棉花转基因材料的获得及主要农艺性状变异分析

 利用不同棉花受体材料进行花粉管通道法遗传转化研究。通过卡那霉素鉴定、抗虫性鉴定和PCR分子生物学鉴定,证明已成功将Bt基因转化到泗棉3号、辽棉15、中棉所19、中棉所29母本、中棉所35、中棉所36等棉花材料中。通过对转基因材料后代与非转基因材料的铃重、衣分和纤维品质等差异分析,发现花粉管通道转基因后代材料存在广泛的变异。     

小麦花粉管通道法转基因研究进展

自1983年我国学者创立花粉管通道法以来,在多种农作物中得到应用。本文概述了花粉管通道法的转化原理,重点介绍了小麦花粉管通道法转基因的操作技术和各种影响因素,转基因后代的遗传变异以及小麦花粉管通道法所取得的成果,在此基础上,指出应加强外源DNA导入后对受体DNA的作用机理研究,进一步优化各种转化条件,提高转化效率,使花粉管通道法在转移外源基因上发挥更大的作用。     

Bar基因的玉米花粉管通道法转化

通过花粉管通道法利用抗除草剂基因（bar）转化3个玉米自交系,D0代获得35株GUS阳性植株．其中17株PCR阳性植株,除草剂筛选获得抗性植株13株。研究发现DNA溶液浓度影响转化率,当浓度为100μg／ml时,转化率最高,为2．61％。DNA导入时间距人工授粉时间的延长,结实率升高,但转化率显著下降,人工授粉后1d导入DNA产生的转化株最多,为19株,平均转化率为1．35％。     

花粉管通道转基因技术及在水稻分子育种中的应用

中国学者创立花粉管通道法转基因技术以来,在多种农作物分子育种中得到应用。广泛的研究表明,花粉管通道法转基因技术与其他转基因方法相比,具有能直接得到转化种子,转化频率高,操作简便经济,大量快捷,性状稳定快和导入材料多样性等优点。同时重点介绍了花粉管通道法转基因技术在水稻分子育种中的研究和应用,采用该方法将多种植物外源DNA导入水稻,获得了包括植株形态,产量性状,抗病虫性,稻米品质和生理生化等方面的变异,是一种简便有效的水稻分子育种方法。     

花粉管通道法转化蓖麻的研究

为验证花粉管通道法进行蓖麻转基因研究的可行性，优化花粉管通道法导入方式及导入时间，为花粉管通道法转基因技术在蓖麻分子育种的应用提供参考依据。采用荧光显微观察对蓖麻品种通蓖5号人工授粉后花粉萌发及花粉管生长情况进行了研究，结果表明，花粉管通道法转化蓖麻的最佳时间为授粉后6～24 h。利用花粉管通道技术，将含有GUS基因的植物双元表达载体pPZP221 SGN导入蓖麻品种通蓖5号。对85株T0植株进行PCR检测，得到10株阳性转化植株，阳性率约为11．8％。     

中国转基因抗虫棉国抗12号栽培技术

国抗１２号原代号（ＧＫ－１２）是在国家科技部中国生物工程开发中心和农业部的资助下，由中国农科院生物技术研究中心合成Ｂｔ杀虫基因，并构筑成高效植物表达载休，然后由江苏农科院经作所采用花粉管通道法，导入我国主栽棉花品种泗棉３号中，所获抗虫品系材料经梁山县...     

利用花粉管通道法将外源DNA导入水稻之研究进展

外源DNA直接导入技术以DNA片断杂交假说为理论基础，直接将目的基因或带有目的性状供体遗传物质（总DNA）通过花粉管通道法导入水稻植株，创造大量的变异材料，通过筛选获得目的性状的后代和新品种。由于简单、易行、不受受体植物种类的限制，已被越多的育种者所接受，在水稻的抗病、米质、丰产性上等各方面广为应用。介绍了外源DNA导入方法、外源基因导入类型、后代遗传变异特点及影响花粉管通道法导入的因素，优点、局限性进行了分析，同时提出了问题和展望。     

Bar基因的亚麻花粉管通道法转化

[研究目的]为鉴定T1代转基因亚麻植株中抗除草剂基因(bar)整合是否成功。[方法]通过花粉管通道法将bar基因导入转化植株,以叶片涂抹法对T1代转化植株进行田间草丁膦最低致死浓度筛选;以最低致死浓度草丁膦进行田间喷施后筛选耐受草丁膦药液的抗性植株,并用PCR检测bar基因阳性的抗性植株数目。[结果]草丁膦对T1代转化植株的最低致死浓度为100 mg/L。得到耐受草丁膦药液的抗性植株44株,PCR检测结果表明,8株为PCR阳性植株,平均转化率为18.2%。[结论]花粉管通道法将bar基因成功转入亚麻基因组。     

外源DNA导入花粉管通道技术的发展和应用

本文综述了花粉管通道法的创立与发展,以及应用此方法所取得的一系列研究成果,对遗传转化中所涉及的机理和分子验证进行了探讨,并且分析了影响花粉管通道法导入外源基因的因素,进一步比较了该方法较其它常用的转化法的优势与局限性。     

花粉管通道转基因技术及在小麦分子育种中的应用

文章首先简要回顾了花粉管通道法转基因技术的发展历程,并从花粉管通道法转化的发育及分子证据的提出出发,详细介绍了转化的作用机理和操作技术,提出花粉管通道法转基因技术是一种十分有效的转基因技术,并以变异频率高,性状变异广泛,类型丰富,稳定快,一次导入片段多及低成本等优点而受到科研工作者的亲睐;其次,就花粉管通道转基因技术在小麦分子育种中的应用进行了综述,指出花粉管通道转基因技术在小麦品质创新及分子育种中具有特殊的意义,主要体现在品质改良育种和抗性育种方面,并且取得了可喜的成就,选育出了一系列新品系,如春小麦89122,丰富了品质资源;最后,就花粉管通道法转基因技术存在的问题和应用前景进行了探讨和展望。     

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.     

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.     

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.     

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.     

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.     

Distribution,ecology and reproductive biology of wild tomatoes and related nightshades from the Atacama Desert region of northern Chile

Over the past 20 years, several expeditions were made to northern Chile to collect populations of wild tomatoes (Solanum chilense, S. peruvianum) and allied nightshades (S. lycopersicoides, S. sitiens), and obtain information about their geographic distribution, ecology and reproductive biology. Restricted mainly to drainages of the Andean and the coastal cordillera, populations are geographically fragmented. The two nightshade species are rare and threatened by human activities. Adaptation to extreme aridity and soil salinity are evident in S. chilense and S. sitiens (the latter exhibits several xerophytic traits not seen in the tomatoes) and to low temperatures in S. lycopersicoides and S. chilense. All tested accessions are self-incompatible, with the exception of one S. peruvianum population collected at the southern limit of its distribution. Several distinguishing reproductive traits—anther color, attachment, and dehiscence, pollen size, and flower scent—suggest S. sitiens and S. lycopersicoides attract different pollinators than S. chilense and S. peruvianum. The four Solanum spp. native or endemic to Chile provide a variety of novel traits which, through hybridization and introgression with cultivated tomato, could facilitate development of improved varieties, as well as research on a variety of basic topics, including plant-pollinator interactions, abiotic stress responses, and evolution of reproductive barriers.     

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.     

The exploration of genetic resources of Portuguese cabbage and kale for resistance to several Brassica diseases

Summary Twenty three accessions of nine Portuguese cabbage and kale land races from different geographic origins were tested at the seedling stage for resistance to several important brassica diseases. Resistance to downy mildew (Peronospora parasitica), expressed as necrosis of the cotyledon mesophyll, was found in all the accessions. Type A resistance to cabbage yellows (Fusarium oxysporum f. sp. conglutinans race 1) was present in most of the landraces. Resistance to clubroot (Plasmodiophora brassicae race 6) was found in one accession of the Portuguese tree kale. High resistance to blackleg (Leptosphaeria maculans) and white rust (Albuco candida) was not detected, although several accessions showed 20 to 30% of plants with intermediate expression of resistance. All Portuguese cole accessions were susceptible to blackrot (Xanthomonas campestris pv. campestris).     

Production and characterization of intergeneric diploid cybrids derived from symmetric fusion between Microcitrus papuana Swingle and sour orange (Citrus aurantium)

Plants were regenerated from intergeneric somatic hybridization between embryogenic protoplasts of Microcitrus papuana Swingle and leaf-derived protoplasts of sour orange (Citrus aurantium L.) via electrofusion. The regenerated plants were morphologically similar to the leaf parent in growth vigor, leaf and branch structure. FCM analysis showed that they were diploids. Simple-sequence-repeat (SSR) and cleaved-amplified-polymorphic-sequence(CAPS) were employed for hybridity characterization. SSR banding patterns of the regenerated plants were identical to the leaf parent, sour orange, indicating that they possessed nuclear component derived from sour orange. DNA amplification with chloroplast and mitochondrial universal primers, followed by restriction endonuclease digestion, revealed polymorphism between the fusion parents. Therefore, this method was used to determine the cytoplasmic compositions of the regenerated plants. Banding patterns for all the polymorphic primer/enzyme combinations of the regenerated plants were similar to those of the embryogenic parent, M. papuana, suggesting that only the cytoplasmic components derived from the embryogenic parent were present in the regenerated plants. FCM, SSR and CAPS demonstrated that intergeneric diploid cybrids have been successfully obtained by symmetric fusion. Related results concerning nuclear and cytoplasmic composition of previous diploid somatic hybrids and potential mechanism for regeneration of such kind of plants are discussed herein. This revised version was published online in July 2006 with corrections to the Cover Date.