Seedbed Characteristics and Seeding Depth Effects on Emergence and Seedling Vigour of Upland Rice

Effects of seedbed condition and seeding depth on the emergence and seedling vigour of upland rice was studied. Regardless of aggregate size distribution, seeds sown at 2 cm depth gave the maximum emergence rate (80-90 %) which was reduced to 47 % for sowing at 5 cm depth. Seeding at 10 cm depth caused total failure in emergence. When planted at 2 cm depth, aggregate size produced considerable variation in the speed of emergence but caused no significant differences in final emergence count. For seeds sown at 5 cm depth, seedbed with aggregate size < 2 mm resulted in poor emergence (12 %) while with aggregates > 8 mm reduced emergence by 34 % compared with balanced proportion of larger, moderate and smaller aggregates. Neither the seedbed condition nor seeding depth caused significant variation in seedling height or seedling dry weight.     

珍稀树种的种苗繁殖研究

本文对１０种珍稀树种的采种期、采种方法、种子处理、贮藏方法、育苗方法以及幼苗形态特征等进行了较为系统的介绍。     

光肥在针叶树育苗中的应用研究

为提高针叶树苗木质量，促进针叶树生长，对光肥在针叶树种育苗中的应用进行大量实验研究。结果表明：不同浓度光肥对不同针叶树种苗木苗高、地径生长有促进作用；对种子的萌发亦有一定的影响。光肥适用范围广，应用方法简单，成本低，在针叶树种育苗中可推广应用。     

辽宁春小麦产量结构及增产途径的研究

通过3年小区试验和69块生产田调查,分析了辽宁春小麦产量结构特点和增产途径。产量结构是小麦栽培的中心环节,低、中产田往往由于产量结构不合理,导致产量不高不稳。产量因素间存在明显数量关系,培肥地力,提高田间整齐度,能有效地改善穗粒性状。鉴于辽宁小麦生育期短,分蘖穗小特点,建立高产结构应以主茎成穗为主,增苗抓穗,进而协调产量因素间的关系。     

Prevalence and risk factors in serous arthritis in the carpal joint of Norwegian coldblooded trotters

Of 508 four-year-old coldblooded trotters examined for carpitis, 135 (27%) had the condition. Thirty horses had unilateral carpitis on the left frontlimb, 52 on the right frontlimb and 53 had bilateral carpitis. Of these horses, 105 were stallions, 135 were geldings and 269 were mares. The prevalence of carpitis in these three groups was 25%, 25% and 28%, respectively.Information was obtained on the training regimes in four periods of the life of 378 horses. The odds ratios for the training variables were of the same order in all four periods. In logistic regression analyses on the training variables for the first period for the variable percentage of carpitis within each progeny group (sire index), the odds ratio corresponding to a 10% increase in sire index was 1.7 (1.4, 2.1) (95% confidence interval of the odds ratio). The odds ratios for leaving the horses out in a paddock, walking in a jogcart and fast training, or not in each case, were 0.4 (0.2, 0.9), 2.5 (1.2, 5.3) and 2.0 (0.9, 4.4), respectively. This implies a decreased risk of developing carpitis for horses left out in a paddock as a two-year-old, and a 2.5 and 2.0 times increased risk of carpitis occuring in horses exposed to walking in a jogcart and fast training, respectively.Information on the feeding regimes during the first, second and third year collected by a questionnaire revealed no association with carpitis beyond that which could be ascribed to chance. The rations offered were within normal ranges except for calcium, which was below recommended levels.     

秦川牛保种情况的分析 Ⅰ群体规模、年龄结构与迁移

采用群体遗传学理论与方法研究了陕西省秦川牛场秦川牛保种群30多年来的保种情况,详细地分析了保种群的规模、年龄结构及迁移情况。研究发现,该保种群规模变化剧烈,总的来说规模偏小,尤其是公牛群远小于保种遗传学基本法则规定的最小值;畜群结构不稳定,迁入不规则,该研究结果将为今后采取适当的措施提高保种效果提供科学的参考依据。     

The conserved global regulator VeA is necessary for symptom production and mycotoxin synthesis in maize seedlings by Fusarium verticillioides

The veA or velvet gene is necessary for biosynthesis of mycotoxins and other secondary metabolites in Aspergillus species. In addition, veA has also been demonstrated to be necessary for normal seed colonization in Aspergillus flavus and Aspergillus parasiticus. The present study shows that veA homologues are broadly distributed in fungi, particularly in Ascomycetes. The Fusarium verticillioides veA orthologue, FvVE1, is also required for the synthesis of several secondary metabolites, including fumonisin and fusarins. This study also shows that maize plants grown from seeds inoculated with FvVE1 deletion mutants did not show disease symptoms, while plants grown from seeds inoculated with the F. verticillioides wildtype and complementation strains clearly showed disease symptoms under the same experimental conditions. In this latter case, the presence of lesions coincided with accumulation of fumonisins in the plant tissues, and only these plant tissues had elevated levels of sphingoid bases and their 1-phosphate derivatives, indicating inhibition of ceramide synthase and disruption of sphingolipid metabolism. The results strongly suggest that FvVE1 is necessary for pathogenicity by F. verticillioides against maize seedlings. The conservation of veA homologues among ascomycetes suggests that veA could play a pivotal role in regulating secondary metabolism and associated pathogenicity in other fungi.     

基于粗糙集的迭代阈值选择的玉米苗期背景分割算法研究

将粗糙集与阈值迭代算法相结合,提出了基于粗糙集的迭代阈值选择背景分割算法并将其运用在玉米苗期图像上。利用粗糙集的模糊性刻画目标与背景的边界,用阈值迭代法选取阈值进而实现背景分割。仿真试验结果表明:传统的阈值迭代算法的分割耗时为0.469 s,并且分割后图像存在大量的信息丢失;基于粗糙集的迭代阈值选择背景分割算法的分割耗时为0.374 s,分割图像清晰,能够快速、有效、准确的实现背景分割,并满足农业智能生产中实时性、高效性的要求。     

陕西省八仙镇大力推广烤烟包衣种子育苗技术

2012年八仙镇党委政府拟把种植优质烤烟作为强镇富民产业来抓,得到县烟草部门支持,当年示范推广133.33 hm2,按技术要求,推广烤烟包衣种子育苗技术,经一年来对本区域示范推广技术比较成熟,对该技进行整理。以便今后大面积推广应用。