子材料中26份（25.49%）呈显性遗传,8份（7.84%）呈不完全显性遗传,22（21.57%）份呈隐性遗传;海岛棉光子材料中5份（5.88%）呈显性遗传,16份（18.82%）呈部分显性遗传,9份（10.59%）呈隐性遗传。其余为隐性性状或显性性状不明显材料和毛子材料;（3）库光子的光子性状由两对隐性等位基因控制,并且有互补效应;陆无絮的光子性状由两对隐性等位基因控制,基因间呈积加作用;SA65的光子性状由单隐性基因控制。大量光子材料的初步鉴定为深入研究棉花纤维发育和育种利用提供了基础材料和理论依据。     

姜科花卉种质资源的引种保存、评价与创新

为科学开发利用姜科花卉种质资源,收集84种姜科花卉种质资源进行引种,结合生长情况、观赏特点和经济用途进行引种保存的分析与评价,采用人工杂交育种的方法进行种质创新。结果表明,84种姜科花卉种质资源引种成活了77种,成活率91.7%,成活种类的开花率98.7%,结果率63.6%。生长状况优的种类占59.5%,生长良好的占7.1%,生长中等的占25%,死亡的占8.3%。分布于中低海拔热带亚热带地区的大部分姜科种类能在粤港澳大湾区保存,而分布在热带、中高海拔及特殊生境地区的则不适宜。阶段驯化法可用于引种保存工作;有60.7%的种类为多用途花卉。杂交育种法既可创新种质又可转移保存优良姜科花卉基因。     

Molecular Differentiation of Sexually Incompatible Strains of Agaricus bitorquis Using RAPD and AFLP Markers

Twenty RAPD primers amplified 216 DNA fragments in nine germplasm strains and two newly developed hybrids of Agaricus bitorquis, out of which 98.61% were polymorphic. Six AFLP primer-combinations generated a total of 271 AFLP fragments in nine germplasm strains and six newly developed hybrids, out of which 91.14% were polymorphic. Dendrograms based on UPGMA algorithm and SAHN clustering clearly showed two major phylogenetic groups with both the DNA markers in the germplasm and the hybrids clustered with their parental groups. Genetic similarity between the two groups was 6.52% with RAPD and 18.13% with AFLP markers. Ten most informative primers were identified for initial screening of uncharacterized germplasm using RAPD analysis. Further, AFLP revealed a great power of detection of genetic diversity and validated its usefulness for guiding breeding programmes. The findings are of immediate value to breeders to explore hybridization between genetically diverse parents within the sexually compatible groups. Present study is the first report on the exploitation of AFLP markers in button mushroom for molecular characterization and mushroom breeding.     

Cytological and physiological changes related to cryotolerance in recalcitrant <Emphasis Type="Italic">Livistona chinensis</Emphasis> embryos during seed development

Cytological and biochemical changes in recalcitrant Livistona chinensis embryos following the acquisition and loss of cryotolerance to liquid nitrogen during seed development were studied. The embryonic cells were always hydrated and contained fully functional organelles throughout seed development. However, the central cells in the root-epicotyl end of the embryo exhibited partial dedifferentiation during the middle developmental stages, although extensive reduction of mitochondria and vacuolation and intensive accumulation of starch grains, lipid, and protein bodies were not observed. Total soluble sugar content rose then decreased on a fresh weight and water weight basis, while soluble and heat-stable proteins increased in number and content then decreased, as seeds matured. These cytological and biochemical features differ from those of orthodox seeds, providing a physiological basis for the recalcitrant behavior of L. chinensis seeds. The changes were closely correlated with acquisition and loss of cryotolerance in L. chinensis embryos and are presumed to contribute to cryotolerance, which would account for the cryotolerance variation in L. chinensis embryos. Cryotolerance is suggested to be a complex, multifaceted process, and accumulation of soluble sugars and soluble and heat-stable proteins alone is not enough to increase cryotolerance per se without acting in combination with a decrease of cellular metabolic activity.