水稻野败型细胞质雄性不育恢复基因Rf3的定位

以珍汕97A/明恢63的F2群体为材料,应用SSR标记对水稻野败型恢复基因Rf3进行定位。该试验从F2分离群体中筛选出119个极端不育单株组成隐性基因定位群体。针对水稻第1染色体短臂Rf3所在染色体的可能区间,应用37个SSR标记检测亲本,从16个多态性标记中挑选出9个检测定位群体。结果表明物理位置连续排列的SSR标记RM10353、RM1195和RM3746各有8个单株与Rf3基因发生了单交换,且重组子数表现为最少,据此可将Rf3定位于这3个标记的两侧标记内。因此最终将Rf3定位在相距679.9 kb的SSR标记RM10338和RM10376之间。     

的定位

 以珍汕97A/明恢63的F2群体为材料,应用SSR标记对水稻野败型恢复基因Rf3进行定位。该试验从F2分离群体中筛选出119个极端不育单株组成隐性基因定位群体。针对水稻第1染色体短臂Rf3所在染色体的可能区间,应用37个SSR标记检测亲本,从16个多态性标记中挑选出9个检测定位群体。结果表明物理位置连续排列的SSR标记RM10353、RM1195和RM3746各有8个单株与Rf3基因发生了单交换,且重组子数表现为最少,据此可将Rf3定位于这3个标记的两侧标记内。因此最终将Rf3定位在相距679.9 kb的SSR标记RM10338和RM10376之间。     

水稻显性早熟基因Ehd的SSR标记定位

以籼稻品种广陆矮4和粳稻品种台中65为亲本构建高世代回交分离群体,选用分布于水稻全基因组的145个SSR标记对亲本及抽穗期早熟基因进行分析.结果表明,114个标记在亲本间具有多态性,多态率78.6%;在BC3F1群体中,检测到10个标记的基因型来源于供体亲本广陆矮4号;在BC3F2定位群体中,早熟植株数与晚熟植株数的分离比例为3:1,早熟植株平均比晚熟植株提早抽穗21 d;通过SSR标记与抽穗期共分离分析将显性早熟基因Ehd界定在分子标记RM271和RM258之间;Ehd与标记RM184和RM271紧密连锁,遗传距离分别为2.6 cM和2.1 cM,此结果为该基因分子标记辅助选择奠定了基础.     

水稻少分蘖高秆突变体的遗传分析和基因定位

研究水稻少分蘖高秆突变体的分子机理,鉴定出新的水稻少分蘖高秆基因。本研究利用γ射线辐射诱变籼稻品种泸恢H103,获得一个少分蘖高秆突变体,命名为ltn1(low-tiller number)。研究了该突变的主要农艺性状与遗传方式,并对突变体基因LTN1进行了分子定位。结果显示突变体的株高,有效穗,结实率,千粒重,单株产量均与野生型存在显著差异。遗传分析表明突变体ltn1受一对隐性基因控制,将突变体和沈农265的F2代中的突变型个体作为定位群体,利用SSR和Indel分子标记将突变体定位在水稻第8染色体标记RM3840和RM23611之间,物理距离为135 kb的区间。在这个区间内有个预测注释基因LOC_Os08g44510。     

水稻褐飞虱抗性基因的初步定位

本文应用229对水稻SSR引物对来自野生稻的褐飞虱抗性基因进行定位,结果表明引物RM589和RM311在作图群体BC2F2中存在多态性.通过作图软件进行基因和分子标记位点的遗传连锁分析,褐飞虱抗性基因与引物RM589和RM311的遗传距离分别是9.8cM和11.9cM,并将其定位在第6染色体和第10染色体上.     

几个香稻保持系香味的遗传研究

对四川省新选育的7个香稻保持系和1个引进改良的香稻品种的香味遗传和等位性进行了分析,同时,利用微卫星DNA标记对D香2 B和泸香90的香味基因进行了初步定位.结果显示,所有香稻品系(品种)与非香稻杂交,F1植株的叶片均无香味,显示出香味由隐性基因控制;从香与香杂交F1植株、回交BC1F1和F2群体分析看,D香1 B、D香2 B、内香2 B、内香4 B、绵香2 B、绵香3 B、宜香1 B的香味受单隐性基因所控制;泸香90的香味可能受一对抑制基因和一对香味基因控制.初步将D香2 B和泸香90的香味基因定位在第八染色体上,D香2 B香味基因位点与SSR引物RM 210相距17.3 cM,与RM 515相距5.7 cM;泸香90的香味基因位点与RM 515相距4.3 cM.RM 515可应用于水稻分子育种实践.     

水稻显性矮秆基因D55的精细定位

为了改良水稻品种的株型,本研究利用来源于普通野生稻的矮秆突变体lb4d与栽培稻品种(系)187R、广恢998杂交产生的F2群体对显性矮秆基因D55进行了精细定位。结果发现,D55基因对水稻株高具有较强的矮化作用,表现为显性矮秆。在日本晴、广恢998、187R等不同的遗传背景条件下,D55基因造成水稻株高降低30%左右;利用水稻SSR标记引物,D55基因首先被定位在水稻第11号染色体上RM5704和RM202之间3.53 cM区域;为了进一步精细定位D55基因,参考水稻品种日本晴的基因组序列,在D55基因附近区域寻找插入缺失序列,在RM5704和RM202之间发展了4个插入缺失标记,利用这4个标记将D55基因精细定位在indel A-7和indelg-15之间的53.1 kb区域。本基因精细定位的结果为D55基因的图位克隆提供了帮助。     

水稻短光敏不育基因(rpms4)的遗传分析及初步定位

为了深入研究水稻短光敏不育基因,以D38S为母本,华占为父本构建了一个F_2分离群体,对短光敏不育基因控制的遗传规律进行分析。利用集团分离分析法(bulked segregant analysis, BSA)筛选多态性SSR标记,并在多态性标记附近增加标记引物筛选,将获得所有多态性SSR标记对含有248个单株的D38S×华占杂交得到F_2群体进行定位分析。D38S×华占的F_1代植株在南昌早季镜检花粉育性表现正常,自然结实率也正常。对248个F_2群体单株进行育性调查,统计短光可育株与短光不育株分离比,发现短光可育株与短光不育株数分离比符合3:1的分离比,因此可以推测D38S的短光敏不育性状遗传模式符合受1对隐性核基因控制模式。该研究利用集团分离分析法(BSA)从均匀覆盖水稻染色体基因组的3 600对SSR中筛选到7对与该不育基因连锁的标记。利用D38S×华占的F_2群体和7对SSR标记,将短光敏不育基因定位于水稻1号染色体,位于标记RM3442与RM6339之间,遗传图距均为1.2 cM,将该短光敏不育新基因命名为rpms4。本研究为进一步精细定位和克隆rpms4提供了科学依据。     

一个水稻落粒性基因SH1的SSR标记定位

以籼稻品种93-11为轮回亲本,与粳稻品种日本晴杂交并回交的高世代分离群体为研究材料,选用104个多态性的SSR标记对水稻的落粒性基因进行定位。结果表明,在BC₄F₂群体中,6个标记的基因型来自于日本晴;在BC₄F₃定位群体中,难落粒植株数与易落粒植株数的分离比例为3:1,落粒性受1对显性基因控制,命名为SH1;分子标记与落粒性共分离分析将SH1定位在SSR标记RM5389和RM1068、RM1387之间,与3个标记的遗传距离分别为0.7cM、5.5cM和13.1cM,此结果为该基因的分子标记辅助选择奠定了基础。     

水稻抗白叶枯病新基因Xα32(t)的鉴定和初步定位

通过多菌系接种鉴定及抗谱分析,并与目前国际上已知抗白叶枯病基因比较,证明在水稻抗源C4064中含有一个新的抗白叶枯病基因,暂命名为Xα32(t).应用分离集团分析法(BSA),借助SSR和EST等分子标记,对该基因进行了分子标记定位.通过对F2分离群体及F3家系单株进行遗传连锁性检测,发现6个位于水稻第11染色体长臂末端的分子标记RM27256、RM27274、RM2064、ZCK24、RM6293和RM5926与Xα32(t)基因连锁.它们与Xα32(t)基因间的遗传距离分别为2.1、1.0、1.0、O.5、1.5和2.6 cM.其中标记RM6293和RM5926位于染色体近端粒一侧,其他4个标记RM27256、RM27274、RM2064和ZCK24位于基因的另一侧.将Xα32(t)定位在水稻第11染色体长臂末端2.0 cM范围内.     

Location of a high-lysine gene and the DDT-resistance gene on barley chromosome 7

Summary The high-lysine gene in Risø mutant 1508 conditions an increased lysine content in the endosperm via a changed protein composition, a decreased seed size, and several other characters of the seed. The designation lys3a, lys3b, and lys3c, is proposed for the allelic high-lysine genes in three Risø mutants, nos 1508, 18, and 19. Linkage studies with translocations locate the lys3 locus in the centromere region of chromosome 7. A linkage study involving the loci lys3 and ddt (resistance to DDT) together with the marker loci fs (fragile stem), s (short rachilla hairs), and r (smooth awn) show that the order of the five loci on chromosome 7 from the long to the short chromosome arm is r, s, fs, lys3, ddt. The distance from locus r to locus ddt is about 100 centimorgans.     

A note on the origin of Kalanchoë x vadensis Boom & Zeilinga (Crassulaceae)

Summary K x vadensis is a hybrid of K. blossfeldiana and K. marmorata obtained after doubling the number of chromosomes.     

Simultaneous Determination of Four Phenolic Acids in Radix Salviae Miltiorrhizae Formula Granules by QAMS

[Objectives]This study aimed to establish a QAMS(quantitative analysis of multi-components by single-marker)method for simultaneous determination of four phenol...     

Avoidance of leaf rust fungi in wild relatives of cultivated cereals

Summary Avoidance of rust fungi that was based on poor appressorium induction was previously found in Hordeum chilense. In the present study 95 accessions of Triticeae were screened for avoidance of Puccinia hordei. The percentage of appressorium formation per germinated spore ranged from 6 to 90%. On none of the 41 accessions of Aegilops, Agropyron, Elymus, Secale, Thinopyrum or Triticum studied was the rate of appressorium formation lower than 25%. Lower rates of appressorium formation were, however, found on accessions of wild barley species Hordeum brachyantherum, H. marinum, H. parodii and H. secalinum. Its implications in cereal breeding are discussed.     

Mechanisms and diversity of resistance to sorghum shoot fly,Atherigona soccata

Sorghum shoot fly, Atherigona soccata, is one of the important pests of postrainy season sorghums. Of the 90 sorghum genotypes evaluated for resistance to this pest, RHRB 12, ICSV 713, 25026, 93046 and 25027, IS 33844‐5, Giddi Maldandi and RVRT 3 exhibited resistance in postrainy season, while ICSB 463, Phule Anuradha, RHRB 19, Parbhani Moti, ICSV 705, PS 35805, IS 5480, 5622, 17726, 18368 and 34722, RVRT 1, ICSR 93031 and Dagidi Solapur showed resistance in rainy season, suggesting season‐specific expression of resistance to A. soccata. ICSB 461, ICSB 463, Phule Yasodha, M 35‐1, ICSV 700, 711, 25010, 25019 and 93089, IS 18662, Phule Vasudha, IS 18551 and 33844‐5 and Barsizoot had fewer deadhearts than plants with eggs across seasons, suggesting antibiosis as one of the resistance mechanism. Five genotypes exhibited resistance with high grain yield across seasons. Correlation, path and stepwise regression analyses indicated that leaf glossiness, seedling vigour, trichome density, oviposition and leaf sheath pigmentation were associated with the expression of resistance/susceptibility to shoot fly, and these can be used as marker traits to select and develop shoot fly‐resistant sorghums.     

Pollen and pollination experiments. III. The viability of apple and pear pollen as affected by irradiation and storage

Summary Apple and pear pollen was irradiated with doses of 0, 50, 100, 250 and 500 krad (gamma rays) and stored at 4°C and 0–10% r.h. From the in-vitro germination percentages an average LD 50 dose of about 220 krad was estimated. For both irradiated and untreated pollen a close and corresponding lineair relationship existed between germination percentage and pollen tube growth.Irradiated pollen was much more sensitive to dry storage conditions than untreated pollen, resulting in less germination and more bursting. Apparently, irradiation caused the pollen cell membrane to lose its flexibility faster than normal. Rehydration of dry-stored, irradiated pollen in water-saturated air restored germination percentages up to their initial levels. The importance of this procedure in germination trials is stressed.     

Reaction of tritordeum to Fusarium culmorum and Septoria nodorum

Summary Hordeum chilense is a wild barley extensively used in wide crosses in the Triticeae. It could be a valuable source of resistance to Fusarium culmorum and Septoria nodorum. Some H. chilense x Triticum spp. amphiploids, named tritordeums, were more resistant than the parental wheat line to these diseases, others were not. Average contents of ergosterol and deoxynivalenol (DON) suggested that resistance to colonization by Fusarium was the highest for Hordeum chilense, followed by tritordeum and wheat in decreasing order. In particular, the H. chilense genotypes H7 and H17 enhanced the wheat resistance to F. culmorum in its tritordeum offsprings. Resistance to S. nodorum in tritordeum was not associated with tall plant height. There is sufficient genetic variation for resistance to F. culmorum and S. nodorum among tritordeum to allow the breeding of lines combining short straw and resistance to both diseases.     

Disease resistance in protected crops and mushrooms

Summary Cultivars of tomatoes, cucumbers, lettuce and peppers have been bred for resistance to one or more pathogens. Some tomato and cucumber cultivars have resistance to a wide range of diseases. Resistance has been transient in many cases and a succession of cultivars with new genes or new combinations of resistance genes has been necessary to maintain control. There has been a number of notable exceptions and these have included durable resistance to such pathogens asFulvia fulva and tomato mosaic virus. With lettuce the resistance situation is complicated by the occurrence of fungicide resistant pathotypes. There are no strains ofAgaricus bisporus purposely bred for disease resistance.In protected flower crops only resistance to Fusarium wilt in carnations has been purposely bred but differences in disease resistance are apparent in cultivars of many ornamental crops. This is particularly so in chrysanthemums where there are cultivars with resistance to many of the major pathogens. Similar situations occur with other flower crops and pot plants. Cultivars of some species have not been systematically investigated for resistance.The need for genetic resistance will increase with the further reduction, in the limits on pesticide use and an increasing public awareness and importance of pesticide pollution.ADAS is an executive agency of the Ministry of Agiculture, Fisheries and Food and the Welsh Office.     

Genetic constitution and diversity in four narrow endemic redwoods from the family Cupressaceae

The genetic constitution and diversity of four relictual redwoods are discussed in this review. These include monotypic genera of the family Cupressaceae: coast redwood (Sequoia sempervirens), giant sequoia (Sequoiadendron giganteum), dawn redwood (Metasequoia glyptostroboides), and alerce (Fitzroya cupressoides). All four species are narrow endemics, share a number of common phenotypic traits, including red wood, and are threatened species. Fossil history suggests that the ancestors of redwoods probably originated during the Cretaceous and Tertiary periods and flourished thereafter for millions of years. Towards the end of the Tertiary period began their decline and struggle for existence that continued during the subsequent geologic upheavals and climate changes, until the survival of the present-day redwoods in the current restricted locations in the world (USA, China, and South America). Although two species, Sequoiadendron and Metasequoia, are diploids (2n = 22), and the other two are polyploids: Fitzroya a tetraploid (2n = 4x = 44), and Sequoia a hexaploid (2n = 6x = 66); they all share the same basic chromosome number x = 11. The genome size in the hexaploid Sequoia is one of the largest (31,500 MB) in the conifers, while the genome sizes of diploid Metasequoia and Sequoiadendron are about one-third (~10,000 MB) of Sequoia. Genetic diversity in the redwoods is lower than most other gymnosperms, except in Sequoia, which seems to rank near the upper quarter of the coniferous forest trees. Genomic research is sparse in the redwoods, and should be pursued for a better understanding of their genome structure, function, and adaptive genetic diversity.     

The induction in vitro of adventitious shoots in Rosa

Summary Adventitious shoots were formed on excised leaves, roots and callus of Rosa persica x xanthina and on excised leaves of R. laevigata and R. wichuraiana on culture media that included BAP and NAA as growth regulators. Shoots formed freely on freshly cultured callus of R. persica x xanthina but their production declined in successive cultures and ceased after twelve weeks. Transplantation to soil was improved by rooting plantlets in cellulose plugs in vitro and transferring plantlets to soil while still in the plugs.