云南松主分布区天然群体的遗传多样性及保护单元的构建

以20个云南松天然群体为对象,SSR分析表明云南松遗传变异主要存在于群体内,各群体间的遗传多样性水平差异不显著。基于SSR分子标记遗传多样性分析,根据Nei's遗传相似度,采用逐步聚类优先取样法,分别对初始群体、遗传多样性保护单元和剩余群体进行比较、t检验,以此评价遗传多样性保护单元的代表性。结果表明,利用该方法抽样的群体能很好地代表初始群体的遗传多样性,按30%的群体抽样,等位基因数、有效等位基因数、Shannon's信息指数和期望杂合度的保留率分别达到初始群体的98.03%、105.36%、103.99%和105.56%。保护单元的遗传多样性均高于剩余群体,抽样群体组成的遗传多样性保护单元的效果较好。     

我国食用菌种质资源现状及其发展趋势

对近年来我国食用菌种质资源调查现状和存在问题进行了分析总结,提出了要加大食用菌种质资源调查与保藏的科研投入,加强食用菌种质资源的鉴定评价、创新与利用研究,尽早确定国家知识产权战略,防止食用菌种质资源流失等发展对策.     

甜柿种质资源与育种研究进展

本文概述中国甜柿资源的分布情况,及对全国原生甜柿品种分类进行研究;阐述当前国内外甜柿育种的主要手段,并对未来甜柿育种的研究方向及甜柿产业的发展进行了展望。     

塘四平头种质的遗传改良与利用

自20世纪70年代以来,优质、抗逆、高配合力和适应性广的新种质匮乏,已成为影响玉米商业育种进一步发展的“瓶颈”。生产用种质的遗传脆弱性受到普遍关注,种质扩增、改良与创新成为作物育种研究最重要的发展方向。塘四平头种质对中国玉米育种和生产贡献巨大,因此,玉米育种工作者系统了解、掌握和应用其遗传改良和利用的目标、原则与依据、材料与方法以及途径非常必要,对新世纪继续沿用原有典型的杂种优势利用模式和创建新的杂种优势利用模式奠定基础,具有十分重要的现实意义和深远的历史意义。     

Potential of Nicotiana glauca (Grah.) as a source of resistance to black root rot Thielaviopsis basicola (Berk. and Broome) Ferr. in tobacco improvement

Nicotiana glauca, a wild relative of Nicotiana tabacum, is an attractive potential source of black root rot (Thielaviopsis basicola)‐resistant germplasm. Moreover, it shows a resistance or tolerance to PVY, TEV, anthracnose and powdery mildew. In this study its potential as a source of resistance to black root rot caused by Th. basicola was investigated. Nicotiana glauca GG (2n = 2x = 24) was crossed as male with two N. tabacum TT (2n = 4x = 48) flue‐cured cultivars: ‘BY103’ and ‘K 326’, both of which are susceptible to black root rot. Amphihaploid F₁ TG (2n = 3x = 36), amphidiploid TTGG (2n = 6x = 72) and sesquidiploid TTG (2n = 5x = 60) hybrids were obtained. The resultant sesquidiploid hybrids were used as maternal components in backcrossing to N. tabacum and a segregating post‐sesquidiploid TTg (2n = 5x = 52–54) offspring was obtained. Amphihaploids exhibited a level of resistance to black root rot characteristic of N. glauca. The expression of resistance varied in the sesquidiploid generation, possibly reflecting cytological instabilities in that progeny. A wide variation in response to black root rot was found for post‐sesquidiploids a clear reflection of extensive chromosome segregation in that hybrid generation.     

谷子苗期耐低磷种质筛选及其根系保护酶系统对低磷胁迫的响应

本研究旨在探讨不同基因型谷子苗期耐低磷特性,建立其筛选的评价体系,筛选出苗期耐低磷谷子种质材料。对160份核心谷子种质资源的苗期株高、根长、地上鲜重、地下鲜重、叶长、叶宽、茎粗、地上磷含量、地下磷含量、地上干重和地下干重11个指标的耐低磷系数进行变异分析、相关性分析、主成分分析和聚类分析,采用隶属函数法综合评价不同谷子耐低磷相关指标和耐低磷特性;针对筛选出的低磷敏感和耐低磷品种,在生理水平上分析其根系超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)的活性。结果表明, 9份材料属于低磷敏感品种, 66份材料属于低磷较敏感品种, 70份材料属于较耐低磷品种, 15份材料属于耐低磷品种;低磷胁迫促使谷子根系SOD、POD、CAT活性增加。总之,以综合指标对谷子耐低磷特性的鉴定更为客观;根系保护酶系统对谷子在低磷胁迫下的适应性具有重要作用。     

甘蓝型油菜种子萌发期耐铝毒特性综合评价及其种质筛选

种子萌发是油菜植株形态建成的重要阶段,铝毒是酸性土壤中影响其种子萌发的主要因素之一,因此筛选出种子萌发过程中耐铝毒种质对油菜生产及研究具有重要意义。本研究利用5份甘蓝型油菜品种(系)筛选出油菜萌发期耐铝毒种质资源处理的适宜胁迫浓度为90μg mL~(-1)。并以该浓度处理148份甘蓝型油菜品种(系)种子,于萌发期测定其发芽势、发芽率、鲜重、干重、根长和芽长等指标,通过铝毒胁迫耐性综合评价值(A值)、平均隶属函数值(ASF值)、对铝毒加权耐性系数(WAC值)、相关性、频数、主成分、灰色关联度、聚类和逐步回归分析等鉴定萌发期耐铝性,建立萌发期对铝毒耐性综合评价模型并筛选出适宜的评价鉴定指标。结果表明, 148份甘蓝型油菜的萌发期各指标在品种(系)间存在显著差异;筛选出萌发期耐铝毒甘蓝型油菜品种(系) 01188、WH-20、A109、甲预31棚等。根据灰色关联度及回归分析结果认为,在油菜萌发期测定其根长、芽长、鲜重、发芽率和发芽势,通过回归方程估算其A值,可以初步判断甘蓝型油菜种质的耐铝毒特性。     

Screening for low grain cadmium phenotypes in sunflower, durum wheat and flax

Cadmium (Cd) level in nonoilseed sunflower (Helianthus annuus L.), flax (Linum usitatissimum L.), and durum wheat (Triticum turgidum L. var. durum) grown on uncontaminated, alkaline soils has exceeded limits established in Northern Europe. Separate field experiments were conducted to investigate variability of grain Cd levels among sunflower, durum wheat and flax germplasm, and to seek an efficient screening method for future breeding. There were large variations in leaf Cd concentration among 200 sunflower lines. These lines performed more consistently for Cd uptake at the R5 stage than at the V8 stage across 4 locations with markedly differing soils. Cd concentration in V8 leaves was not related to Cd in grain. The positive correlation between R5 leaf Cd and kernel Cd level was obtained from nonoilseed hybrid (Sigco 954) (R²; = 0.74**), and 200 lines (R² = 0.44**) tested over 4 locations in 2 field trials, respectively. This indicates that an efficient and low cost screening method can be developed for genotype selection, but plants must be grown to the R5 stage. A preliminary evaluation of 30 durum wheat and 74 flax lines indicated large variations in grain Cd level of durum wheat and flax. Grain Cd concentration ranged from 0.11 to 0.34 mg Cd kg^-1 DW for durum wheat, and 0.14 to 1.37 mg Cd kg^-1 DW for flax, respectively. This variability indicates that breeding for low grain Cd in durum wheat and flax should be feasible. This revised version was published online in July 2006 with corrections to the Cover Date.     

甜菜抗褐斑病种质资源的研究现状

甜菜抗褐斑病种质资源是甜菜种质资源中具有褐斑病抗性基因并且能稳定传递给子代的种质资源,是甜菜抗褐斑病育种工作的物质基础,也是农业可持续发展的战略资源。甜菜抗褐斑病种质资源研究的主要内容包括对甜菜品种的收集、鉴定与评价、保存、利用以及抗性遗传基因的克隆及利用。为了使人们更加清晰的了解甜菜抗褐斑病种质资源的研究状况。本文综述了甜菜抗褐斑病种质资源的收集、鉴定与评价、保存、利用及分子方面的研究,并对我国未来种质资源的研究作出展望。以期为以后甜菜抗褐斑病种质资源的研究提供方向。     

峨眉山野生茶树资源农艺性状多样性分析

为挖掘峨眉山野生茶树和群体种中的优良资源,利用因子分析、聚类分析和感官审评等方法,对峨眉山40份野生茶树种质资源农艺性状进行遗传多样性分析和资源评价。结果表明,峨眉山茶树种质资源丰富,且多以灌木型为主;18个芽叶形态性状的变异系数为7.70%~60.99%,变异系数最大的性状是芽叶色泽(60.99%)。因子分析表明,18个芽叶形态性状综合为6个公因子,前6个公因子的特征值大于1且累计贡献率达80.74%,主要代表性指标为叶片大小、叶片锯齿和叶面特征等。聚类分析将研究材料分为5个大的类群,显示了复杂的亲缘关系和丰富的遗传多样性。适制性研究表明,初步筛选的11份种质资源制绿茶适制性较好,感官审评总分在92分以上,大体表现为香气鲜香带花香、清香高长带花香或栗香浓郁带花香,滋味鲜爽、鲜甜或鲜浓醇。