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排序方式: 共有2213条查询结果,搜索用时 15 毫秒
161.
种子园配置设计的计算机处理系统 总被引:2,自引:0,他引:2
借助计算机辅助进行种子园配置设计,根据不规则山地的定植图,模拟出完全随机、完全随机区组、顺序错位、雌雄区组、平衡不完全区组、拉丁方、矩形区组方、约束随机区组、约束更换区组等设计方案,供使用者选择.软件设计为中文菜单式人机对话形式,应用计算机辅助设计(CAD),复盖和编译等优化技术.经过实际运行结果表明,此系统功能较强,适用性及通用性好,运行速度快,比手工配置效率提高几十倍. 相似文献
162.
ZHENG YongqiResearch Institute of Forestry. Chinese Academy of Forestry. Beijing 《中国林业科技(英文版)》2002,(1)
Family outcrossing rates of Pinus caribaea var. caribaea populations that differed in origin and management were estimated by using isozyme markers. The family outcrossing rates were estimated by (1)fixing the probability of pollen gene frequency (p); (2) allowing pollen gene frequency to vary among families. The estimates of family outcrossing rates for all the populations varied widely among families (clones of the seed orchard), ranging from 0.39 to 2.0. The average family outcrossing rates of both methods were greater than the 相似文献
163.
湿地松种子园无性系间开花结实差异分析 总被引:8,自引:1,他引:7
湿地松种子园内无性系间的生长,开花和结实等性状存在着显著差异,无性素水平和单株水平上的性状相关分析结果基本一致,雌花量与结实量,球果长与宽有较密切的相关关系,而无性素的雌花量与雌花量存在负相关关系。 相似文献
164.
He Zhong-hu 《Euphytica》1991,58(2):165-170
Summary Three groups of characters selected using three methods were used to calculate genetic distance among two groups of winter wheat lines using Euclidean distance based on principal components. These wheat lines were then clustered by the unweighted pair-group arithmetic average method. The relationship between genetic distance and standardized potence was seemingly influenced by genetic materials. In order to obtain promising crosses, it is advisable to select parents from intercluster rather than intracluster materials. The results suggested that the repeatability method was better than the conventional and weighting methods for selecting characters for distance analysis. 相似文献
165.
Summary Several independent tests have shown that climate and weather during sexual reproduction influence the adaptive properties of the Picea abies progenies. This phenomenon is expressed in seed orchards established by moving parent trees, propagated as grafts, from north to south, from high to low elevation, or from outdoor to indoor greenhouse conditions. The progenies exhibit delayed flushing in the spring, later growth cessation of leader shoots in the summer, delayed bud-set, higher frequency of lammas shoots and delayed development of frost hardiness in the autumn compared to progenies reproduced in the colder native environment. The altered performance is persistent. We have found no effect on progenies of photoperiod and temperature treatments given to the males during meiosis and pollen production. However, when crosses were made in early spring (March), inside a heated greenhouse (short day, high temperature), the progenies are less frost hardy during cold acclimation than progenies from identical crosses performed in late spring (May; long day high temperature) in the greenhouse. The most hardy offspring were from crosses performed under outdoor conditions in May (long day, low temperature). These results indicate that some stages in reproduction, such as female meiosis, pollen tube growth, syngamy and early embryo development, are sensitive to temperature and/or photoperiod which then alter the phenotypic performance of the offspring. The most likely explanation is the existence of a regulatory mechanism affecting the expression of genes controlling adaptive traits. If this is true, it must have implications for the genetic interpretation of provenance differences in Norway spruce. 相似文献
166.
167.
抗旱保水剂在果园中的应用效应研究 总被引:14,自引:4,他引:14
利用大田试验的方法研究了KD—1型抗旱保水剂在苹果树上的使用效应。结果表明,每棵果树使用抗旱保水剂25~100g,可使土壤含水量平均增加2.01%~2.25%,土壤容重降低0.093g/cm3,大于0.25mm的团粒结构增加10.28%,果树新梢长度和粗度分别增加3.66cm和0.04cm,单果重平均增加23g,差异明显。但使用保水剂对土壤酸碱度和果实含糖量的影响作用不明显。 相似文献
168.
为避免山地果园单轨运输机运行时碰到前方穿越的移动物体或轨道上的静止障碍物,提高运输机工作的安全性和稳定性,研制了山地果园单轨运输机超声波避障系统。该系统由核心微处理器、超声波探头及收发电路、电源模块、无线通信模块和按键等组成。以规则物块、不规则小石块等作为轨道上的障碍物,以树枝、侧枝较多的盆栽柑橘树作为轨道旁的非障碍物,将超声波探头安装在3个不同位置,使运输机工作在慢、中、快3个不同的速度,测试了避障系统的工作性能。试验结果表明,在一定条件下,避障系统能识别轨道上的障碍物和轨道旁的非障碍物。该研究提升了单轨运输机在轨道上无人驾驶运行的安全性和可靠性。 相似文献
169.
平托花生在红壤果园的水土保持作用与综合利用研究 总被引:7,自引:0,他引:7
果园套种平托花生具有良好的水土保持作用,连续4年定位测定表明,套种平托花生的果园发生地表径流38次,径流总量61t/hm2,无泥沙流失;而对照处理发生地表径流178次,径流总量2482 4t/hm2,流失泥沙42 26t/hm2。平托花生还有改善土壤理化性状的作用,果园套种平托花生3年后,0~20cm的土壤容重为0 98g/cm3,土壤空隙度25 73%,土壤含水量22 5%;而对照分别为1 06g/cm3,18 6%,21 5%。套种平托花生3年后土壤pH值从5 12提高到6 25,酸性改善;有机质从15 26g/kg提高为19 30g/kg;全氮从0 79g/kg提高到1 04g/kg;全磷从0 25g/kg提高为0 30g/kg;但全钾从23 23g/kg下降到19 64g/kg。平托花生营养丰富、适口性好。以平托花生喂养肉兔,平均日增重为21 67g,高于饲喂野生杂草(10 73g)。平托花生以扦插繁殖为主,采用10cm×10cm的扦插距离,在山地(有机质5g/kg)30天后覆盖度达到49%,45天达到87%,60天达到91%;而园地(有机质15g/kg)30天就可以达到80%。采用20cm×20cm的扦插距离,山地需75天达到80%的覆盖,园地75天达到89%。 相似文献
170.