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971.
养殖船主尺度(m)为L=31.30-40,50,B=5.50-7.00,H=1.30-1.70,T=1.05-1.44;船型系数为α=0.95-0.99,β=0.99-1.00,δ=0.85-0.90。船型与非动力驳船最为接近。养鱼舱面积为90m^2-180m^2,水体交换利用金属网或船壳凿孔。养殖船具有向大尺度,高造价和废旧船舶利用以及简易化,低成本演变的趋势。安装减流阻渣设施和改进网箱设置方法  相似文献   
972.
对20个杉木不同家系的苗木进行磷素营养要求试验,1年生苗木盆栽试验结果表明:杉木不同家系苗木对磷素营养反应敏感,2g磷处理使苗高、地径分别增益3.7%—96.5%、7.4%—61.1%,4g磷处理使苗高、地径分别增益2.1%—83.1%、3.7%—57.9%,杉木苗期需要磷素营养。三明38、三明67、三明48、三明58四个家系生长比较理想,在0g磷处理下,1年生平均苗高13.0—15.99cm,平均地径0.23—0.27cm,这4个家系具有更大的生长潜力,20个家系间对磷素营养要求方面不存在显著的差异。  相似文献   
973.
Corn leaf aphids (Rhopalosiphum maidis Fitch) are found throughout the year on maize in Hawaii and occasionally cause yield loss. Sweet corn inbred Hi38-71 was observed to have high field resistance to aphids and was chosen for this genetic study. An artificial infestation technique was developed using hair-pin clip cages (2.2 cm diameter) which we devised and built. The cages were applied to field-grown plants into which three wingless viviparous adults were placed. Aphid populations were classified on a 1–10 rating scale after about 2 weeks based on digital images of the cages. Mean aphid coverage ratings were 2.97 for the resistant parent and 7.28 for the susceptible parent (representing >200 insects per cage). The F1 hybrids showed similar susceptibility (6.72), showing resistance to be recessive in nature. Six generations of the cross between Hi38-71 and susceptible inbred Hi27 were artificially infested to provide a generation mean analysis of 360 treated plants over two growing seasons. A joint scaling test showed that the fit to a 3-parameter additive-dominance model satisfactorily explained the observed variability with no assumed linkage or epistasis. We conclude that resistance to corn leaf aphid in Hi38-71 is conferred by a single recessive gene labeled aph. These results concur with a previous study under uncontrolled natural infestation in a single environment. The hair-pin clip cage method was most effective in distinguishing resistant and susceptible genotypes under diverse natural growing conditions in Hawaii.  相似文献   
974.
Salinity is a major abiotic stress to barley (Hordum vulgare L.) growth and yield. In the current study, quantitative trait loci (QTL) for yield and physiological components at the late growth stage under salt stress and non-stress environments were determined in barley using a double haploid population derived from a cross between CM72 (salt-tolerant) and Gairdner (salt-sensitive). A total of 30 QTLs for 10 traits, including tiller numbers (TN), plant height, spikes per line (SPL), spikes per plant (SPP), dry weight per plant, grains per plant, grain yield, shoot Na+ (NA) and K+ concentraitions (K) in shoot, and Na+/K+ ratio (NAK), were detected, with 17 and 13 QTLs under non-stress and salt stress, respectively. The phenotypic variation explained by individual QTL ranged from 3.25 to 29.81%. QTL flanked by markers bPb-1278 and bPb-8437 on chromosomes 4H was associated with TN, SPL, and SPP under salt stress. This locus may be useful in the breeding program of marker-assisted selection for improving salt tolerance of barley. However, QTLs associated with NA, K, and NAK differed greatly between non-stress and salt stress environments. It may be suggested that only the QTLs detected under salt stress are really associated with salt tolerance in barley. D. Xue and Y. Huang contributed equally to the article.  相似文献   
975.
黄瓜耐弱光性状的QTL定位   总被引:15,自引:0,他引:15  
应用“欧洲八号×秋棚”为亲本获得的重组自交系群体为材料,以叶面积增长量为鉴定指标,在弱光条件下(光照强度80滋mol·m-2·s-1,光照时数8h白天/16h夜,温度25℃白天/18℃夜)对黄瓜的耐弱光性状进行了研究。发现该RIL群体的双亲在弱光条件下的叶面积增长量存在明显差异。应用该群体构建的具有234个标记位点的连锁图对控制黄瓜耐弱光的数量性状基因(QTL)进行了研究。共定位了5个叶面积增长量的QTL,每个QTL的贡献率在7.3%~20.2%之间。其中1个QTL显示正效加性效应,4个QTL显示负效加性效应。  相似文献   
976.
玉米自交系8个数量性状的配合力分析   总被引:2,自引:0,他引:2       下载免费PDF全文
用 1 9个玉米自交系按不完全双列杂交配成 90个组合 ,对这 90个组合的玉米籽粒产量等 8个数量性状的配合力进行了研究。结果表明 ,P1 组中 1 68、1 64、1 63、1 69和 1 65等自选系的一般配合力高。P2 组中为H3、H8、H6和 H7的一般配合力高。特殊配合力效应达到极显著的是穗长和穗行数。籽粒产量为正效应 ,其穗长也是高特殊配合力效应的为 1 61× H7等 9个组合 ,其穗行数也为高特殊配合力效应的为 1 61× H6等 9个组合。  相似文献   
977.
杨梅属植物共生结瘤固氮研究进展   总被引:2,自引:0,他引:2  
杨梅属35个种中有28个种能与Frankia放线菌共生结瘤固氮。根据有关文献从杨梅属植物共生固氮根瘤及其内生放线菌的形态结构、杨梅属植物根瘤内生放线菌的分类地位、杨梅属植物共生固氮放线菌的生理生化特性、环境条件对杨梅属植物根瘤共生固氮的影响以及分子生物学方法在杨梅属植物根瘤共生固氮放线菌中的应用等方面作了较为详细的阐述。  相似文献   
978.
生菜等高等植物在CELSS系统中湿养栽培装置的研制。红萍和蔬菜光合作用效率对比试验结果表明:在不同生育期,生菜的光合作用效率是不一样的;定植5天后生菜植株的光合效率不如红萍,定植15天后生菜植株的光合效率与红萍相当。在现有的湿养栽培装置上试种2-3种不同蔬菜,初步整合试验过程,尚无发现与红萍之间存在有害的不兼容性。  相似文献   
979.
The spawning grounds of the chub mackerel (Scomber japonicus) and spotted mackerel (Scomber australasicus) in the East China Sea were estimated based on catch statistics of the Japanese large- and medium-type purse seine fishery from 1992 to 2006. Biometric data were obtained from specimens caught by purse seiners in the East China Sea from 1998 to 2006. Gonadosomatic index (GSI) at 50% sexual maturity of chub mackerel and spotted mackerel females was 2.5 and 2.6, respectively. Using this criterion for GSI, chub mackerel larger than 275 mm and spotted mackerel larger than 310 mm in fork length were considered to be mature. Mature chub mackerel was observed in the area of 15–22°C sea surface temperature (SST), and mature spotted mackerel was observed in the area of 17–25°C SST. The spawning period of chub mackerel ranged from February to June, and that of spotted mackerel ranged from February to May in the East China Sea. The spawning grounds were estimated from the distributions of catch per unit effort (CPUE) of spawners and SST. As a result, the spawning ground of chub mackerel was estimated to be in the central and southern part of the East China Sea and the area west of Kyushu in February, March, and April, and in the central part of the East China Sea, the area west of Kyushu and Tsushima Straight in May, and in Tsushima Straight and western part of the Sea of Japan in June. The spawning ground of spotted mackerel was estimated to be in the central and southern part of the East China Sea and southern coastal area of Kyushu in February, March, and April, and the central and southern part of the East China Sea and the area west of Kyushu in May.  相似文献   
980.
利用60Co-r射线对3个小豆品种的干种子加以辐照处理,其剂量分别为0(CK)、100、200、300、400、500、700Gy,研究了不同辐射剂量处理M1、M2代5个农艺性状的诱变参数.结果表明:(1)M1代农艺性状均有不同程度受抑制,其平均数与辐照剂量呈负相关,且M1的变异是多方向的,对剂量的敏感程度也因品种、性状而异;辐照处理致变力(h12)京农2号在400~500Gy剂量处理下综合5个性状为最大,而冀红四号在200Gy剂量处理下综合5个性状为最大.(2)M2代株高、主茎节数、单株荚数的平均数在400Gy处理时均比对照显著增高,从变异系数的大小来看,M2变异范围较大的剂量株高为400~500Gy、单株美数为300~400Gy、荚长为400~700Gy和单荚粒数为300Gy左右.(3)诱导变异遗传力(h22)反映了通过辐射诱变获得的遗传变异方差占总方差的比率,单株荚数在辐射剂量为300~400Gy、株高在400Gy时的h22、GS、RGS较大.  相似文献   
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