番茄抗番茄斑萎病毒病育种研究进展

番茄斑萎病毒（Tomato spotted wilt virus,TSWV）是危害番茄（Lycopersicon esculentum Mill.）最重要的病原菌之一,在中国及世界范围内已成为限制番茄生产的重要因素。利用自然番茄抗病资源及抗病基因是控制TSWV的有效方法。秘鲁番茄（Lycopersicon peruvianum Mill.）和智利番茄（Lycopersicon chilense Mill.）等野生番茄是目前发现的抗TSWV的主要自然资源。其中,秘鲁番茄中的显性抗病质量基因位点Sw-5在TSWV抗病遗传育种中发挥重要作用。后续开发和培育了多种与Sw-5连锁的分子标记及含有Sw-5的抗病品种。除此之外,病毒RNA介导基因沉默技术在番茄TSWV抗病育种中也逐渐受到重视。由于目前陆续出现了打破Sw-5基因位点的TSWV分离种,因此今后的工作亟须发掘TSWV新的抗病资源和基因。     

奶牛附红细胞体病感染途径(消化系统接种)的研究

12条健康幼犬．经血液学检查确认无附红细胞体感染后．随机分为对照组和消化道接种组，将奶牛附红细胞体阴性菌血和阳性菌血分别经呼吸道接种对照组和消化道接种组各犬，逐日采血，测定其红细胞感染率，并在红细胞感染率最高的时候，测定其生理指标、血液常规指标及血液生化指标。试验结果表明，消化系统接种组接种前后各犬体温、脉搏、呼吸、血红蛋白和一分钟胆红素无明显差异（P〉0．05）；红细胞感染率、红细胞总数、白细胞总数和总胆红素差异显著（P〈0．05），红细胞感染率最高可达30％。对照组没有明显变化。结果证明，消化道可以感染该病，为该病的预防和控制提供了重要的理论依据。     

Shifts in Cropping System and Its Effect on Human Nutrition: Case Study from India

SUMMARY

More than twenty cropping systems are practiced in India. Rice-wheat and rice-rice are the major cropping systems practiced in an estimated 120 districts and 50 districts of the country, respectively. The rice-wheat cropping system (RWCS) of the Indo-Gangetic Plains (IGP) region of South Asia (Bangladesh, India, Nepal, and Pakistan) is the creation of the agricultural green revolution. Higher production of rice and wheat was necessary to meet the calorie needs of an increasing population in this region; as a result, the percent of malnutrition amongst children and adults decreased during the green revolution era. However, in recent years, there has been a reduction in both the rate of malnutrition decline and of the partial and total factor productivity of the RWCS in India. One of the many reasons for the decreased rate of malnutrition decline is micronutrient deficiency. Malnutrition amongst children and adults is a silent emergency in South Asia, including India. This review compares the food consumption habits, nutritional status, and cropping system practiced for different states of India to provide reasons for shifting the rice-wheat cropping system through crop diversification. Diversification of the RWCS will increase the supply of legumes and vegetables, help to diversify the diets consumed, and increase micronutrient intake. This approach is important for a largely vegetarian population of India, and is therefore, considered to be one of several important Food Systems strategy to address the silent emergency of malnutrition in the region.     

农户贷款拖累农村信用社的经营绩效吗?

利用DEA-Tobit两阶段法,基于某省76家农村信用社的面板数据,对农户贷款发放量与农村信用社经营绩效之间的关系进行了研究,结果表明,农户贷款对提高农村信用社经营绩效有正向影响;为进一步探讨农户贷款影响农村信用社经营绩效的路径,又实证分析了农户贷款比例与影响农村信用社经营绩效的成本收入比、不良贷款率、贷款收息率、营业税金及附加和所得税之间的关系,发现农户贷款比例与成本收入比和贷款收息率正相关,与营业税金及附加和所得税负相关,与不良贷款率不相关。基于以上研究结论,提出了改善农户贷款的对策建议。     

宁南半干旱区灌溉农田高效多熟种植模式研究

针对宁南半干旱区一熟有余、两熟不足的气候条件,在灌溉农田开展了以间作套种为主的高效多熟种植模式试验研究.结果表明,采取立体复合种植,能够有效提高农田第一性生产力和土地利用率,增进光、热、水等农业资源的利用效率,增加农业系统能量产出,提高单位面积经济收入.运用灰色关联分析法对5种间作套种模式和2种单作模式的生产效益综合评价结果,各种植模式的综合效益排序依次为: 马铃薯‖玉米＞小麦/玉米＞豌豆/玉米＞胡麻/甜菜＞玉米单作＞豌豆/向日葵＞小麦单作. 此外,还对不同种植模式的合理运用作了讨论.     

比较教学法及其在植物学教学改革中的应用

介绍了比较教学法的概念及几种形式,阐述了比较教学法在植物学教学改革中的应用,并分析了所取得的效果。     

玉米-辣椒套作高产高效种植模式效益分析

对玉米—辣椒套作高产高效种植模式的经济效益进行了分析。结果表明:套作模式下,玉米产量7 200 kg/hm2以上,辣椒产量约2 777 kg/hm2,总收入34 500元/hm2以上,较玉米单作增收21 804元/hm2左右,经济效益提高171%;较辣椒单作增收10 554元/hm2左右,经济效益提高44.0%。玉米—辣椒套作种植,单位土地面积的经济效益明显提高。大区示范结果表明,该项技术可广泛适用于冀东中高肥水农田区,应用前景广阔。     

Cropping sequence and tillage system influences annual crop production and water use in semiarid Montana,USA

Available water is typically the biggest constraint to spring wheat production in the northern Great Plains of the USA. The most common rotation for spring wheat is with summer fallow, which is used to accrue additional soil moisture. Tillage during fallow periods controls weeds, which otherwise would use substantial amounts of water, decreasing the efficiency of fallow. Chemical fallow and zero tillage systems improve soil water conservation, allowing for increased cropping intensity. We conducted a field trial from 1998 through 2003 comparing productivity and water use of crops in nine rotations under two tillage systems, conventional and no-till. All rotations included spring wheat, two rotations included field pea, while lentil, chickpea, yellow mustard, sunflower, and safflower were present in single rotations with wheat. Growing season precipitation was below average most years, resulting in substantial drought stress to crops not following fallow. Preplant soil water, water use, and spring wheat yields were generally greater following summer fallow than wheat recropped after wheat or alternate crops. Water use and yield of wheat following summer fallow was greater than for chickpea or yellow mustard, the only other crops in the trial that followed summer fallow. Field pea performed best of all alternate crops, providing yields comparable to those of recropped spring wheat. Chickpea, lentil, yellow mustard, safflower, and sunflower did not perform well and were not adapted to this region, at least during periods of below average precipitation. Following summer fallow, and despite drought conditions, zero tillage often provided greater amounts of soil water at planting compared to conventional tillage.     

杂交水稻恢复系桂99的选育与应用

恢复系桂 99系采用栽野杂交中间材料为母本 ,以恢复力强 ,并抗稻瘟病多种生理小种的材料为父本进行杂交即优良基因聚合的技术路线选育而成。用其与珍汕 97A配制的组合汕优桂 99,1990～ 1993年累计推广 2 0 93.0 8万亩 ,获得了较好的经济效益和社会效益。