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41.
对马尾松毛虫对溴氰菊酯和敌百虫等 2种杀虫剂的敏感毒力基线进行了研究。结果表明 :敌百虫和溴氰菊酯对马尾松毛虫的致死中量LD50 分别为 0 2 1 81 μg·g-1和 1 2 4 61× 1 0 -4μg·g-1,其b值分别为 4 8和 4 9。由于b值远大于 1 ,说明供试马尾松毛虫种群对这 2种药剂的异质性小 ,敏感性好 ,测得结果可作为相对敏感毒力基线。表 1参 7 相似文献
42.
林乐玲 《大连水产学院学报》1996,11(2):74-78
作者介绍了《捕捞许可证数据库网络系统》,这是借鉴国内外管理经验提出的,最终实现大连市渔政部门与所属各县区形成一个渔政管理的计算机通讯网络,为进入“全国渔业管理信息系统工程”做基础准备,其目的利用现有渔政设施逐步提高宏观调控能力,循序渐进达到科学化、规范化的管理效果,使渔业生产获取最佳的经济效益和社会效益。 相似文献
43.
对1985年-1999年山东省主要玉米杂种和自交系遗传组成进行了综合分析。山东省的玉米杂交种和亲本自交系的利用趋向集中,其中鲁玉2号、丹玉13号、掖单13号、烟单14号、掖单12号、沈单7号等7个杂交种利用占67.32%,黄早4、M017、107、478、E28、340、8112等7个自交系利用占72.04%。亲本自交系的来源也趋向集中,主要是塘四平头系统、Reid系统,玉米种质基础狭窄。本文对新品种选育和种质创新进行了讨论。 相似文献
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施肥量与氮肥基追比对西农979产量和品质的效应 总被引:9,自引:1,他引:9
为给小麦品种西农979的优质高产栽培提供理论依据,在高、中两种施肥量(高肥:每公顷施纯氮270kg、P2O5 225 kg、K2O 120 kg;中肥:每公顷施纯氮180 kg、P2O5 120 kg、K2O 120 kg)和氮肥7:3、6:4、5:3 :2、10:0四种基追比例(一次追氮在拔节期进行,两次追氮分别在拔节期与孕穗期进行)条件下,研究了施肥量和氮肥基追比例对西农979产量和品质的影响.结果表明,高肥处理产量比中肥处理产量提高9.66%;无论在中肥或高肥条件下,籽粒产量均随氮肥追施比例的增加而提高.施肥量和氮肥基追比例对千粒重的影响较小,对穗粒数的影响居中,对群体穗数的调控作用较大.氮肥基追并施可显著提高成穗率.随施肥量的提高和氮肥追施比例的加大,群体穗数逐渐增加,籽粒蛋白质含量和湿面筋含量也有逐渐提高的趋势,但蛋白质含量增幅小,湿面筋含量增幅大.高施肥量下,氮肥基追比例5:3:2,西农979的籽粒产量、蛋白质含量和湿面筋含量最高,分别达到8 573.5 kg·hm-2、14.97%和32.12%. 相似文献
49.
ZHANG Ya i Xu Ming hui ZENG Ya wen YAO Chun xin CHEN Shan na 《水稻科学》2007,14(3):189-194
There exists a single nucleotide polymorphism, G or T, at the first base of the donor splice site of waxy gene intron 1 in rice. In order to study the relationship between the first base of the donor splice site of waxy gene intron 1 and amylose content in rice, the one-step PCR method was used to determine whether it is G or T in 220 Yunnan indigenous rice varieties from 14 districts, 55 towns/counties of Yunnan Province, and 101 varieties of which were validated by the PCR-Acc I method. According to the G/T polymorphism, 164 rice varieties showed GG-genotype, while the other 56 fell into TT-genotype, accounting for 74.5% and 25.5% of all the test varieties, respectively. When all the rice varieties were divided into indica and japonica subspecies, it was found that 80.5% of indica rice and 67.0% of japonica rice belonged to GG-genotype. The rice varieties with GG-genotype had significantly higher amylose content (18.95% on average) than those with TT-genotype (all below 16%), but 33 rice varieties with GG-genotype still had low amylose content ranging from 3.91% to 15.93%, and most of them came from the Dai minority area in the Southwest of Yunnan Province. However, there was no significant difference in the mean amylose content of the same GG or TT genotypes between indica and japonica rice, suggesting that different genetic backgrounds, indica or japonica, had no effect on amylose content. The coefficient of correlation between the genotype and amylose content was 0.733 (P<0.01). 相似文献
50.
Soil erosion in mountain rangelands in Kyrgyzstan is an emerging problem due to vegetation loss caused by overgrazing. It is further exacerbated by mountain terrain and high precipitation values in Fergana range in the south of Kyrgyzstan. The main objective of this study was to map soil erodibility in the mountainous rangelands of Kyrgyzstan. The results of this effort are expected to contribute to the development of soil erodibility modelling approaches for mountainous areas. In this study, we mapped soil erodibility at two sites, both representing grazing rangelands in the mountains of Kyrgyzstan and having potentially different levels of grazing pressure. We collected a total of 232 soil samples evenly distributed in geographical space and feature space. Then we analyzed the samples in laboratory for grain size distribution and calculated soil erodibility values from these data using the Revised Universal Soil Loss Equation (RUSLE) K-factor formula. After that, we derived different terrain indices and ratios of frequency bands from ASTER GDEM and LANDSAT images to use as auxiliary data because they are among the main soil forming factors and widely used for prediction of various soil properties. Soil erodibility was significantly correlated with channel network base level (geographically extrapolated altitude of water channels), remotely sensed indices of short-wave infrared spectral bands, exposition, and slope degree. We applied multiple regression analysis to predict soil erodibility from spatially explicit terrain and remotely sensed indices. The final soil erodibility model was developed using the spatially explicit predictors and the regression equation and then improved by adding the residuals. The spatial resolution of the model was 30 m, and the estimated mean adjusted coefficient of determination was 0.47. The two sites indicated different estimated and predicted means of soil erodibility values (0.035 and 0.039) with a 0.05 significance level, which is attributed mainly to the considerable difference in elevation. 相似文献