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%。     

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.     

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。     

不同生育期水分胁迫对杂交水稻光合及产量性状的影响

对两个籼型杂交水稻B优827和冈优725分别在分蘖期、孕穗期、开花期进行不同水分胁迫处理,研究光合速率、活性氧(ROS)、超氧化物歧化酶(SOD)活性及其同功酶等生理特性和产量变化。结果显示,轻度水分胁迫下,随着胁迫时间的增加,叶片中光合速率下降、活性氧含量上升,SOD活性也相应增加;重度水分胁迫下,随着胁迫时间的增加,光合速率下降迅速,活性氧含量和SOD活性比轻度胁迫上升幅度大,但胁迫第7～9 d SOD酶活性出现降低。不同程度水分胁迫处理收获后其产量大小分别为对照>轻度>重度。对开花期的SOD进行凝胶电泳显示6条同功酶谱带,并随着胁迫程度的增加其亮度明显升高,而且品种间有明显差异。三个时期抗旱能力比较表明,其大小为孕穗期>开花期>分蘖期。B优827在三个时期的轻度、重度水分胁迫下都表现为抗旱能力比冈优725强。     

两系稻制种穗期病害发生较重的原因及防治措施

调查分析稻粒黑粉病、穗颈稻瘟等两系杂交稻制种穗期主要病害的发生原因,提出了清除菌源、轮换制种、健身栽培、对口药剂防治等防治措施。     

水分对旱稻土壤及植株中主要营养元素含量的影响

在防雨棚池栽条件下研究了不同水分处理下土壤矿质元素的释放及旱稻植株对矿质元素的吸收利用特点。结果表明：土壤水分对土壤N、P、K含量及植株养分吸收存在明显影响。随着土壤水分含量的提高,土壤硝态氪含量显著下降,氨态氪含量显著上升;磷素在低水分处理下先升高后基本保持较高水平,而在高水分处理下有一个升降升的变化过程;钾素在65％、100％水分处理下在分蘖中后期显著大于其它水分处理,而在分蘖前期各水分处理都有一个先降后升的变化趋势。在植株对矿质元素的吸收上,100％水分处理下植株体内的全氮含量一直呈下降趋势,65％、75％处理下磷素变化呈“U”型,其余各处理下植株体内的N、P、K含量都呈W型变化。随土壤含水量的增加,旱稻植株对N、P、K的吸收总量均增加。     

杂交水稻不同不育胞质对干旱的响应

选用生产上常用的4个杂交水稻不育胞质WA型、JW型、G型、K型与高配合力水稻保持系G46B转育形成一套同核异质二元系,在PEG模拟干旱胁迫处理下研究不育胞质对水稻抗旱生理的影响.结果表明:不同水稻不育胞质材料在干旱胁迫下各生理活性差异显著,胞质对核基因调控生理抗旱反应也存在明显差异;JW型等不育胞质在10 % PEG干...     

半干旱栽培稻田不同秸秆覆盖材料的产量效应

采用田间观测的方法,分析了不同覆盖材料对半干旱栽培条件下杂交水稻田间茎蘖数、干物质积累和土壤水分的影响,探讨了不同覆盖材料的产量效应。结果表明:(1)在川西北丘陵旱区进行秸秆覆盖有利于增加非灌溉期田间土壤贮水量,提高田间茎蘖数;秸秆腐烂所释放的养分,缓解了稻田磷钾供应相对不足的现状,有效提高了杂交稻的结实率、有效穗数和千粒重;覆盖处理稻田0~0.5 m土层贮水量较不覆盖处理增加2%~13%,田间茎蘖数增加4%~15%,有效穗数增加4%~8%,结实率增加3%~7%,千粒重增加0.6%~1.7%。(2)在灌溉水源没有保证的丘陵旱区,将半干旱栽培与秸秆覆盖相结合,可有效提高杂交水稻产量。冈优725和D优363实收产量平均值在油菜荚壳覆盖、麦草覆盖和麦糠覆盖处理下分别较对照增加10.2%、7.0%和7.7%。     

氮肥施用量和施用方法对超级杂交稻纹枯病发生的影响

 The experiments of resistance of different super hybrid rice (SHR) combinations to sheath blight (ShB) (Rhizoctonia solani Kühn) and effect of nitrogen fertilizer (NF) dosage and fertilization methods on ShB occurrence were conducted in Hangzhou during 2005-2006. The results indicated that the resistance level of different SHR combinations to ShB were significantly different. For the same combination, the severity of ShB depends on the seeding and transplanting period. The disease index showed a positive correlation with the nitrogen dosage, but depended on resistance level of combination. The ShB severity of susceptible combination showed high positive correlation with NF dosage. At the flowering stage, there were no effect of nitrogen fertilization method on the occurrence of ShB, but the fertilization method showed significantly effect at dough stage. The occurrence of ShB was significantly affected by the supply rate of nitrogen at different rice growing stage. When the total NF supply was 165 kg per hectare, the occurrence of ShB with high NF rate (80%) at early stage (as basal and tillering fertilizer) and low rate (20%) at late stage (as panicle fertilizer) was more serious than that of low NF rate (60%) in early and high NF rate (40%) as panicle fertilizer. The result was the reverse of conventional viewpoint about that high NF supply at rice late growing stage might lead to severe occurrence of ShB.     

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.     

溴甲烷和磷化氢熏蒸杂交稻种对米象和干尖线虫的杀灭效果及对水稻发芽率的影响

在10~15 ℃、16~20 ℃、21~30 ℃3个温度范围下,不同剂量的溴甲烷、磷化氢熏蒸出口杂交稻种的试验表明：溴甲烷、磷化氢能有效地杀灭米象,但不能完全杀灭干尖线虫。熏蒸后对杂交稻种的发芽率检测表明磷化氢对杂交稻种表现安全,但16~20 ℃下,40 g/m3溴甲烷及21~30 ℃下,32 g/m3溴甲烷熏蒸处理24 h,杂交稻种子发芽率显著降低。     

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。     

超级稻病虫发生特点及其药剂防治技术

超级稻从孕穗末至齐穗期如遇上连续阴雨天,稻曲病大发生,纹枯病发生较普遍;二化螟、稻飞虱发生量大,危害较重。在超级稻大田生长期,抓住施药适期,选用高效、内吸、广谱、环保型农药,进行3～4次防治,可有效防控病虫危害,达到节本增效、减少农药污染的目的。     

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.     

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。     

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。     

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。     

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。