杂交水稻制种田稻粒黑粉病的发生与防治

稻粒黑粉病是杂交水稻制种穗期的主要真菌性病害,重病田病粒率高达33.5%,严重影响种子的产量和色泽、发芽率等种子质量。本文对杂交水稻制种田稻粒黑粉病的发病因素、防治措施进行了探讨。     

几种药剂防治水稻制种田穗瘟的药效试验

稻瘟病是鹿寨县水稻主要流行性病害。八十年代以来,随着水稻制种面积逐年扩大和施肥水平的提高,制种田稻瘟病的发生也逐年加重。特别是穗瘟,已成为提高制种田产量的一大障碍。穗瘟病情指数一般为10～20。个别田块高达71.6,减产六成以上。严重地影响水稻制种生产。为了找寻更有效的防治穗瘟病的药剂,根据本地药源情况,我们于1997年在晚稻制种田进行了7种药剂防治穗瘟的药效试验,现将结果报告如下。1　材料与方法1.1　供试药剂及处理　　本试验设置8个处理,即每666.7m2用40%硫环唑胶悬剂200ml(广州金珠江化学有限公司)、40%富士一号乳油100ml(…     

稻粒黑粉病病穗率、病粒率之间的关系测定

稻粒黑粉病(Tilletia horrida)是我县杂交稻制种田的主要病害,其为害率是检验发病程度、防治质量及估计损失率的主要依据。在调查时,往往对病穗率较易调查,但损失率主要按每穗不同病粒数进行测定,工作     

制种田杂交稻粒黑粉病发生与综合防治措施

制种田杂交稻粒黑粉病发生与综合防治措施许长敏（福建省德化县植保检站３６２５００）徐大东（福建省德化县种子公司３６２５００）稻粒黑粉病（ＮｅｓｒｏｓｓｉａｈｏｒｒｉｄａＴａｋ）是我县杂交水稻制种田的主要病害。据调查：夏季制种田母本病穗率高达６０～８０％...     

稻粒黑粉病病穗率与病粒率之间的关系测定

稻粒黑粉病 Neovossia horrida 是我县杂交稻制种田的主要病害,其为害率是检验发病程度、防治质量及估计损失率的主要依据.在调查时,往往对病穗率较易调查,但损失率主要按每穗不同病粒数进行测定,工作量大,且易遗漏,为了提高调查效率,     

江淮杂交制种稻病虫防治研究初报

杂交制种稻主要病虫害种类和发生程度与常规中稻(含杂交稻、下同)有明显区别。发生特点:食叶害虫重于蛀秆害虫,白背飞虱重于褐飞虱、穗病重于叶(鞘)病、不育系病虫害重于恢复系,综合损失很大,重者乃至失收。防治策略:主攻3虫1病(稻蓟马、纵卷叶螟、白背飞虱、粒黑粉病),利用优化制种技术控避病虫害,狠抓苗穗期药剂防治,保叶保粒促高产。     

广西早稻本田病虫草防治

广西早稻病虫草发生严重，常年为偏重程度发生。要做好防治工作，必须贯彻“预防为主、综合防治”的方针，根据水稻的生长特性，做到合理施肥、科学用水、提高水稻抗性，改善田间水气候、减轻病虫发生、在此基础上，认真抓好草害、稻飞虱、穗颈瘟等病虫草的防治。防治的原则是不同的病虫宜采取不同的对策，稻飞虱，三化螟等害虫应采取压前控后；稻纵卷叶螟、纹枯病等病虫的防治以保护三片功能叶不受害为目的，孕穗到抽穗期间为防治重点，穗颈瘟、稻曲病、稻粒黑粉病、三化螟等穗期病虫的防治重点在水稻破口至始穗期间；叶瘟、三化螟等要重点做好病虫中心的防治，以控制其进一步扩散。     

不同药剂防治杂交制种油菜菌核病对比试验

不同药剂防治杂交制种油菜菌核病对比试验武穴市农技推广中心（４３６４Ｏ０）张广油菜菌核病是影响杂交油菜制种产量的重要制约因子之一，这是因为优质杂交油菜华杂ｓ号及其亲本更易感染此病。我们今年在进行华杂３号油菜制种过程中，在防治菌核病的问题上做了大量工作，...     

黑龙江省玉米穗期主要害虫发生概况及防治对策

玉米是黑龙江省第一大粮食作物,穗期害虫对玉米的产量、品质影响最大.介绍了黑龙江省玉米穗期主要害虫亚洲玉米螟、双斑长跗萤叶甲、白星花金龟、玉米蚜的发生情况,并提出了以农业防治为基础,积极开展物理防治、生物防治等绿色技术防控,辅助选用高效、低毒、低残留的化学药剂进行防治的对策与技术措施.     

病虫害专业化统防统治在杂交水稻制种上的应用

通过组建专业化防治组织,在天柱县兰田镇杂交水稻制种工作中开展病虫害专业化统防统治,取得较好的防治效果,提高了杂交水稻的制种效益,具有一定的生态效益和社会效益。     

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     

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%。     

两种氮肥用量对超级稻产量性状和病虫害发生的影响

以6个超级杂交稻组合为材料,初步研究了两种氮肥用量条件下对水稻产量性状和病虫害发生的影响。结果表明,施纯氮360 kg/hm²与施纯氮180 kg/hm²相比,水稻单位面积的有效穗数增加,单株的每穗粒数、结实率和千粒重下降,1 hm²稻田减产6.2%～10.3%。氮肥施用量过高,造成水稻生育后期稻纵卷叶螟、褐飞虱、水稻纹枯病和烟煤病危害加重,尤其是易引起腐生性煤炱菌的滋长。     

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。     

杂交稻自生苗中类似杂草稻的生物学特性

在自然条件下,种植不同时间籼型杂交稻后改种常规粳稻,对粳稻田中的杂交稻自生苗展开调查,分析杂交稻自生苗中出现类似杂草稻的频率及其生物学性状,测定杂交稻自生苗对粳稻产量的影响.结果表明,在粳稻田中籼型杂交稻自生苗可以转变成类似杂草稻,即存在籼粳亚种间异交产生杂草稻的可能;连续种植杂交稻3年后改种常规粳稻田块的杂交稻自生苗密度最高,对常规粳稻产量的影响最大.     

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%。     

Potential gene flow from transgenic rice (Oryza sativa L.) to different weedy rice (Oryza sativa f. spontanea) accessions based on reproductive compatibility

BACKGROUND: The possibility of gene flow from transgenic crops to wild relatives may be affected by reproductive capacity between them. The potential gene flow from two transgenic rice lines containing the bar gene to five accessions of weedy rice (WR1–WR5) was determined through examination of reproductive compatibility under controlled pollination. RESULTS: The pollen grain germination of two transgenic rice lines on the stigma of all weedy rice, rice pollen tube growth down the style and entry into the weedy rice ovary were similar to self‐pollination in weedy rice. However, delayed double fertilisation and embryo abortion in crosses between WR2 and Y0003 were observed. Seed sets between transgenic rice lines and weedy rice varied from 8 to 76%. Although repeated pollination increased seed set significantly, the rank of the seed set between the weedy rice accessions and rice lines was not changed. The germination rates of F₁ hybrids were similar or greater compared with respective females. All F₁ plants expressed glufosinate resistance in the presence of glufosinate selection pressure. CONCLUSIONS: The frequency of gene flow between different weedy rice accessions and transgenic herbicide‐resistant rice may differ owing to different reproductive compatibility. This result suggests that, when wild relatives are selected as experimental materials for assessing the gene flow of transgenic rice, it is necessary to address the compatibility between transgenic rice and wild relatives. Copyright © 2009 Society of Chemical Industry     

Seed morphological traits and genotypic diversity of weedy rice (Oryza sativa f. spontanea) populations found in the Thai Hom Mali rice fields of north-eastern Thailand

Weedy rice ( Oryza sativa f. spontanea ) is a problematic weed in the Thai Hom Mali rice production areas of Thung Kula Ronghai in north-eastern Thailand. There is a great need to initiate studies of weedy rice populations in order to perform basic studies to learn about the seed morphology and genetic diversity. The aims of this study were to determine the seed morphological traits and amylose content and to evaluate the genetic variation, based on the polymorphisms of nuclear and chloroplast DNA, of weedy rice. The seeds and flag leaves were collected from a total of 125 weedy rice plants at six rice fields in the region. For the samples, four morphological traits, the amylose content, and the chloroplast identity (ID) sequence and microsatellite genotypes at the waxy locus were determined. The weedy rice that was collected from the Thung Kula Ronghai region varied considerably in its amylose content and both the seed morphology and genotypes. Some of the weedy rice shared the common microsatellite alleles and chloroplast ID sequence with Thai Hom Mali and wild rice, Oryza rufipogon , indicating that the weedy rice in this region might originate from the introgression between cultivated rice and O. rufipogon , which often takes place in nature, mostly in a one-way process from cultivated rice to O. rufipogon.     

上海地区杂草稻种子越冬能力研究

上海地区杂草稻种子主要分布在0~5 cm土层中,其次为5~10 cm的土层,分别占杂草稻种子库的67.02%和28.87%,不同土层深度中杂草稻种子越冬后的萌发率差异不显著,萌发率在33%~40%。随着土层深度增加,杂草稻种子越冬后出苗率逐渐降低,10 cm以上的杂草稻种子的出苗率均为0,且来源不同的杂草稻存在一定的差异;不同地点采集的杂草稻在室温条件下保存1~12个月均表现出较高的萌发率,但在土壤深埋的条件下,随着埋藏时间的延长不同地点采集的杂草稻萌发率逐渐降低,但是杂草稻萌发率下降速度显著低于水稻。     

Innate factors causing differences in gene flow frequency from transgenic rice to different weedy rice biotypes

BACKGROUND: The compatibility and outcrossing rates between transgenic rice and weedy rice biotypes have been studied in some previous cases. However, few studies have addressed the reasons for these differences. The present study compared the compatibility and outcrossing rates between transgenic rice and selected weedy rice biotypes using manual and natural crossing experiments to elucidate the key innate factors causing the different outcrossing rates. RESULTS: Hybrid seed sets from manual crossing between transgenic rice and weedy rice varied from 31.8 to 82.7%, which correlated directly with genetic compatibility. Moreover, the significant differences in the quantity of germinated donor pollens and pollen tubes entering the weedy rice ovule directly contributed to the different seed sets. The natural outcrossing rates varied from 0 to 6.66‰. The duration of flowering overlap was the key factor influencing natural outcrossing. Plant and panicle height also affected outcrossing success. CONCLUSION: From this study, it is concluded that the likelihood of gene flow between transgenic rice and weedy rice biotypes is primarily determined by floral synchronisation and secondarily influenced by genetic compatibility and some morphological characteristics. Copyright © 2011 Society of Chemical Industry