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141.
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143.
针对城镇污水处理厂的设计,结合处理厂的选址、卫生防护距离、工艺选择和冬季出水结冰问题进行分析,并提出解决办法。 相似文献
144.
通过对章古台沙地上10个科16种灌木树种进行的成活率、保存率、树高、地径等指标的调查,结合各树种定性的生长表现,初步筛选出11种灌木。又连续2年对这11种灌木的树高和地径进行调查,进一步筛选出7种灌木,分别是蒙桑(Morus mongolica)、黄柳(Salix gordejevii)、欧李(Cerasus humilis)、小叶锦鸡儿(Caragana microphylia)、树锦鸡儿(Caragana arborescens)、胡枝子(Lespedeza bicolor)、小叶鼠李(Rhamnus parvifolia)。这7种灌木可以在沙地上健康而稳定地生长,没有回枝现象,4年生苗木树高可达1m以上,地径可达1cm以上。 相似文献
145.
马尾松无性系种子园自由授粉子代测定与配合选择 总被引:1,自引:0,他引:1
对都匀马尾松无性系种子园48个半同胞家系9年生测定林的胸径、树高、材积进行了测定分析,结果表明:各家系间树高、胸径、材积差异极显著,具有较高的遗传力。从中选择出9个优良家系,其树高、胸径和材积平均为7.12 m、9.84 cm和0.037 97 m3,遗传增益分别为10.44%、7.73%和20.80%。从优良家系内选择46株优良单株,其树高、胸径、材积分别增加了53.81%,56.65%和150.18%、材积预期增益为55.05%。这些优良单株可作为贵州省营建马尾松高世代种子园的备选材料。 相似文献
146.
Matti Koivula Timo Kuuluvainen Erkki Hallman Jari Kouki Juha Siitonen Sauli Valkonen 《Scandinavian Journal of Forest Research》2014,29(6):579-592
A large-scale and long-term research and development project Forest management inspired by natural disturbance dynamics (DISTDYN) was initiated in Finland in 2009. The aim is to examine how variation in spatial and temporal scales of felling affects forest structure and biota. Harvesting methods applied in this project include selection, gap, partial and clear felling with variable retention. Rehabilitation is also applied as dead wood is intentionally increased while harvesting. The motivation of the project lies in the growing interest in using natural disturbances as an inspiration of forest-ecosystem management and in the recognition that mid- to small-scale disturbances are a characteristic feature of unmanaged Fennoscandian forests. The effects of felling methods are studied at the stand scale. However, a unique aspect of the project is the focus on landscape-scale impacts of different harvesting alternatives by comparing ca. 150-ha landscape units with varying harvesting regimes. Overall, the project aims at creating a long-lasting multidisciplinary research infrastructure. It also addresses core issues of forest-ecosystem management, including ecological, timber-production, economic and socio-cultural performances of alternative harvesting practices. 相似文献
147.
对1块6.5年生的湿加松无性系测定林的生长性状进行了测定和分析,试验表明,开展湿加松无性系选育是可行的、有效的.具体结果如下:(1)控制湿加松生长变异的因素中,遗传因素与非遗传因素的重要性大约各占50%;而对遗传因素的影响强度,主要为家系效应,其次为无性系效应.树高、胸径、材积的家系平均遗传力分别为0.967,0.88... 相似文献
148.
M. S. Radwan M. M. F. Abdalla G. Fischbeck A. A. Metwally D. S. Darwish 《Plant Breeding》1988,100(4):289-298
Six populations of faba bean (Vicia faba L.) were developed through various selection schemes to examine the influence of selection In improving tolerance to Orobanche crenata (Forsk.) in local faba bean stocks. All populations trace their origin to 209 farmers’ seed lots that were collected from Egypt. The entries of each population were grown during the 1982/1983 season in the Orobanche nursery located at Giza in Egypt. Comparison among means of the selected, populations showed that more progress in improving Orobanche tolerance could be achieved from combined selection between and within lots. Between-lots selection was less efficient than single-plant selection. Results, of this study show that considerable progress could be achieved from selection for Orobanche tolerance in local faba bean germplasm. There was sufficient residual genetic variation in the selected populations to expect substantial progress from further selection for most tolerance traits. 相似文献
149.
Summary Four populations of linseed derived from five parents were advanced from the F2 to the F6 generation by SSD and to the F5 by pedigree selection. These populations were used to compare the efficiency of the two methods in order to provide superior genotypes with respect to grain yield and oil content, i.e. oil yield. The results showed minimum differences between pedigree and SSD lines for grain yield, where in only one cross the SSD lines were significantly superior to the pedigree lines. Since pedigree selection was carried out for both, seed yield and oil content, a positive response to selection was expected. However, early selection for yield, a character with low heritability, was not successful. On the contrary, significant differences for oil content were detected between the two groups of lines in three of the four crosses studied. In these cases the pedigree lines were superior to the SSD lines. These results demonstrate that strict selection in early generations for oil content, a character with comparatively high heritability, is feasible and successful in linseed. However, selection for seed yield should be postponed to later inbred generations. Consequently, in breeding for maximum oil yield of linseed a two-step selection procedure is recommended.Abbreviations PS
pedigree selection
- SSD
single seed descent
- TGW
thousand grain weight 相似文献
150.
Summary A series of experiments was performed in order to evaluate the significance of seed germination and seedling growth in osmotic media as screening methods for drought tolerance.Ten spring wheat (Triticum aestivum L. em Thell.) and one durum wheat (Triticum durum
Desf.) were tested under controlled environments, using polyethylene glycol-6000 (PEG) solutions as the moisture stress inducing media.Tolerance in the rate of endosperm utilization, under stress, prior to the onset of germination varied among cultivars.Germination rate or injury to germination at various concentrations of PEG differed significantly among cultivars. Cultivar rating with respect to injury to germination changed with stress levels. Injury to germination did not correlate with endosperm utilization rate in PEG or in water.Germinating seedlings were tolerant to extreme desiccation up to the stage of emergence of the first leaf from the coleoptile.Growth of photosynthesizing seedlings was monitored as they were carried through an increasing concentration gradient of PEG solutions, ranging from –5.9 to –11.3 bars of water potential. Cultivars significantly differed in seedling growth tolerance to increasing levels of water stress. Seedling growth tolerance across cultivars was not correlated with their germination responses under srress.It is concluded that tolerance to water stress in growing seedlings can be screened for by using PEG-containing nutrient solutions. It can not be predicted from germination tests in osmotica.Work was done under a US-Israel Binational Science Foundation (BSF) Grant no. 1654/78.Contribution from Agricultural Research Organization, The Volcani Center, Bet Dagan, Israel, No. 192-E, 1979 series. 相似文献