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941.
水稻单片段替换系群体的建立及QTL定位   总被引:3,自引:0,他引:3  
水稻中许多重要的农艺性状属数量性状,由多基因(QTL)控制。研究QTL的遗传特性和遗传效应对于培育高产和稳产的水稻品种具有十分重要的意义。本研究以6个优良的品种为供体亲本,以华粳籼74为轮回亲本,通过微卫星标记辅助回交选择培育了一批单片段替换系,随后利用所培育的单片段替换系进行了QTL分析和基因定位。主要结果有:1、利用258个微卫星标记对6个供体亲本和轮回亲本间的多态性进行了筛选。6个供体亲本与轮回亲本间的多态率在32.98%至60.78%之间,平均47.81%,粳型供体亲本比籼型供体亲本的多态性要高。2、随着回交代数的增加,植株所含的替换片段数逐渐减少。在BC2F1、BC3F1、BC3F2和BC3F3代,平均每个植株携带有12.50、5.98、1.69和1.46个替换片段。替换片段的平均长度也随回交和自交代数的增加而逐渐变短。在BC2F1、BC3F1、BC3F2和BC3F3代,替换片段的平均长度分别为25.43cM、22.38cM、20.78cM和18.15cM.回交世代替换片段变短的速率(11.99%)比自交世代变短速率(7.15%)要快。在BC2F1、BC3Fl、BC3F2和BC3F3代,轮回亲本基因组的恢复率分别为82.24%、92.55%、98.04%j阳98.52%。3、在BC3F2和BC3F3代,共选育出111个单片段替换系,其中独一无二的单片段替换系共42个。BC3F2代替换系中替换片段的估算长度在2.00cM到64.80cM之间,平均为21.75cM,而BC3F3代中替换片段的估算长度在6.05cM到48.90cM之间,平均为20.95cMc,12条染色体中仅第11染色体没有选择到单片段替换系。所选育的单片段替换系中替换片段的总长为2367.50cM,基因组的覆盖长度为704.50cM,覆盖率为39.25%。4、在52个单片段替换系的22个性状中共鉴定出了234个QTL。每个性状鉴定出的QTL数在3到19个之间,平均4.50个。每个替换系鉴定出的QTL在2到15个之间,平均10.64个。QTL加性效应的大小因性状和替换系不同而不同,低至-0.02(0.79%)的加性效应(如谷粒宽度)均能检测到。在RM237.RM322、RM225和RM481标记附近的各种性状中同时检测到了增效和减效的QTL。5、通过染色体替换作图,对7个单片段替换系中16个性状的QTL进行了定位。利用携带有相同替换片段的替换系进行QTL位置的确定。6、通过分析复杂性状的加性效应,对影响植高、每穗粒数和粒型的相关性状进行了分析,分析QTL之间的相关性。7、对控制抽穗期、稃尖颜色、植株高度和粒型的基因进行了定位。抽穗期基因Hd-8表现为单基因显性遗传,定位于第8染色体上,与PSMl55紧密连锁。紫色稃尖基因Pa-6表现为单基因显性遗传,定位于第6染色体上,与RM253紧密连锁。株高基因Ph-1-3定位于第1染色体上,与PSM331紧密连锁。粒型基因Rlw-8-2为首次报道,定位于第8染色体的末端,与RM447紧密连锁,长粒表现为单基因隐性遗传。本研究通过分子标记辅助选择培育了一批单片段替换系,并成功地对这批材料进行了QTL分析和基因定位,从而证实了在水稻中通过微卫星标记辅助回交选育单片段替换系和进行QTL分析的可行性。  相似文献   
942.
Abstract

The work presents study results on the formation of humus horizons, the accumulation of organic carbon and nitrogen as well as humus composition in successional and reclaimed soils in a sand mine cast in southern Poland. Research plots were designed in chronosequence: 5, 17, 20 and 25 years. Increased thickness of humus horizon and accumulation of organic carbon was reported both in successional soils and in reclaimed soils. However, in corresponding age groups of reclaimed soils these characteristics were two times as high as in successional soils. The estimated accumulation rate of organic carbon (Corg) was three times higher and total nitrogen (Nt) five times higher in reclaimed soils than in successional soils. In both types of soils there was an increase in the amount of carbon trapped with humic and fulvic acid (CHa + CFa) and structure of humic acids. Studies indicated that reclamation treatment significantly accelerated soil-formation in opencast sand mine.  相似文献   
943.
ABSTRACT

Turkey is the fourth leading honey producing country in the world after China, the United States, and Argentina, with around 5.35% of the market. One of the most important problems facing the Turkish beekeeping sector is marketing. In general, the market structure for animal products in Turkey has a confusing chain, which causes great differences between producer and consumer prices. Beekeepers have several alternatives for marketing their honey in Turkey: they may sell directly to consumers (in local markets or roadside stands), to a honey cooperative, to a wholesaler, to a honey packer or dealer, and/or to the export market. This study examines the marketing channels for honey and other bee products in Turkey, discusses the problems and defects of the current system from the perspective of producers and other actors in the market, and suggests solutions that include an increased role for cooperatives and extension services.  相似文献   
944.
This paper reviews our present knowledge of the chromosomal location of the genes that control the synthesis of gliadins and glutenins, the two major groups of storage protein in the endosperm of wheat (Triticum aestivum). Allelic relationships and genetic linkage between genes are also discussed. The areas that require futher investigation are identified.  相似文献   
945.
Among Vaccinium species, blueberries (Vaccinium myrtillus L.) and lingonberries (Vaccinium vitis-idaea) are popular in the human diet. In this study, total phenolic, total flavonoid and total monomeric anthocyanin contents in the ethanol-water extracts of blueberry and lingonberry fruits grown wild in the forests in the central region of Poland were assayed. Antioxidant activities of the extracts from each plant were also evaluated for scavenging ability on 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals and reducing power by cupric reducing antioxidant capacity (CUPRAC) method. Total phenolics in the blueberry extracts ranged from 4.58 to 5.28 mg GAE CE/g fw. The extracts from lingonberry fruits contained higher total contents of phenolic compounds (5.82–7.60 mg GAE/g fw) as well as total flavonoids (5.22–6.47 μmol CE/g fw) than those from blueberries (3.74–4.18 μmol CE/g fw). For the total monomeric anthocyanin contents, the blueberry extracts presented significantly higher values (3.01–3.93 mg cyanidin-3-glucoside (C3G) equivalent/g fw) in comparison to the lingonberry extracts (0.32–0.47). Blueberry extracts exhibited higher antioxidant activity measured by both assays in comparison to lingonberry extracts. Water extracts from fresh and dried fruits also exhibited significant antioxidant activities for both types of berries. Considering the health benefits that have been associated with polyphenolic consumption, these fruits could appear as a good source of this group of phytochemical compounds for their direct consumption or their use as ingredients for the design of new food products or food supplements.  相似文献   
946.
947.
Diets to which testosterone (1 or 10 ng/g diet) had been added were fed to juvenile Atlantic salmon (Salmo salar) for nine months beginning for months after hatching (Experiment 1) and upon completion of yolk absorption (Experiment 2) to determine the effects on growth, gonadal development, and sex ratio. Dietary testosterone at 10 ng/g fed to juvenile salmon at four months after hatching (Exp. 1) induced significant changes in condition factor (0.69±0.01) compared to controls (0.79±0.01) at the end of the test period. In both experiments, salmon treated with 10 ng/g diet induced a significantly higher percentage of male fish compared to controls. Dietary testosterone at 1 ng/g fed to juvenile salmon beginning four months after hatching induced significant increases in weight (18.95±0.99) and length (13.58±0.23) compared to controls (14.55±1.50 and 11.94±0.43, respectively). In Experiment 1 or 2, there was no apparent influence of dietary testosterone on precocious male sexual development. Dietary testosterone at 1 or 10 ng/g fed to juvenile salmon upon completion of yolk absorption (Exp. 2) induced no consistent changes in growth in juvenile Atlantic salmon. These studies indicate that low levels of dietary testosterone may influence physiological responses in juvenile Atlantic salmon dependent upon timing of treatment.  相似文献   
948.
949.
Energy budget calculations, based on published values for changes in biochemical composition and oxygen consumption, have confirmed that metamorphosing bonefish (Albula sp.) larvae from the Gulf of California receive all of their metabolic energy requirements from the breakdown of endogenous reserves. The calculations showed that during metamorphosis, about 80% of the energy was supplied by lipid, and most of the remainder was provided by keratan sulfate glycosaminoglycan. These results support the suggestion that keratan sulfate can function as a storage polysaccharide, a novel function for glycosaminoglycans in vertebrates.  相似文献   
950.
Branchial plasma membranes from the freshwater cichlid teleostOreochromis mossambicus (tilapia) contain two Na+-dependent ATPases: Na+/K+ ATPase, and an amiloride-sensitive ATPase which is postulated to operate as a Na+/H+ (–NH4 +) ATPase. It is suggested that both enzyme activities are located in the basolateral membrane system of the chloride cells. K+ has opposing effects on the two enzymes: it stimulates Na+/K+ ATPase and inhibits Na+/H+ (–NH4 +) ATPase activity. Na+/H+ ATPase appears more sensitive to NH4 + at low concentrations than Na+/K+ ATPase and the stimulatory effect by NH4 + ions on the first enzyme could be important in facilitating NH4 + excretion by tilapia gills under physiological conditions.In vitro maximum stimulation by NH4 + is similar for the two enzymes (200%). In contrast to Na+/K+ ATPase, Na+/H+ ATPase activity is inhibited by supra-physiological (>20 mM) concentrations of NH4 +.  相似文献   
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