大豆分子标记研究进展──Ⅰ．大豆的RFLP研究

本文详细介绍了近年来有关大豆ＲＦＬＰ研究的最新进展，对大豆ＲＦＬＰ的研究方法及其在遗传育种中的应用进行了评述。     

大豆分子标记研究进展

本文详细介绍了近年来有关大豆ＲＦＬＰ研究的最新进展，对大豆ＲＦＬＰ的研究方法及其在遗传育种中的应用进行了评述。     

分子标记的发展及其在植物研究中的应用

本文概述了分析标记的研究进展和种类，对ＲＦＬＰ、ＲＡＰＤ、ＡＦＬＰ等各种现有分子标记技术的原理及操作步骤进行了简要介绍，并对其在植物研究领域中的应用及其应用前景作了评述和展望。     

PCR产物的RFLP分析在大豆根瘤菌研究中的应用

采用ＰＣＲ扩增１６—２３ｓｒＲＮＡ基因间序列和限制性片段长度多态性（ＲＦＬＰ）法，分析了２７株属于快生、慢生二个类型的大豆根瘤菌。慢生大豆根瘤菌都产生了一条约１９０４ｐｂ大小的ＤＮＡ产物带。用ＨａｅⅢ、ＭｓｐⅠ和ＣｏｆⅠ限制性酶处理２７株菌株ＰＣＲ扩增产物，除ＤＨ４４４和ＬＬ１６外，其余菌株３种酶处理的结果一致，可以分成９种遗传模式组。９种遗传模式组与菌株的地理起源相关，但与细菌的血清学分组无直接关系。利用大豆根瘤菌１６—２３ｓｒＲＮＡ基因序列间的多态性特性，采用ＰＣＲ—ＲＦＬＰ法分组，比血清学更能反映根瘤菌的遗传进化关系。     

花生AFLP指纹图谱

ＡＦＬＰ是一种以ＰＣＲ为基础的ＤＮＡ指纹图谱技术。利用ＡＦＬＰ技术对从国际半干旱所（Ｉ－ＣＲＩＳＡＴ）引进的９份花生抗旱品种绘制指纹图谱,通过引物Ｅ—ＡＣＡ和与之匹配的ＭＣＡＧ和Ｍ—ＣＡＴ,在３００～６０００ｂｐ的范围内共获得１５７７条ＡＦＬＰ扩增产物,每个品种有主带和次带至少７１条之多,其中１０条为多态性的带纹。     

棉花分子标记研究现状

棉花分子标记研究起步较晚，但发展很快。讫今，其研究方法包括“经典”的ＲＦＬＰ、目前广为采用的ＲＡＰＤ及最新发展的ＡＦＬＰ等技术。减数分裂的原位杂交是棉花分子标记的特色，已形成较为定形的ＩＳＨ或ＦＩＳＨ技术。物种起源与演化是棉花分子标记研究的主要内容，同时在ＲＦＬＰ图谱方面取得明显进展。我国本领域工作仅仅开始，但某些方面有希望赶超世界先进水平。本文就上述状况和问题作了概要介绍和分析。     

分子标记及其在作物遗传育种中的应用

本文介绍了同工酶，ＲＦＬＰ，ＳＳＲ，ＲＡＰＤ，ＡＦＬＰ，ＳＴＳ和ＤＮＡ指纹等７种分子标记的原理及其特点，对它们在植物遗传图谱构建 等研究领域中的应用作一概述和展望 。     

RFLP在大豆种质资源及遗传连锁研究中的应用

本综合论述了ＲＦＬＰ在大豆种质资源及遗传连锁研究中的应用。自８０年代后期ＲＦＬＰＹ以大上，现已明确了栽培大豆ＯＧｌｙｃｉｎｅ ｍａｘ），野生在豆（Ｇ．ｓｏｊａ）和半野生大豆（Ｇ．ｇｒａｃｉｌｉｓ）ＲＦＬＰ的变异性；、大量探针已被制备和筛选出来。利用Ｇ．ｍａｘ×Ｇ．ｍａｘ和Ｇ．ｍａｘ×Ｇ．ｓｏｊａ两类组合已绘制出含约５５０个基因座３０００ｃＭ的ＲＦＬＰ遗传连锁图。一些质量性状基因座和数量性状基因座     

利用RFLP和RAPD标记示踪高粱黑束病,霜霉病和丝黑穗病的抗性基因

利用ＲＦＬＰ和ＲＡＰＤ标记示踪高粱黑束病、霜霉病和丝黑穗病的抗性基因Ｏｈ，Ｂ．Ｊ．Ｇｏｗｄａ等限制性片段长度多态性（ＲＦＬＰ）和随机放大多态ＤＮＡ（ＲＡＰＤ）标记已经用于示踪具有重要农艺性状的基因。一旦ＲＦＬＰ或ＲＡＰＤ有效地用于特殊性状标记，就可根...     

美国大豆孢囊线虫生理小种及大豆品种抗性遗传育种研究进展

大豆孢囊线虫是美国大豆生产中造成损失最大的病害。目前从理论上用四个鉴别寄主把大豆孢囊线虫划分为１６个生理小种，但实际上未发现１１号、１２号和１３号生理小种。通过大规模品种资源筛选，已选出一大批抗源，较好的抗源有Ｐｅｋｉｎｇ、ＰＩ８８７８８和ＰＩ４３７６５４等。大豆品种对孢囊线虫的抗性由少数基因控制，在某些情况下与控制种皮颜色的基因有连锁，分子生物学研究表明，分子标记与大豆的抗性有关，ＲＦＬＰ和ＲＡ     

R5期遮荫对大豆植株体内源激素和酶活性的影响

在Ｒ５期利用人为每天遮荫８小时,连续遮荫１０天,研究了遮荫对生殖生长期大豆叶片蔗糖合成酶（ＳＳ）,蔗糖磷酸合成酶（ＳＰＳ）,谷氨酸合成酶（ＧＳ）活性及叶片和子粒中的四种内源激素含量的影响,结果表明：遮荫明显增加叶片的三种酶活性,提高子粒中ｉＰＡ,ＧＡ和ＡＢＡ的含量,改变叶片中ＧＡ,ｉＰＡ和ＩＡＡ的积累方式。认为酶活性及内源激素的变化是大豆忍耐遮荫不良环境积极生理反应,有助于减少产量和品质损失。     

亚麻优异种质创新利用及发展

亚麻种质创新工作采用外源总体DNA导入,Co60-γ射线处理种子、植株以及利用雄性核不育材料进入转育等方法创造新类型、新材料,提供给育种家,培育出一批优异亚麻新品种,促进了亚麻生产的飞速发展.随着新的生物技术和信息技术的突破,对今后种质创新工作进行展望.     

咸宁苎麻产业形势与发展对策

本文阐述了咸宁苎麻产业经营的现状,发展的有利条件,制约因素和进一步发展苎麻产业的构思,以及实现这一构思采取的几项举措:扩大生产规模;加强优质原料基地及龙头企业的建设;提高品牌档次,促进工业带动农业,集科、工、农、贸为一体,走产业经营的发展道路.     

稻田土壤杂草种子库研究

 对江苏省仪征市连年稻麦两熟轮作稻田土壤杂草种子库中杂草种类进行了考查。结果表明, 有11 科22 种杂草的种子主要分布在0～10 cm 土层内。同时, 阐述了土壤种子库杂草种子的来源, 因水分、湿度、光照等自然因素和耕作、人工除草等人为因素, 杂草种子本身的完熟度等综合因素造成了土壤杂草种子库中杂草种子活力的损失与累积, 以及杂草种子萌发与土层深度、水分等的关系, 初步探明了水旱轮作对稻田土壤杂草种子库的影响, 提出了减少杂草种子库种源的对策。     

水稻植株防御白背飞虱为害的某些生理反应

 以对白背飞虱具有不同抗性水平的水稻品种(组合) 为材料, 研究了水稻在白背飞虱为害后稻株体内的生理变化。结果表明, 稻株受害后, 感虫品种(TN1和汕优63) 光合作用速率和叶绿素含量下降比抗虫品种(N 22) 明显; 感虫品种超氧化物歧化酶(SOD) 活性增加, 过氧化物酶(POD) 和过氧化氢酶(CAT) 活性下降, 而抗虫品种POD 和SOD 均增加, CAT减少;感虫品种除丙氨酸含量下降外, 其他氨基酸含量均上升, 尤其是天门冬氨酸、苏氨酸、缬氨酸及蛋氨酸等含量增加很快, 抗虫品种中天门冬氨酸、缬氨酸等含量增加也很快, 但苏氨酸、蛋氨酸、丙氨酸的含量显著下降。     

Effects of fire and fire intensity on the germination and establishment of Acacia karroo, Acacia nilotica, Acacia luederitzii and Dichrostachys cinerea in the field

Background

The native annual tobacco, Nicotiana attenuata, is found primarily in large ephemeral populations (typically for less than 3 growing seasons) after fires in sagebrush and pinyon-juniper ecosystems and in small persistent populations (for many growing seasons) in isolated washes typically along roadsides throughout the Great Basin Desert of the SW USA. This distribution pattern is due to its unusual germination behavior. Ephemeral populations are produced by the germination of dormant seeds from long-lived seed banks which are stimulated to germinate by a combination of unidentified positive cues found in wood smoke and the removal of inhibitors leached from the unburned litter of the dominant vegetation. Persistent populations may result where these inhibitors do not exist, as in washes or along disturbed roadsides. To determine if this germination behavior has influenced population structure, we conducted an AFLP (244 individuals), ISSR (175 individuals) and ISSR+ AFLP (175 individuals) analysis on plants originating from seed collected from populations growing in 11 wash and burns over 11 years from the SW USA.

Results

Genetic variance as measured by both ISSR and AFLP markers was low among sites and comparatively higher within populations. Cluster analysis of the Utah samples with samples collected from Arizona, California, and Oregon as out-groups also did not reveal patterns. AMOVA analysis of the combined AFLP and ISSR data sets yielded significantly low genetic differentiation among sites (Φct), moderate among populations within sites (Φsc) and higher genetic differentiation within populations (Φst).

Conclusions

We conclude that the seed dormancy of this post-fire annual and its resulting age structure in conjunction with natural selection processes are responsible for significantly low among sites and comparatively high within-population genetic variation observed in this species.     

水稻田表水磷素的动态特征及其潜在环境效应的研究

 通过独立排灌式磷肥大田试验探讨了水稻田表水磷素的动态特征及其潜在的环境效应。研究发现, 施入磷肥增加了田表水磷素水平, 首次水样总磷水平为0.201～ 1.301 mg/kg, 溶解磷水平为0.058～ 0.926 mg/kg; 在等量施磷的条件下, 与单施无机磷肥比较, 有机无机磷配施能显著地提高田表水磷素水平; 在首次采样的一周之内, 两者总磷水平相差达3.85～1.89 倍, 但随着时间的推移, 因施磷结构的不同导致田表水磷素水平的差异逐渐缩小并趋于一致。任一次田间排水都存在诱发附近水域水体富营养化的可能。从减少磷素流失的角度出发, 在施磷灌水后约一周之内或田间耘田时, 田间排水磷素流失潜能增大, 另外, 还要避免在雨水集中的季节施用磷肥。     

Comparative study of microorganisms and sensory attributes of condiments from the fermentation of different seeds

Seeds of African locust bean, melon, castor oil bean and soybean were processed and fermented for 3 days to produce local condiments in the laboratory with a method that simulated the traditional production process. Microorganisms associated with their fermentation and the organoleptic properties of the products were compared.Altogether, seven species of bacteria were involved in the fermentation. These included fiveBacillus spp. and one species each ofPseudomonas andStaphylococcus. Their occurrence vary between the seeds on the different days of fermentation. However,Bacillus spp. were present in all the seeds throughout the fermentation period. The sensory evaluation preference rating for the four products was highest for soybean condiment, followed by that made from locust bean. Melon condiment was the least preferred among the four products. Statistical analysis showed that there were significant differences (P0.05) among the four products for each of the four organoleptic properties evaluated by the judges and also for titratable acidity. Glutamic acid level of soybean condiment was highest (0.31%) among the four products with that of melon being the lowest (0.04%). These results could serve as useful indices for the development of starter culture and optimization of production process in commercializing the production of these local condiments.     

Giant Galápagos tortoises; molecular genetic analyses identify a trans-island hybrid in a repatriation program of an endangered taxon

Background

Giant Galápagos tortoises on the island of Española have been the focus of an intensive captive breeding-repatriation programme for over 35 years that saved the taxon from extinction. However, analysis of 118 samples from released individuals indicated that the bias sex ratio and large variance in reproductive success among the 15 breeders has severely reduced the effective population size (N _e ).

Results

We report here that an analysis of an additional 473 captive-bred tortoises released back to the island reveals an individual (E1465) that exhibits nuclear microsatellite alleles not found in any of the 15 breeders. Statistical analyses incorporating genotypes of 304 field-sampled individuals from all populations on the major islands indicate that E1465 is most probably a hybrid between an Española female tortoise and a male from the island of Pinzón, likely present on Española due to human transport.

Conclusion

Removal of E1465 as well as its father and possible (half-)siblings is warranted to prevent further contamination within this taxon of particular conservation significance. Despite this detected single contamination, it is highly noteworthy to emphasize the success of this repatriation program conducted over nearly 40 years and involving release of over 2000 captive-bred tortoises that now reproduce in situ. The incorporation of molecular genetic analysis of the program is providing guidance that will aid in monitoring the genetic integrity of this ambitious effort to restore a unique linage of a spectacular animal.

     

Beta-carotene content of postharvest orange-fleshed muskmelon fruit: Effect of cultivar,growing location and fruit size

The influence of two growing locations (soil types), six fruit sizes, and two years on the postharvestBeta-carotene content of muskmelon (Cucumis melo L. var. reticulatus Naud.) fruit was studied with two different cultivars. Fully abscised commercial size fruit: 9, 12, 15, 18, 23, and 30 (fruit/0.04 M³ shipping box) had highly variableBeta-carotene contents (5.3 to 33.8 µg/g fresh weight) that varied by size class, soil type and cultivar.Beta-carotene content increased with fruit size up to a maximum, though fruit size continued to increase. Find sandy loam soil produced fruit with lessBeta-carotene content than silty clay loam soil. The cultivar Primo contained higherBeta-carotene content levels than cultivar Cruiser. Mesocarp percent moisture content for both Cruiser and Primo at both locations by fruit size was not significantly correlated (r=0.40) withBeta-carotene content. Indicating fruit cell dilution may not contribute to the differences inBeta-carotene content in different fruit size classes.Beta-carotene content of size class 18 fruit from six cultivars grown on the silty clay loam soil for two consecutive years, showed a year, and year by cultivar effect for some cultivars. Whereas, some cultivars did not differ inBeta-carotene content between the two years. This indicates a potential for controllingBeta-carotene content of muskmelon fruit at a constant, high level by careful selection of production cultivar.Mention of a trademark of propriety does not constitute a guarantee or warranty of the product by the US Department of Agriculture or Texas A&M University and does not imply its approval to the exclusion of other products that also may be suitable.