新疆甜瓜品种对两种病害的抗性鉴定

采用人工接菌方法,对新疆的118份甜瓜品种进行抗疫霉病鉴定,113份品种进行抗细菌性斑点病鉴定。未发现高抗和免疫品种。有中抗疫霉病品种3个(发病率38.1%～49.6%),中抗细菌性斑点病品种10个,其他品种均表现轻抗或感病。     

甜瓜白粉病抗源鉴定与抗性遗传分析

在空调温室利用风媒接种方法对从国内外搜集的357份甜瓜种质资源进行了白粉病抗性鉴定，鉴定出69份抗源，其中国外抗源品种有52份；国内种业市场或育种单位搜集的当前推广的品种只有10份抗白粉病；在所鉴定的133份中国薄皮甜瓜和菜瓜地方品种资源中有6份甜瓜和1份菜瓜抗白粉病，表明中国甜瓜地方品种资源中蕴涵着潜在的改良甜瓜白粉病抗性的基因。抗源自交后代抗病株明显多于感病株，初步认为抗源基因的遗传可能表现为显性。     

北京地区番茄晚疫病新菌株致病性鉴定及部分主栽品种与品系的抗性评价

番茄晚疫病是危害番茄生产的重要病害之一。在我国开展番茄晚疫病菌致病性分化研究对番茄抗病品种选育和番茄晚疫病的综合防治意义重大。以往的研究结果表明,番茄晚疫病菌具有明显的生理小种分化现象,且致病性分化变异频繁。2001年,从北京地区采集并获得了一份番茄晚疫病新菌株,以番茄晚疫病菌的5个鉴别寄主品种为材料,采用苗期喷雾接种法对其致病性进行了研究。根据致病性表现初步得出结论,该菌株属于晚疫病生理小种T1.3。同时,利用该菌株对7份番茄一代杂种和10份育种材料接种鉴定表明,7份一代杂种品种均高度感病;而10份番茄育种材料中,7份表现感病或高感病,3份耐病。另外,在2份耐病品系和3份感病材料中均存在一定比例的抗病单株;而两个感病亲本杂交后,其F1抗性明显增强。可见,番茄晚疫病抗性并非简单的由单显性基因控制的遗传模式。     

谷子品种资源抗黑穗病鉴定

连续三年对张家口谷子地方品种共755份进行了抗黑穗病接菌鉴定,筛选出36份对本地黑穗病菌表现免瘦的品种,其中23份对北京和吉林黑穗病菌同时表现免疫。谷子黑穗病菌在其采集地对谷子品种致病力最强。黑穗病抗性基因在谷子杂种一代中以显性出现。     

甜瓜种质资源对疫病的抗性鉴定研究

旨在通过苗期人工接种鉴定,筛选高抗疫病的甜瓜材料,为甜瓜抗病育种以及抗疫病遗传学研究奠定基础。本研究采用灌根接种法,向植株根茎部土壤注入浓度为1×106个/mL的游动孢子悬浮液,对收集到的166份甜瓜材料进行了抗性鉴定,这些材料中有薄皮类型甜瓜41份,厚皮类型甜瓜104份,野生材料15份,近缘种6份。最终筛选到4份免疫材料,25份高抗材料。在供试的厚皮类型甜瓜中有66%的材料抗性水平在中抗及以上,而薄皮类型中有98%的抗性水平是感病或高感。通过相关性分析,发现厚皮类型甜瓜对疫病的抗性要显著高于薄皮类型甜瓜。通过对不同材料的果实性状进行调查,发现在免疫和高抗材料中有14份单瓜重达到1 kg以上,有8份果实可溶性固形物含量在10%以上。这些兼具高抗、高产和高可溶性固形物的材料,可用于抗病基因的定位、克隆等遗传学研究,也可作为育种亲本将抗病基因转移到农艺性状优良但抗性差的甜瓜品种中。     

河南省高粱种质生物学特性的研究

１９８６～１９９０年对河南省高粱品种资源（１０４６份）生物学特性的研究结果表明，苗期抗冷１级品种２９个；苗期抗旱１级品种１６个；苗期和芽期均耐盐的品种８个；发病率在１２％以下抗丝黑穗病品种８个；抗螟１级品种９个；耐瘠１级品种８０个。品质分析结果：蛋白蛋含量１４％以上的品种７个；赖氨酸占蛋白含量２．６％以上品种１４个，赖氨酸占样品含量０．３％以上品种２２个，其中赖氨酸占蛋白、占样品均高的品种５个；单宁含量低于０．１％的品种１９个；具２个和２个以上优异性状的种质１２个，其中具３个以上优异性状的高粱种质２个，这些高粱品种资源是最宝贵的种质材料。实践证明，利用生物措施是稳定提高农业生产的有效措施。目前河南省推广面积较大的高粱品种多是抗性中上等，丰产性、品质较好的品种。     

冬小麦品种抗、感白粉病性能变异动态研究

１９９３～１９９８年对河南省１３个主栽冬小麦品种白粉病的系统调查和抗性鉴定及评价结果表明：①河南主栽冬小麦品种中没有对白粉病免疫的品种,发病最重的是豫麦１３号,平均病指２８．９,平均ＡＵＤＰＣ值５０２;发病最轻的是郑州８３１,平均病指２．３,平均ＡＵＤＰＣ值２５。②感、抗白粉病性没有明显变异的品种占总数３８％,有明显变异的品种占６２％,其中,高感变中感的品种１个（西安８号）,中感变高感的品种１个（     

不同向日葵品种资源对黄萎病抗性的田间鉴定

在内蒙古巴彦淖尔市五原县、宁夏固原县以及黑龙江农科院农场的田间自然病圆进行了不同向日葵品种杭黄姜病鉴定试验。结果表明,同一供试地点不同向日葵品种之间以及同一品种在不同供试地点间均存在着一定的杭性差异。内蒙古巴彦淖尔市五原县供试的48份向日葵品种中鉴定出高杭品种10份,中杭品种10份,感病品种28份;宁夏固原县供试的30份向日葵品种中鉴定出5份高杭黄萎病的向日葵品种,中抗黄姜病品种12份,13份感病品种;黑龙江农科院供试的52份向日葵品种中鉴定出1份免疫品种PR2302,高杭品种8份,中抗品种14份,感病品种30份。同时,不同供试地点的试验结果表明,同一向日葵品种在不同供试地点对黄姜病杭性表现出一定差异,预示着向日葵黄姜病菌存在着致病力分化现象。     

河北省和北京地区小麦白粉病菌寄主范围研究

用小麦白粉病菌１１个生理小种的混合菌种，对采自河北省和北京地区１２个市、县的小麦近缘植物的４个属，１２个种的６２份材料进行接种，除８份免疫外，其余均接种成功。用其中４个属，１２个的４９份材料产生的白粉病菌对小麦进行回接，亦全部回接成功，小麦白粉病菌生理小种对小麦近缘植物的寄生，像在小麦上一样，有明显的寄生专化性。８２．２％的感病小麦近缘植物其感病性随生育期增长而急剧下降。文中还讨论了小麦近缘植物在     

抗白粉病月季资源的田间筛选

筛选抗白粉病月季资源对月季栽培利用及抗病育种品种的选择有重要意义。对保存的来自国内外不同地区、不同类型的349份月季资源进行了田间筛选。供试品种病情分为高抗、抗病、中抗、感病、高感5个等级。供试品种对月季白粉病抗性表现比较分散。月季抗病资源182份,占供试品种的52.15%,其余167份均表现为感病,占47.85%,其中抗病资源中有13份表现为高抗,占供试品种的3.72%;349份资源中包括27份中国古老月季,其中有11份表现为抗病,占中国古老月季的40.74%。抗白粉病月季资源的筛选能够为月季栽培、育种亲本品种的选择提供参考。     

Landraces: A review of definitions and classifications

The first reference to landraces as genetic resources dates from 1890. Some 20 years later the first definitions of a landrace were published. In the period 1909–1952 several definitions of the term landrace have been presented. No definitions were discovered in articles published in the period 1953–1974. The reason could be that after the Second World War attention of plant breeders and others was focussed on making instant progress. New definitions have been presented since 1974. Genetically related landraces form a landrace group. Synonyms of the term landrace and landrace group as cited in the literature are also given. The classification of types of landraces given by Mayr in 1934 had been discussed and an amended classification provided, paying attention to contamination caused by seed change. As a landrace has a complex and indefinable nature an all-embracing definition cannot be given. However, I suggest the following: an autochthonous landrace is a variety with a high capacity to tolerate biotic and abiotic stress, resulting in a high yield stability and an intermediate yield level under a low input agricultural system. This revised version was published online in August 2006 with corrections to the Cover Date.     

Diversity and population structure of black soybean landraces originating from Tanba and neighboring regions

Black soybean landraces that had been cultivated in Tanba region and the neighboring regions and conserved black soybean landraces, including those from other regions in Japan, were used in this study. The polymorphisms of 78 SSR markers in nuclear DNA and 6 SSRs in chloroplast DNA were analyzed in the black soybean landrace populations. The result of phylogenic analysis revealed that the black soybeans can be classified into six clades. The landraces originating from Tanba region were classed into first and second clades, and two chloroplast genotypes were found in the population of black soybeans from the Tanba region. Genotype A chloroplast was predominantly identified in major populations of the Tanba, while genotype B was widely distributed in the black soybean population. Population structure analysis in the Japanese black soybean accessions inferred there are six groups. The black soybean landrace from the Tanba region was classified into three groups, mainly corresponding to the distance-based phylogenic results. The two groups were probably derived from different ancestors with Type A and B chloroplast genomes, respectively, whereas the other group showed both types of chloroplast genome. The admixture situations suggested that the landraces in the main group have been widely cultivated in Tanba region, while the landraces that belong to other groups were cultivated in localized area. Several phenotypes were compared among genotype groups, dividing into two sub-groups: founder sub-group and admixed sub-group. Phenotypic differences were observed between founder landraces in group 1 and group 3. On the other hand, landraces in admixture landraces in group 1 and group 2 segregated for several traits, while founder landraces in group 1 were stabled for each trait. These observations suggest that gene flow events have occurred between different founder landraces.     

河北水稻地方种质品质多样性分析

为了揭示河北水稻地方种质资源品质性状遗传多样性,采用多样性指数、主成分分析、聚类分析等方法对收集的109份河北水稻地方种质15个品质性状进行了遗传多样性评价。结果表明：河北水稻地方种质存在丰富的遗传多样性。15个品质性状平均变异系数为23.03%,平均多样性指数为1.92。垩白粒率、垩白度、粒长、蛋白质含量、米饭硬度5个性状多样性指数大于2,表明这些河北水稻地方种质在这些性状上遗传变异丰富。根据主成分分析,15个品质性状可归纳成为4个主成分因子,其累积贡献率包含了15个变量83.04％的信息。米饭食味、直链淀粉含量、精米率、垩白度是影响河北水稻地方种质品质的主要因素。采用4个主成分因子欧式距离聚类分析结果表明,在遗传距离D=16.5处,可以将109份地方种质分为4类,但不同来源的河北地方水稻种质交错分布聚类。本研究为河北地方水稻种质的利用提供了科学依据。     

Line selection for exploiting durum wheat (T. turgidum L. var. durum) local landraces in modern variety development program

Summary Pure line selection for grain yield applied within four durum wheat local landraces (Triticum turgidum L. var durum) was studied in an effort to determine: (i) the agronomic performance of selected line mixtures (bulks) and their value as potential new cultivars, (ii) the effectiveness of pure line selection for grain yield within local landraces and (iii) the correlated selection response of yield components and kernel quality traits. Four local durum wheat landraces were used. Two of them, Mytilini-1 and Mytilini-2 are still cropped in some rural areas of the island Mytilini whereas the other two, Limnos and Mavragani are maintained in the Greek Gene Bank. Following their preliminary evaluation for agronomic performance under current growing conditions, 100 individual plants from each landrace were randomly selected. Selected plants (pure lines) were field evaluated head to row during 1997–98 and 1998–99 growing seasons. Based on grain yield performance, bidirectional selection, high vs low, was practised within each landrace. Thus the five higher yielding lines and their corresponding lower ones from each landrace were identified. Selected lines, with no further progeny testing, were pooled using a balanced seed composite to form the high yielding five line bulk and its respective low counterpart. The resulting 16 bulks (eight high and eight low) along with their four source landraces and two commercial varieties, Mexicalli and Simmeto, used as checks, entered field testing for agronomic performance in two and one location during 1999–00 and 2000–01 growing seasons respectively. Data for grain yield and yield components (1000 kernel weight, number of kernels, and productive tillers) along with kernel quality data (protein content and vitreous) were recorded. Data for grain yield indicated that the landraces studied seemed to be line mixtures, as expected, since they responded to bidirectional phenotypic pure line selection. The high yielding bulks were of interesting agronomic performance, equivalent to or significantly better than that of the commercial checks and are worth further testing as potential cultivars. Selected high bulks of Mytilini 2 landrace significantly outyielded both the source landrace and the commercial checks maintaining the high protein content of the source landrace, which was significantly higher than checks. This performance provides evidence that the within landraces selection of lines combining high grain yield with high protein content seems to be feasible. In conclusion, evidence is presented that genetic variability seems to be available within the landraces studied which could be worth using in breeding programs. Furthermore the simple pure line selection breeding effort undertaken seemed to be effective in developing line bulks with promising performance and worth further testing as potential cultivars.     

Genetic variation of melon (C. melo) compared to an extinct landrace from the Middle Ages (Hungary) I. rDNA, SSR and SNP analysis of 47 cultivars

Summary Microsatellite profiles of 47 melon cultivars and landraces were analyzed and compared to the aDNA (ancient DNA) of seed remains from an extinct sample recovered from the 15th century (Budapest, Hungary). An aseptic incubation followed by ITS (internal transcribed spacer) analysis was used to exclude the exogenously and endogenously contaminated medieval seeds and to detect SNPs (single nucleotide polymorphism) in ITS1-5.8S-ITS2 region of rDNA (ribosomal DNA). SNPs were observed at the 94–95 bp (GC to either RC, RS or AG) of ITS1; and at 414 bp (A-to-T substitution), 470 bp (T to Y or C), 610 bp (A to R or G) and 633 bp (A-to-G transition) of ITS2. For comparative microsatellite analysis SSRs (simple sequence repeats) detected by ALF (automated laser fluorometer) was used. Eight of the 20 SSR primer pairs amplified 40 microsatellite alleles in identical fragment ranges. A total of 485 alleles were detected in the 47 melon cultivars. The number of alleles per marker ranged from 2 to 7 with an average of 5.7 including CMCT44 (2 alleles), CMAG59 (5 alleles), CMGA104 (5 alleles), CMCT134 (4 alleles), CMTA134 (6 alleles), CMCTT144 (7 alleles), CMTC168 (6 alleles) and CMCT170 (5 alleles). Sequence analysis of the microsatellite alleles showed different fragment lengths depending on changes in the number of unit of core sequences. Dendrogram produced by SPSS11 based on the presence versus absence of SSR alleles revealed that medieval melon had the closest genetic similarity to a registered melon cultivar Hógolyó selected from an old Hungarian melon landrace. These results also indicated that cloned DNA sequences recovered from aDNA of medieval melon can be of use for molecular breeding of modern melon cultivars via gene transfer.     

Genetic diversity analysis of Moroccan lentil (Lens culinaris Medik.) landraces using Simple Sequence Repeat and Amplified Fragment Length Polymorphisms reveals functional adaptation towards agro‐environmental origins

In the absence of previous molecular characterization, we assessed genetic diversity of 53 Moroccan lentil landraces including two local cultivars using simple sequence repeat (SSR) and amplified fragment length polymorphisms (AFLP). Nineteen SSRs yielded 213 alleles, and seven AFLP primer combinations gave 766 fragments of which 422 were polymorphic. Moderate to high genetic variation was observed. Several small groups of landraces were differentiated. Interestingly, one of the smallest groups contained short‐cycle landraces with high early vegetative growth. Landraces in that group were from the dry land location of Abda, where they were likely selected for adaptation to drought and heat stress over centuries. Another group contained two landraces from highland areas that may have been selected for specific adaptation to cold stress. A third group contained one landrace from the Zear region known for its seed quality and has been proposed for the protected designation of origin (PDO) quality mark. Both techniques gave evidence of differentiation of the latter landrace supporting the idea of PDO attribution. Functional grouping according to agro‐environmental origins, cycle duration and early vegetative vigour was observed.     

Farmers' seed management practices open up new base populations for pearl millet breeding in a semi-arid zone of India

Farmers in western Rajasthan (north‐west India) produce and maintain their landrace populations of pearl millet through their own distinct seed management practices. The objective of this study was to characterize morphological and agronomic variability of different traits between and within three farmers' populations using quantitative‐genetic parameters. Populations examined were a typical landrace and two modified landraces, which were generated through farmer introgression of modern varieties with different levels of subsequent selection. From these three populations, 100 random full‐sib progenies were evaluated in field trials at two locations in western Rajasthan over two years. Significant genetic variation existed within the three populations. Estimates of heritability were moderate to high for all observed traits. Predicted selection response for grain yield across environments was 1.6% for the typical landrace and 2.2% for both the modified landraces. Results suggest that the introgression of modern varieties into landraces had increased the genetic diversity. Therefore, farmers' current breeding activities could open up new resources for plant breeding programmes aiming at plant improvement for the semiarid zones of India.     

Utility of pearl millet landraces in breeding dual-purpose hybrids for arid zone environments of India

In pearl millet (Pennisetum glaucum (L.) R. Br.), single cross hybrids based largely on exotic germplasm, have found very limited adoption in drought-prone arid regions mainly due to their inadequate adaptation to prevalent extremely harsh agro-climatic conditions. This study tested the hypothesis that the use of restorer parents derived from adapted landrace germplasm could be an alternative strategy in developing suitable hybrids for arid regions. Forty inbred restorer lines developed from two phenotypically diverse landraces were used to develop hybrids evaluated in this study for their performance in five typical arid zone environments between 2003 and 2007. Inbred lines from both landrace populations differed significantly in their combining ability for biomass, harvest index and grain and stover yields. A larger proportion of experimental hybrids, based on selected inbred lines, significantly outperformed the commercial checks for grain and stover yields. Increase in grain and stover yields was achieved primarily due to their higher biomass productivity, with no decline in harvest index. Choice of landrace determined the relative grain and stover productivity of their hybrids. Phenotypic differences observed in parental landraces in tillering and panicle length were also visible in their respective hybrids, indicating that characteristics of landrace parental populations were transmitted in their hybrids.     

Variation for resistance to Puccinia hordei in Ethiopian barley landraces

Summary Up to 100 single plant derived lines of 18 Ethiopian barley landraces were evaluated for infection type in the seedling and adult plant stage, and for latent period in the adult plant stage only. A low infection type indicates the presence of race-specific resistance genes of the hypersensitive type, while the latent period is the major component of the polygenic, partial resistance.In the seedling stage 1721 of these single plant derived landrace lines were assessed for infection type against two barley leaf rust races. In the adult plant stage 1227 from these 1721 lines were evaluated for infection type against one race. In the seedling stage 2 (against race 1-2-1) and 29 against race A) out of the 1721 lines showed an infection type lower than 6–7 on the 0 to 9 scale. In the adult plant stage none of the 1227 lines had an infection type lower than 6–7 against race 1-2-1.The variation between and within the landraces for latent period in the adult plant stage was large. Some landraces such as landrace 212845 showed a highly significant and longer mean latent period than most other landraces. Virtually all plants in all landraces carry at least some partial resistance.The near-absence of race-specific, major, resistance genes and the high frequency of moderate levels of partial resistance indicates that the durability of leaf rust resistance in Ethiopian barley landraces is due to the latter type of resistance, and that the multiline principle does not operate.