杂交稻对稻瘟病和稻白叶枯病的抗性鉴定

对广东省将推广的54份杂交稻组合对稻瘟病和白叶枯病的抗病性进行了鉴定。对稻瘟病的抗病性鉴定表明:抗病组合共49个,占90.7%;其中,高抗(抗性比≥91%)组合30个,占55.6%。对稻白叶枯病的抗病性鉴定表明:没有高抗(HR)和抗(R)的组合,仅有一个杂交稻组合(西胜2175)表现为中抗(mR),仅占1.9%,其余53个组合都表现感病,占98.1%。进一步分析表明:对稻瘟病表现高抗的30个杂交稻组合都不抗白叶枯病,而中抗白叶枯病的杂交稻组合西胜2175对稻瘟病表现为中抗,抗性比为74%。     

Weedy rice represents an emerging threat to transplanted rice production systems in Japan

Weedy rice is a conspecific weed of cultivated rice (Oryza sativa L.) and is a primary weed of direct‐seeded rice production systems worldwide. The shift in the method of establishing rice, that is, from transplanting to direct seeding, is considered the main reason for the emergence of weedy rice in Asia and, more recently, Japan. Japan has increasingly adopted directly seeded rice, even though this practice remains limited. In this study, I confirmed the relationship between weedy red rice emergence and the adoption of direct‐seeded rice in Japan. Twenty‐seven areas from eight prefectures infested with weedy rice were selected to confirm the relationship between the rice planting method and the emergence of weedy rice. Fields that were severely infested with weedy rice were selected as survey fields for this study. I found no relationship between the method of planting rice and weedy rice emergence. Changes to herbicide application, duration of rice production and hand weeding also contribute to the emergence of weedy rice in transplanted rice fields in Japan. The results of this study indicate that weedy rice could become a serious problem in Japan, even in transplanted rice fields.     

丙草胺防治直播稻田杂草稻的技术研究

为了探寻对栽培稻安全的杂草稻防除技术,采用整株测定法研究了丙草胺对杂草稻的毒力及解草啶减轻丙草胺对栽培稻药害的应用技术,并通过田间试验检验了这一技术的安全性。结果表明:丙草胺在450g/hm2时,可显著抑制杂草稻和栽培稻的生长;采用30mg/L解草啶浸种48h,可显著减轻丙草胺对栽培稻的药害,随着丙草胺施药量的增加,解草啶的保护作用逐渐减弱。田间试验结果说明:用30mg/L解草啶浸种栽培稻48h,丙草胺的施药剂量在450~675g/hm2时对栽培稻安全;当丙草胺剂量为900g/hm2时,栽培稻产量显著下降。     

我国南方稻区水稻骨干亲本纹枯病抗性鉴定与分析

运用改进的纹枯病菌接种法,对当前我国南方稻区17个骨干亲本纹枯病抗性进行了田间鉴定,测定和分析了各材料的纹枯病病级(R_D)、相对病斑高度(H_R)及株高(H_P)。通过试验,将17个骨干亲本分为抗病、中等抗病、中等感病和感病4种类型;筛选出了3个抗病亲本(明恢63、蜀恢527、广恢128)和3个中抗亲本(绵恢725、珍汕97B和协青早B);供试亲本的平均RD为4.78,平均HR为0.52;通过分析,发现纹枯病病级(R_D)和相对病斑高度(H_R)呈极显著正相关(y=8.373x+0.435,y=RD;x=H_R)、株高和病级相关不显著。     

杂草稻与栽培稻叶片生长的竞争性研究

杂草稻造成栽培稻产量的损失主要表现为叶片间的相互竞争。争夺空间、争夺光照矛盾突出。杂草稻主茎叶片多于栽培稻,最大叶片长于栽培稻,最大叶片宽于栽培稻,叶片披散,形似杂交稻叶。如果在667 m2旱直播稻田接种2.5 kg粳性杂草稻籽,栽培稻上部全被杂草稻稻叶覆盖,栽培稻植株瘦黄、弱小,茎、蘖逐步退化消亡,造成基本绝产。     

Weedy rice: An expanding problem in direct‐seeded rice in the Philippines

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.     

不同施氮量对寒地水稻稻瘟病的影响

田间试验条件下研究了不同施氮量对水稻品种‘空育131’和‘垦鉴稻6号’稻瘟病发病程度的影响。结果表明, 稻瘟病的发生程度与施氮量有关, ‘空育131’在施氮量为150 kg/hm2时, ‘垦鉴稻6号’在施氮量为150~170 kg/hm2时, 叶瘟、穗颈瘟的发病率和病情指数低且病情发展进程慢。稻瘟病发生程度与水稻品种有关,‘空育131’的叶瘟发病率、病情指数比‘垦鉴稻6号’高, 但‘空育131’的穗颈瘟发病率、病情指数比‘垦鉴稻6号’低。通过掌握‘空育131’和‘垦鉴稻6号’的施氮量, 可有效控制稻瘟病, 提高水稻产量。     

籼型杂交水稻对稻曲病的田间抗性差异

为了解不同水稻品种在田间的抗性差异及其与农艺性状的相互关系,在相同的土壤环境和栽培条件下,利用稻曲病菌诱发接种鉴定,对56个籼型杂交水稻进行田间抗性差异比较,初步探讨了抽穗期和农艺性状与品种田间抗性的关系.结果表明,不同水稻品种对稻曲病田间抗性存在显著差异,病穗率为0.43%～33.04%,病情指数为0.05～16.14;不同抽穗期的品种稻曲病发病率不同,同一抽穗期的品种对稻曲病的抗性亦表现出明显差异;水稻株高与品种抗性之间呈正相关,相关系数为026(P<0.05);水稻分蘖率、有效穗数、剑叶性状等与品种的田间抗性有一定相关性,但差异不显著(P>0.05);水稻株叶形态和叶色与品种田间抗性没有直接相关性.     

水稻抗条纹叶枯病鉴定方法的研究

鉴于国内至今尚无水稻条纹叶枯病品种抗性鉴定标准的现状,本文分别研究了接种时间、接种强度与水稻接种苗龄3因素对抗性鉴定的影响。结果表明水稻条纹叶枯病的适合抗性鉴定方法应为：接种时间48～72 h, 接种强度2～6头/株和水稻接种龄期0.5～1.5叶龄。以本研究结果为基础制定了水稻条纹叶枯病品种抗性鉴定的江苏省地方标准。     

水稻品种抗黑条矮缩病人工接种鉴定方法

为建立科学有效的水稻品种抗黑条矮缩病人工接种鉴定方法,分别研究了病毒在介体体内的循回时间、接种时间、接种强度、水稻接种苗龄4个因素对鉴定效果的影响。结果显示,病毒在介体体内的循回时间为12~15天或21~24天条件下,鉴定效果优于8~11天和16~17天处理;接种48~72 h条件下,鉴定效果优于12~24 h处理;有效接种强度4~20虫/苗条件下,鉴定效果优于1~3虫/苗处理;水稻接种苗龄0.5~2.5叶龄条件下,鉴定效果优于2.5~3.5叶龄处理。由此构建了水稻抗黑条矮缩病人工接种鉴定方法:循回时间为12~15天、接种时间48~72 h、有效接种强度4~20虫/苗和水稻接种苗龄0.5~2.5叶。在此条件下对不同抗性表现的水稻品种进行鉴定,其鉴定结果与重病区田间鉴定没有显著性差异,表明所建立的人工接种鉴定方法能客观地反映水稻品种对黑条矮缩病的抗性水平。     

噁草酮防除直播稻田杂草稻的施用技术

为确立噁草酮防除直播稻田杂草稻的施用技术,通过温室盆栽试验比较了噁草酮在不同土壤水分环境下对栽培稻的安全性及对杂草稻的防效,并在大田中比较了不同直播方式下其对杂草稻的防效及栽培稻产量的影响。结果表明,透气条件下,噁草酮对栽培稻的药害最低,但对杂草稻的防效也较差;饱和水分条件下对杂草稻防效较好,150 g(a.i.)/hm~2时其出苗率和鲜重的抑制率达89.61%和61.87%,超过450 g(a.i.)/hm~2时完全抑制出苗;但药后播种对栽培稻安全性较高,600 g(a.i.)/hm~2下对其出苗率和鲜重的抑制率仅分别为38.06%和39.96%,播后施药的药害较重,最低剂量150 g(a.i.)/hm~2时抑制率已分别达88.77%和45.52%;淹水条件下,虽对杂草稻有100%的防效,但也完全抑制栽培稻出苗。大田施用噁草酮300、450、600 g(a.i.)/hm~2,旱直播和水直播方式下杂草稻株防效分别为26.88%、43.54%、44.45%和84.88%、85.74%、90.92%;鲜重防效分别为11.58%、20.16%、27.33%和30.86%、53.68%、80.15%。旱直播和水直播方式下施用量分别超过450、300 g/hm~2时栽培稻产量显著增加。综合分析,推荐水直播整地后泥水状态施用300 g(a.i.)/hm~2噁草酮,水层落干后播种,保持土壤湿润且土表不出现水渍,栽培稻顺利出苗后及时上水且不淹没苗心为宜。     

水稻品种抗稻瘿蚊与主要农艺性状的关系

对水稻品种抗稻瘿蚊与主要农艺性状关系的研究结果表明,水稻品种抗稻瘿蚊与其分蘖力、始穗期、抽穗期、齐穗期、生育期、株高、有效穗、穗粒数、结实率、千粒重的相关均不显著。水稻品种抗稻瘿蚊与其主要农艺性状并无矛盾,在抗稻瘿蚊育种中可以选育出高产且抗性强的品种。     

浙江省水稻新品种(系)对稻瘟病的抗性研究

用4个稻瘟病菌小种对浙江省280份水稻新品种(系)进行稻瘟病抗性分析,结果表明:浙江省水稻新品种(系)对稻瘟病菌具有较好的抗性,籼稻和粳稻对参试菌株的全抗率分别为21.62%和39.05%,说明粳稻具有较籼稻更广的抗谱;浙江省新品种(系)对ZB13小种具有较高的感病率,籼稻和粳稻的感病率分别为69.37%和52.07%。     

78个水稻不育系对稻粒黑粉病的抗性评价

 水稻稻粒黑粉病主要为害水稻不育系,是限制我国南方杂交水稻制繁种产量和质量的主要病害因素。为挖掘抗稻粒黑粉病的水稻不育系品种,提供具有抗稻粒黑粉病育种价值的水稻不育系材料,本研究于2014-2016年,采用田间接种稻粒黑粉病菌的方法,对四川、湖北、福建的78个水稻不育系品种进行了稻粒黑粉病菌抽穗期抗性评价。连续3年接种稻粒黑粉病菌试验表明,共有4个水稻不育系品种对稻粒黑粉病表现中抗及以上抗性,大部分为感病品种,其中4766A接种稻粒黑粉病菌后未发病,对稻粒黑粉病表现稳定高抗,为我国首次报道的高抗稻粒黑粉病水稻品种。     

河南省沿黄稻区水稻条纹叶枯病发生规律及其防治技术

纹叶枯病的防效可达73.72%～88.40%;使用5%氟虫腈拌种并在移栽前使用10%吡虫啉喷雾的防效为70.48%～76.82%;秧田使用10%吡虫啉和80%敌敌畏混和喷雾的防效为78.85%～82.47%;使用5%氟虫腈喷雾的防效为77.18%～83.88%.     

江苏省水稻区试品种(系)对白叶枯病的抗性分析

通过 1996～2000年213份江苏省水稻区试品种(系)对水稻白叶枯病抗性鉴定 ,抗性较好的品种有94-44、96218、镇稻272、汕优抗63、汕优084、金优63、109、701、7057、9510、9619、5-172、92-133、扬粳7057、泗稻98-3789、新108、镇稻 99、44/157、9522等品种 ,其中 9510、9522等在生产上推广面积较大。试验表明 ,江苏省区试品种 (系 )中常规中籼、杂交籼稻和杂交中粳稻对水稻白叶枯病抗性较差 ,全抗率分别为36.4 %、27.3%和43.3% ,而中粳稻、单季晚粳和杂交晚粳稻对水稻白叶枯病的全抗率为67.2%、71.4%和72.2% ,抗性相对较好。根据白叶枯病菌不同致病型菌株对参试品种致病率的分布情况分析 ,浙173菌株 (致病型Ⅳ)对杂交中籼、常规中粳稻和杂交中粳稻的致病率较高。这种情况和Ⅳ型菌为江苏省白叶枯病主要致病型相一致。     

Toxicity and selective mechanism of imazamox by weedy rice and imidazolinone-resistant rice in China

Weedy rice (Oryza spp.) is a notorious weed in direct-seeding paddy fields. Because it has anatomical and physiological traits similar to those of cultivated rice, no selective herbicide is effective in controlling weedy rice growing among conventional rice cultivars. Imidazolinone (IMI)-resistant rice lines JD372 and JJ818 have been planted with imazamox to control weedy rice in Jiangsu and Shanghai, China. Whole-plant dose–response analysis showed that imazamox exhibited high efficacy against three populations of weedy rice. The ED₉₀ of weedy rice populations FN-5, GY-8, and HY-3 were 46.87, 61.43, and 52.17 g a.i. ha⁻¹, respectively, close to the recommended field dose (50 g a.i. ha⁻¹) of imazamox. Conversely, the ED₁₀ values of JD372 and JJ818 were slightly lower than 50 g a.i. ha⁻¹. These findings indicate that imazamox can control weedy rice production in JD372 and JJ818 fields. The acetolactate synthase (ALS) sensitivity of JD372 in vitro was 1714.89-fold lower to imazamox than was that of FN-5. ALS gene sequencing revealed a Ser653Asn point mutation—a common mutation that confers resistance to IMI herbicides in JD372. In addition, higher ALS expression levels in JD372 were found at 24 and 72 h after imazamox treatment. ALS overexpression might partially compensate for the ALS activity of JD372 that was suppressed by imazamox.     

Gene flow from weedy red rice (Oryza sativa L.) to cultivated rice and fitness of hybrids

BACKGROUND: Gene transfer from weeds to crops could produce weedy individuals that might impact upon the evolutionary dynamics of weedy populations, the persistence of escaped genes in agroecosystems and approaches to weed management and containment of transgenic crops. The present aim was to quantify the gene flowrate from weedy red rice to cultivated rice, and evaluate the morphology, phenology and fecundity of resulting hybrids. Field experiments were conducted at Stuttgart and Rohwer, Arkansas, USA. Twelve red rice accessions and an imazethapyr‐resistant rice (Imi‐R; Clearfield^?) were used. RESULTS: Hybrids between Imi‐R rice × red rice were 138–150 cm tall and flowered 1–5 days later than the rice parent, regardless of the red rice parent. Hybrids produced 20–50% more seed than the rice parent, but had equivalent seed production to the majority of red rice parents. Seeds of all hybrids were red, pubescent and dehisced at maturity. For the majority of hybrids, seed germination was higher than that of the red rice parent. The gene flowrate from red rice to rice was 0.01–0.2% and differed by red rice biotype. The hybrids had higher fecundity and potential competitive ability than the rice parent, and in some cases also the red rice parent. CONCLUSIONS: Red rice plants are vectors of gene flow back to cultivated rice and other weedy populations. The progeny of red rice hybrids from cultivated rice mother plants have higher chances of persistence than those from red rice mother plants. Gene flow mitigation strategies should consider this scenario. Copyright © 2009 Society of Chemical Industry     

改进杂交晚稻育秧方式预防水稻黑条矮缩病

对比试验结果表明,杂交晚稻秧田不施或少施基肥和苗肥,培育青色、青黄色健壮秧苗,适当增加大田插本数,可以显著减少水稻黑条矮缩病发病率,增加产量。在对照区平均丛发病率12.8%,平均单产435.5kg/亩情况下,秧田不施肥,大田每丛插2本苗的丛发病率可控制在1%左右,亩产增加100kg上下。