Geographical variation of β-amylase thermostability among varieties of barley (Hordeum vulgare) and β-amylase deficiency

Investigations onto the thermostability of β-amylase in 274 varieties of barley (Hordeum vulgare L.) indicated that all varieties except one were distributed into three types of high (type A), intermediate (type B), and low (type C) thermostability, respectively. One variety (TB29) from China showed no β-amylase activity. Geographical variation was observed in the thermostability of β-amylase. Type C varieties were not observed in East Asia (Japan, the Korean Peninsula, China and Nepal), although 36 out of 37 varieties in Ethiopia were type C. Most of the varieties were Type A in Japan, the Korean Peninsula and China, whereas the frequency of type A and type B were nearly equal in Nepal. Varieties in the other five areas (North America, North Africa, Southwest Asia, Turkey and Europe) consisted of types A, B and C. These results support the fact that East Asian cultivars are genetically different from those of the western regions, as previously reported.     

Wide compatibility in rice (Oryza sativa L.)

Summary Wide compatible varieties (WCVs) show normal spikelet fertility in crosses with Indica and Japonica rice varieties. Crosses of Indica and Japonica varieties frequently show high spikelet sterility which prevents exploitation of heterosis for grain yield. We screened 41 rice varieties for the wide compatibility trait by crossing each with three Indica and three Japonica testers. Varieties giving fertile F₁ hybrids with both groups of testers were classified as WCVs. Seven varieties viz., BPI-76 (Indica); N 22; Lambayeque-1 and Dular (Aus); Moroberekan, Palawan and Fossa HV (Japonicas), were identified as WCVs. The frequency of WCVs was higher among Aus and Japonicas. The wide compatibility trait in varieties: Dular and Moroberekan was controlled by a single dominant gene linked with the Est-2 and Amp-3 loci (mean recombination 32.0%). Est-2 and Amp-3 showed complete linkage. Pgi-2 was found to be linked with Est-2 and Amp-3 (mean recombination 16.1%). Est-2 and Amp-3, showed a tighter linkage with C ⁺ (mean recombination 4.1%). Pgi-2 showed a lower linkage with C ⁺ (mean recombination 17.3%). The recombination values between the WC gene in Dular and C ⁺ was much higher than those reported in Japan for the WC gene (S₅ ⁿ) from Ketan Nangka. It is possible that the WC gene from Dular is different from that in Ketan Nangka. Linkage intensities with the WC gene were not strong enough to be of use for indirect selection for the wide compatibility trait. A search for a more closely linked isozyme or DNA marker was proposed.     

Molecular characterization of South and East Asian melon, Cucumis melo L., and the origin of Group Conomon var. makuwa and var. conomon revealed by RAPD analysis

The genetic diversity and relationship among South and East Asian melon Cucumis melo L. were studied by using RAPD analysis of 69 accessions of melon from India, Myanmar, China, Korea, and Japan. The genetic diversity was large in India, and quite small in Group Conomon var. makuwa and var. conomon from East Asia, clearly indicating a decrease in genetic variation from India toward the east. Cluster analysis based on genetic distance classified 17 groups of accessions into two major clusters: cluster I comprising 12 groups of accessions from India and Myanmar and cluster II that included five groups of accessions of Group Conomon var. makuwa and var. conomon from East Asia. Cluster I was further divided into three subclusters, of which subclusters Ib and Ic included small- and large-seed type populations, respectively. Therefore, this division was based on their seed size, not cultivation area. The large-seed type from east India was differently included in the subcluster of small-seed type (Ib). A total of 122 plants of 69 accessions were classified into three major clusters and subclusters: clusters I and II comprised melon accessions mostly from India and Myanmar, and cluster III comprised Group Conomon var. makuwa and var. conomon from East Asia. The frequency of large- and small-seed types was different between clusters I and II, also indicating genetic differentiation between large- and small-seed types. One plant of the small-seed type from east India was differently included in cluster III, and two plants from east India were classified into subcluster IV. These results clearly showed that South Asian melon is genetically differentiated by their seed size, and that small-seed type melon in east India is closely related to Group Conomon var. makuwa and var. conomon.     

Morphological Classification of Traditional Philippine Upland Rice Cultivars in Upland Nurseries Using Cluster Analysis Methods for Recommendation, Breeding and Selection Purposes

Using eight morphological parameters with six cluster analysis methods, a set of 21 traditional and four improved Philippine upland rice cultivars (cvs) could be separated into five groups: (1) improved semi-dwarf plant type, (2) improved or 'moderately modified' (short) Indica plant type, (3) traditional tall Indica plant type, (4) traditional tall Japonica plant type and (5) traditional short Japonica plant type. The results emphasized the importance of the separation into Indica and Japonica plant types, but the cultivars could be classified more accurately using growth characteristics such as tillering ability, followed by plant height and leaf area parameters. The clusters containing Indica cvs consistently showed a higher tiller number per plant, a higher growth stage (DC classification) and narrower leaves than clusters with Japonica cvs. The parameters culm length, plant height, leaf area, leaf length and width were represented in subgroups with both long and short expression of the respective characteristic. Use of the existing variability of morphological traits within the group of traditional upland rice cvs should be beneficial in recommendation, breeding, selection and development of upland rice cvs for the different rice ecosystems as well as for the upland rice/rice blast pathosystem.     

Genetic variation in resistance to blast disease (Pyricularia oryzae Cavara) in Japanese rice (Oryza sativa L.), as determined using a differential system

A total of 324 Japanese rice accessions, including landrace, improved, and weedy types were used to 1) investigate genetic variations in blast resistance to standard differential isolates, and 2) across the genome using polymorphism data on 64 SSR markers. From the polymorphism data, the accessions were classified into two clusters. Accessions from irrigated lowland areas were included mainly in cluster I, and upland and Indica types were mainly in cluster II. The accessions were classified into three resistance subgroups, A2, B1 and B2, based on the reaction patterns to blast isolates. The accessions in A2 were postulated to have at least two resistance genes Pish and Pik-s, whereas those in B1 had various combinations of the resistance genes Pish, Pia, Pii, Pi3, Pi5(t), and Pik alleles. The B2 accessions were resistant to almost all isolates, and many accessions of cluster II were included, and had Pish, Pia, Pii, Pi3, Pi5(t), certain Pik, Piz and Pita alleles, and unknown genes. The frequencies of accessions of B1 originating in Hokkaido, and those of B2 originating in the Kanto and Tohoku regions were remarkably higher than in the other regions.     

21个稻瘟菌株毒力与42个水稻品种抗瘟性的系统聚类分析

通过对42个水稻品种进行人工离体叶片接种,明确供试水稻品种对21个稻瘟菌株的抗普和病级并在此基础上对42个水稻品种抗瘟性作了初步研究。分别按供试21个稻瘟菌株毒力差异和42个水稻品种抗瘟性的多个抗性指标进行系统聚类分析。将供试稻瘟菌株分为七类,其菌株毒力差异显著,菌株毒性频率和平均毒力之间呈现高度负相关。把水稻品种分为七类,其中第三类的第一组抗性最好,抗普在85%~100%,病级4.0以下。结果对选育水稻抗瘟新品种、合理布局区内抗性水稻和防治稻瘟病爆发具有一定的实际意义。     

谷子品种遗传差异的RAPD标记分析

利用RAPD标记对来自春、夏谷区不同育种单位的23份谷子品种进行了多态性和聚类分析。结果表明,23份品种的RAPD标记的多态性较低,13个引物共扩增出56条多态性带,平均每个引物扩增多态性带为4.31条,引物S30和S45都有7条多态性带,能够鉴别的品种最多为13个。聚类分析表明,当遗传相似性系数为0.75时,23个品种可分为4类,不同生态区的品种可以归为一类,而同一生态区的品种也可以归为不同的类,基于RAPD的遗传相似性和品种来源地没有必然的一致性。     

Analysis of Vietnamese rice germplasm provides an insight into Japonica rice differentiation

Genetic differentiation among landraces of rice in northern Vietnam that lie in the centre of genetic diversity of Asian cultivated rice was analysed using DNA markers, and morphological and physiological traits to obtain an insight into the genetic differentiation of Asian rice. Principle coordinate analysis, based on nuclear RFLP data, divided Vietnamese rice varieties into three groups, designated A, B and C. Chloroplast DNA variation discriminated group A, which corresponded to the Indica rice varieties, from both groups B and C, which corresponded to the Japonica rice varieties. Physiological characteristics for Indica‐Japonica and tropical‐temperate Japonica discrimination suggested groups A and B consisted of typical Indica and Japonica varieties, respectively, while the characteristics of group C were distinct from those of the other two groups. This suggests that the genetic differences between groups B and C represent a new aspect of genetic variation that has not been previously reported in Japonica rice. Groups C and B corresponded with upland and lowland rice, respectively. Eight marker loci were associated with upland‐lowland differentiation in Japonica rice. Highlighted chromosomal regions might have been selected during the history of cultivation under different cultural conditions, and thus contain genes related to adaptation.     

稻瘟病抗性基因Pita在中日韩粳稻中的分布

为了解2 350份来源中国、日本和韩国粳稻品种(系)稻瘟病抗性基因Pita的分布,利用2个KASP分子标记对该基因进行了检测,605份材料表现有利,1 732份不利,7份为杂合,6份不确定。在有利、不利和杂合三个群体中分别随机选取316份、101份和7份材料,对Pita基因功能片段进行了测序分析,结果显示有利群体中KASP检测结果准确率为95.89%,不利群体100%,2个KASP分子标记可以用来联合检测水稻种质资源的Pita抗性基因。根据KASP分子标记检测结果,在中国北方地方稻种中仅0.69%品种携带Pita抗性基因,在中国13个省区市育成品种(系)和日本韩国外来稻种中均有一定的分布,频率7.02%~55.81%,表明Pita基因在东亚地区范围内均得到了一定的应用,但各地区应用程度相差较大,其中中国吉林、辽宁、宁夏、浙江四省地区较高。通过415份材料Pita基因功能片段609个碱基序列的比较,仅发现3个变异位点(第2 388位,第2 752位,第2 766位)和4种基因单倍型,其中抗性基因仅一种单倍型(H1),感病基因有三种单倍型(H2, H3, H4),H2为优势单倍型(84.84%)。本研究结果为开发和利用中日韩地区稻种资源和品种布局提供了依据。     

Identification of two types of differentiation in cultivated rice (Oryza sativa L.) detected by polymorphism of isozymes and hybrid sterility

Magnitudes of genetic variation within each of major varietal groups of cultivated rice were surveyed in terms of isozyme polymorphism and allelic differentiation of hybrid sterility loci, both of which are considered to have litt le selective value. Allelic differences for 20 isozyme loci were examined in a total of 337 accessions, including Indica and Japonica rices. Aus cultivars from India, Javanica cultivars and both landraces and cultivars from China. Eleven out of the 20 isozyme loci were polymorphic. The Aus cultivars contained more alleles per locus than others. The hybrid sterilities in the crosses among Chinese cultivars, Indica and Japonica cultivars were mainly controlled by locus S-5, whereas the hybrid sterilities of Aus cultivars, when they were crossed to Indica, Japonica or Javanica cultivars, were found to be controlled by allelic interaction at hybrid sterility loci S-5, S-7, S-9 and S-15. Also in terms of the number of alleles at S-5 and S-7, Aus cultivars contained more alleles than others. While the Aus group showed an extreme diversity for both hybrid sterility alleles and isozymes, modern cultivars from the south of YangZi River in China were classified into Indica type and those from the north were into Japonica, which were almost the same as those in Japan. On the basis of the measured polymorphism the Indica-Japonica differentiation was explained by founder effects, i.e., through selection and distribution of two original sources each with a unique set of markers. Contrastingly, the continuous and pronounced diversity in the Aus group was attributed to the absence of such a process. The intermediate groups in Yunnan province and Tai-hu Lake region of China are considered to be isolated from such founder effects, retaining an intermediate diversity in terms of isozymes and hybrid sterility genes. Since hybrid sterility hampers the exchange of genes between cultivars of different groups, the understanding of its genetic basis will be important in rice breeding, particularly in hybrid rice breeding. This revised version was published online in July 2006 with corrections to the Cover Date.     

云南水稻品种的亲和性分析

将１０１个云南水稻品种分别与３个籼型和３个粳型测验品种杂交，考察了各组合Ｆ１的小穗育性。同时对各被测品种的６种形态性状的分化按程氏指数法进行调查，分析了云南稻品种亲和性分化与形态性状分化之间的关系。根据测交Ｆ１小穗育性的高低，参照籼粳测验品种之间Ｆ１的育性水平，可将被测品种的亲和性分成灿型、粳型、中间型、广亲和型和特殊亲和性５个类群。各类群所含品种数分别为４７个、２１个、１６个、６个和５个，另有６     

寒地水稻优质稻米抗稻瘟病性鉴定研究

通过人工接种和自然感病两种方法,共鉴定寒地水稻新品种(系)292份(次),鉴定出高抗新品种(系)22份,适合寒地稻区种植的优质、抗病、农艺性状优良的新品种（系）7份,扩大和充实了抗病基因库。     

Competition of Barnyardgrass with Rice Varieties

A field study was conducted to examine the competition of barnyardgrass with various rice varieties and its effect on propanil effectiveness. Six rice varieties, Ispaniki A', Strymonas and Roxani (Japonica type) and Rea, Skybonnet and Blue belle (Indica type), were grown in a silty loam soil, in 1994 and 1995. The varieties had different 1000 seed weights, which varied from 24 to 40 g. The herbicide propanil was applied at the four-leaf stage of barnyardgrass on half the plot area. Japonica type varieties emerged earlier and had lower numbers of barnyardgrass plants compared to Indica varieties. The time of seedling emergence was significantly and negatively correlated with the seed weight and positively with the number of barnyardgrass plants. The delayed establishment of Indica type varieties favoured rapid barnyardgrass growth at the early stages and resulted in lower effectiveness of propanil, compared to Japonica type varieties. Thus, in controlling barnyardgrass in rice fields it is necessary to take into account the variety grown in order to reduce production costs and the pollution risk to the environment.     

贵州水稻区试品种(组合)对水稻稻瘟病的抗性评价

1996—1998、1999—2002年分别采用苗期喷雾接种及穗期注射接种两种鉴定方法对264份水稻区试新品种(组合)进行了抗稻瘟病性人工接种鉴定，共鉴定出抗性材料74份，其中表现高抗的材料9份，表现抗的材料30份，表现中抗的材料34份，分别占总鉴定品种数的3．41％、11．36％和12．88％。     

亚洲栽培稻的核DNA、线粒体DNA和叶绿体DNA籼粳分化的比较研究

本研究对来自１２个国家的７４份亚洲栽培稻进行了核ＤＮＡ,线粒体ＤＮＡ的ＲＦＬＰ分析和叶绿体ＤＮＡ的ＯＲＦ１００的ＰＣＲ分析结果表明参试的７４个栽培稻品种,除ＣＲ１４７的线粒体基因组的类型较为特殊外,其它７３个品种的细胞核基因组,线粒体基因组,叶绿体基因组均可分为籼粳两种类型,可见籼粳分化是栽培稻核ＤＮＡ,ｍｅｔ ＤＮＡ和ｃｐＤＮＡ遗传分化的主流,同一品种３个ＤＮＡ的籼粳属性即有一致的,又有不一致的     

安徽省水稻区试品种稻瘟病和白叶枯病抗性分析

旨在明确2017-2020年安徽省参试水稻品种对稻瘟病和白叶枯病的抗性情况.用人工喷雾接种和自然诱发相结合的方法测得品种对稻瘟病的抗性,用剪叶接菌方法测得品种对白叶枯病的抗性.结果 表明:659个水稻品种中,48.10％表现为中感稻瘟病,其次为中抗、感、高感,表现为抗病的品种仅占1.06％,没有高抗品种.51.59％表...     

福建省水稻主栽品种对稻瘟病的抗性评价

摘 要：采用室内接种和田间自然诱发的方法分别鉴定了福建省18个水稻主栽品种对水稻苗瘟、叶瘟、穗颈瘟的抗病性。结果表明,供试的水稻品种对苗瘟表现为抗病的品种有11个,表现为感病的品种有7个,占供试品种的61.1%和38.9%;对叶瘟表现为抗病的品种有2个,中抗的品种有12个,中感的品种有2个,感病品种有2个,占供试品种的比率分别为11.1%、66.7%、11.1%和11.1%;主栽品种谷优527、佳辐占和特优627对穗颈瘟抗性最强,为抗病品种;金明优100等6个品种为感病品种;汕优63等2个品种为高感品种。另外,地区间气象因子不是造成水稻品种抗病性差异的主要原因,而小气候对稻瘟病发生程度有较大的影响。     

Translation of continuous artificial selection on phenotype into genotype during rice breeding programs

Understanding genetic diversity among local populations is a primary goal of modern crop breeding programs. Here, we demonstrated the genetic relationships of rice varieties in Hokkaido, Japan, one of the northern limits of rice cultivation around the world. Furthermore, artificial selection during rice breeding programs has been characterized using genome sequences. We utilized 8,565 single nucleotide polymorphisms and insertion/deletion markers distributed across the genome in genotype-by-sequencing for genetic diversity analyses. Phylogenetics, genetic population structure, and principal component analysis showed that a total of 110 varieties were classified into four distinct clusters according to different populations geographically and historically. Furthermore, the genome sequences of 19 rice varieties along with historic representations in Hokkaido, nucleotide diversity and F_ST values in each cluster revealed that artificial selection of elite phenotypes focused on chromosomal regions. These results clearly demonstrated the history of the selections on agronomic traits as genome sequences among current rice varieties from Hokkaido.     

品种混植防治寒地稻瘟病流行效果的研究

本试验采用抗稻瘟病性不同的3个品种为材料,研究了品种混植对寒地稻瘟病流行的防治效果以及对产量、品质的影响。结果表明,在寒地早粳稻作区,利用抗病品种跟感病品种混植可以有效抑制叶瘟、穗颈瘟的发生,随着抗病品种比例的提高,发病率明显下降。不同品种组合抑制稻瘟病效果为-11.5%～-63.2%。品种混植后增加了产量,增产幅度1.5%～12.0%,外观品质和食味品质略有提高。