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During the 1980s, when a flexibleapproach to research, known asfarmer-back-to-farmer, was developed, theInternational Potato Center (CIP) became famousfor participatory research. Subsequently itappeared to have lost leadership in this field.This article documents participatory researchactivities in CIP over the past thirty years tofind out what happened. Even in the 1980s,implementation of participatory research wasactually limited. Participatory research in thecenter grew unevenly, with little clearencouragement from the CGIAR. Decentralizationof social scientists in the 1990s led to thefragmentation of participatory research and, inthe absence of any clear champion, it seemedthat it might wither away. Recently, increasinginterest in IPM, donor support, and therecruitment of international staff who havebeen exposed to other currents of participatoryresearch and training has led to a revival ofinterest. This needs to be carefully nurturedto ensure that the flexibility for whichparticipatory research in CIP earlier gainedworld renown is retained. 相似文献
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育种的成功基于试验材料中具有可利用的遗传变异,了解种质资源的群体机构及遗传变异范围是作物遗传改良的先决条件.本试验通过利用每3 Mb bin均匀分布于水稻染色体的156个SSR标记子,分析了一组(184个)用于干旱适应性研究的水稻种质资源的遗传相似性及群体结构.结果显示,水稻中确实存在着可供利用的遗传多样性,但也存在着普遍的遗传相似性,如国际水稻所的IR品种及菲律宾国家水稻所的PR及BP 水稻品种.通过利用Structure中的混合模型对该184个水稻品种在K=3和K=7时的分析表明,群体结构普遍存在于相同类型或亚种的水稻品种中,籼稻及粳稻品种具有相对明显的群体结构,同一亲本的衍生后代具有显著的遗传相似性和群体结构,不同的群体均存在一定程度的遗传混合.对该组干旱适应性水稻种质资源的遗传相似性及群体结构的研究为今后的抗旱性基因的联合作图,也为合理选择亲本进行水稻抗旱性改良提供了有价值的遗传信息. 相似文献
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试验利用菲律宾旱季无雨的自然干旱条件,大田鉴定了192份水稻种质资源的苗期抗旱性。试验结果表明,水稻种质中存在大量的具有苗期抗旱性的品种。就所观察的三个性状:卷叶(leaf rolling,LeR),枯叶(leaf drying,LeD)及复水恢复(drought recovery rate,DRR)而言,11个水稻品种在卷叶性状(LeR)上,12个水稻品种在枯叶性状(LeD)上极显著优于抗旱性对照品种NSIC Rc 9,14个品种在复水恢复性状(DRR)上显著优于抗旱性对照品种NSIC Re 9。有的品种在两个,甚至3个性状上都比抗性对照显著,表明不同的品种可能采取不同的机制来适应干旱胁迫,如降低叶片面积,及早发深根等:同一抗旱机制也可以作用于不同的表型上,如渗透势调节(Osmoticadiustment)。3个性状间存在极显著的相关,其中LeD与DRR的相关性最高为0.821 62,其次为LeD与LeR为0.801 79和LeR与DRR为0.725 93。对抗旱性性状的选择最好使用田间筛选,因为大田筛选提供了性状表达的真实环境;卷叶,枯叶,和复水恢复能力作为苗期抗旱性指标能有效地筛选苗期抗旱性品种。 相似文献
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Leylani M. Juliano Dindo King M. Donayre Edwin C. Martin Jesusa C. Beltran 《Weed Biology and Management》2020,20(2):27-37
Weedy rice is morphologically similar to cultivated rice (Oryza sativa L.). It has biological characteristics that identify it as a weed. Its important weedy characteristics, that is, early and heavy seed shattering, makes it very difficult to control. Weedy rice has not been reported to be an important weed problem in transplanted, flooded rice. However, the shift to direct‐seeded rice (DSR) due to water issues and high costs of labor has increased reports of weedy rice becoming an expanding important problem in Vietnam, Malaysia, Thailand, and the Philippines. Experts believe that the growing adoption of DSR in Asian countries will result in the rise of weedy rice as one of the top troublesome weeds in rice production. Early and recent surveys in the Philippines have indicated the urgent need to increase awareness of weedy rice among farmers to allow the implementation of a number of effective location‐specific weed management strategies. These surveys and other studies conducted since weedy rice was first reported in 1991 confirmed that weedy rice and grass weed species caused major problems in DSR areas. About 35% of the 4.56 M ha harvested area in the country is planted with DSR. As cultivated and weedy rice are close relatives, it would be very difficult to implement management options very early in crop growth. However, a deeper understanding of the underlying traits of weedy rice can help develop a holistic approach toward effective and economic weed management. 相似文献
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