水稻细胞质雄性不育系裂颖种子的穗上分布规律研究

对4个具有不同裂颖特性的水稻细胞质雄性不育系及其保持系的种子裂颖率和4个不育系种子裂颖粒在穗上的分布特点进行了研究。结果表明：保持系种子裂颖轻于不育系,不育系与相应保持系的种子裂颖率呈显著正相关。不育系种子裂颖与同穗颖花开放的迟早有关,开花迟,裂颖率高;强势穗裂颖轻于弱势穗;一次枝梗轻于二次枝梗;穗上部轻于中部,中部轻于下部;一次枝梗第6粒位裂颖最轻,第2粒位相对较重;强势粒轻于弱势粒。     

杂交水稻种子的裂颖及其危害

杂交水稻种子存在较严重的裂颖现象,这是不育系的一种遗传特性。裂颖种子不耐储藏,随储藏时间的延长,裂颖种子的生活力迅速衰退,发芽率和发芽势降低,秧苗素质差,并严重影响自然混合种子群体的发芽及幼苗生长。选育闭颖能力强的不育系,改进制种技术,强化种子选种,采用多起多落浸种和旱育秧等措施可防治或减轻裂颖种子的危害。     

三系不育系种子裂颖形成的原因及防治措施研究

对扬花期穗部水分与“920”施用量对不育系种子裂颖的影响进行了试验研究．结果表明：赶粉前0．5h起,每隔2h喷水1次对种子裂颖率的提高作用达极显著水平：而赶粉结束后2h喷水1次对种子裂颖率没有显著影响：“920”用量优1A和贺50A以270g／hm^2且抽穗15％时、V20A以315g／hm^2且抽穗10％时喷施为好．随着用量增加裂颖率提高。文章分析了三系不育系种子裂颖形成的原因．并提出了一套解决不育系种子裂颖率高的有效技术措施。     

穗萌抑制剂在杂交水稻制种中的应用

杂交水稻制种中，由于九二○的大量使用，促使种子在母株上过早地突破休眠，加上种子本身颖壳封闭不严，颖壳过薄，裂壳粒多，种子易吸水，从而促使种子在成熟后期收获之前即发芽。据调查，杂交水稻制种一般年份穗发芽率为2％～5％，特殊年份芽谷率可选50％以上。     

影响杂交水稻种子发芽率的因素探讨

对多年不同生态区域生产的不同杂交稻组合的种子发芽率进行了比较分析,认为不育系裂颖特性、制种生态环境和成熟收割期天气条件、制种技术措施、加工及仓贮管理等均能影响杂交稻种子的发芽率。     

如何解决杂交稻种子发芽率偏低问题

生产上杂交水稻种子发芽率较常规稻普遍偏低,这是当前杂交水稻生产中存在的一个不容忽视的问题。稻农对此问题十分敏感,反应强烈,这个问题的解决;对于减少用种量,扩大杂交稻种植面积具有重要现实意义。本文从作物遗传育种与栽培、种子生理、检验与贮藏等角度,就如何解决杂交稻种子发芽率偏低问题提出几点建议,供大家参考。 一、培育选用柱头外露率、颖壳开张角度适当的不育系 为了提高异交结实率,当前生产上制种普遍采用柱头外露率高,颖亮开张角度大的不育系,结果造成柱头内外颖夹持,颖壳闭合不严,柱头夹持率一般在30—40%,裂壳率15%左右,因而杂交稻种子易受外界环境条件的影响,耐贮性明显不如常规稻,如果遇到不良的温湿度条件,则种子易发芽,感病、霉变、遭虫蛀。因此可通过培育选用柱头外露率,颖壳开张角度适当的不育系,既不致于影响制种产量,又可以减低柱头夹持率和裂壳率,来达到提高种子耐藏性的目的。 二、选用不包颈或包颈程在轻的不育系,使用“九二O”增效剂,以减少“丸cO”的用量 当前杂交稻制种中均采用大量施用“九二。”的办法来促进抽穗,提高异交率,由于“九二o”的大量施用,导致种子中*AS诱导a一淀粉酶的产生,使种子中贮藏物质得以消耗分解,从而易诱发微生物、害虫的出现,降低种子播种品质     

扬花期穗部喷水与“九二○”施用对Q2A种子裂颖的影响

对扬花期穗部水分与“九二○”施用量和施用时期对Q2A种子裂颖的影响进行了研究,结果表明：受粉时穗部喷水将极显著提高种子裂颖率;而受粉2 h以后穗部喷水对种子裂颖率没有显著影响;“九二○”施用量以225 g/hm2为好,高于此用量种子裂颖率将随“九二○”用量增加而提高;“九二○”开始施用时期以抽穗25%以后为好,在这之前种子裂颖率随施用时期提前而提高。     

白粒小麦品种(系)穗发芽抗性机制分析

为了解小麦穗发芽抗性机制,应用与抗穗发芽有关的功能标记 Vp1B3、 Vp1b2和 Dorm1并结合整穗发芽、籽粒发芽、籽粒+芒、籽粒+穗轴、籽粒+颖壳和籽粒+芒+穗轴+颖壳共6种发芽试验处理,分析了11个小麦品种（系）的穗发芽抗性机制。结果表明,红粒抗穗发芽对照京9428和京冬8号的抗性受粒色、Vp1Bc、颖壳或颖壳抑制物控制;9个白粒品种(系)穗发芽抗性均不同程度的受芒和颖壳或它们的抑制物控制;强抗穗发芽品系CA0431的抗性与 Vp1B3、 Dorm1和粒色无关,而与其他遗传因素有关;强抗穗发芽品系山东046432属于由Vp1Bc和Dorm1控制的基因型;中抗穗发芽品种矮抗58的抗性与穗轴有关;Vp1Bb基因对CA95502的穗发芽作用有待进一步证实;芒和颖壳或它们的抑制物对白粒中感穗发芽品系CA9640、CA0459、CA0493和白粒高感穗发芽品系山东928802和CA0306的穗发芽均有一定的抑制作用,但 Vp1Bb基因型与山东928802和Vp1Bc基因型与CA0306的穗发芽并无相关。     

"九二○"浓度对水稻不育系制种性状的效应研究

对几个不育系的制种特性及喷施不同浓度“九二○”的制种效果进行了分析,结果表明,不育系的异交结实率、裂颖率、柱头外露率和千粒重等各性状的相关均为不显著水平;喷施不同浓度的“九二○”对各不育系的异交结实率、裂颖率、柱头外露率、包颈粒率和千粒重等特性均产生一定的影响,其中以“九二○”用量10g/666.7m2为宜,各不育系的性状间略有差异。     

裂颖和裂纹对杂交水稻种子发芽和幼苗生长的影响

以3个杂交水稻品种的商品种子为材料,研究了裂颖和裂纹对杂交水稻种子发芽和幼苗生长的影响。结果表明,杂交水稻种子普遍存在裂颖和裂纹现象,种子裂颖率和裂纹率都较高;与非裂颖和非裂纹种子相比,裂颖和裂纹种子发芽势和发芽率降低,幼苗素质较差;裂颖对种子发芽势和发芽率的影响大于裂纹,而糙米裂纹对幼苗生长的影响大于裂颖。     

两份新株型水稻品系的农艺性状与遗传特性分析

[目的]理想株型水稻能提高光合作用效率、经济产量和抗病能力.通过探究两份新株型水稻种质的农艺性状变异和遗传特性,为水稻高产抗病育种提供优异理想株型种质资源.[方法]以两个重组自交系中发现的两份自然重组的新株型种质08yi和RIL60以及由同一自交系选育出来的常规种质08yc和RILc为材料,进行不同生长时期的株型构成因...     

杂交水稻种子特征特性视觉检验分析与图像信息库的建立

为提供机器视觉检验杂交稻种时的检验策略及其各类基本图像信息,将杂交稻种特征特性分为芽谷、重霉、裂颖、点霉、微裂和正常等六类进行检验处理,利用自行研制的数字图像系统采集金优402、汕优10号、中优207、嘉优99、Ⅱ优3207共5个杂交稻种的样品图像,在此基础上运用开发的相关算法软件对每幅图像进行计算,从而获得各类稻种的长、宽、长宽比、面积、紧密度、色调等外观特征参数值范围,进而建立了5个杂交稻种的图像信息库。图像信息库可显示各杂交稻种的典型图像和相关特征值信息,有助于明确其特征特性的分类界限,为检验提供阈值选择的参考,并支持大量图片的管理、新品种的添加等,是机器视觉检验稻种的基础。     

Machine Vision Analysis of Characteristics and Image Information Base Construction for Hybrid Rice Seed

Incompletely closed glumes, germination on panicle and disease are three important factors causing poor seed quality of hybrid rice. To determine how many and which categories should be classified to meet the demand for seed in rice production, the effects of various degrees of incompletely closed glumes, germination on panicle and disease on germination percentage at the harvest and after storage for six months were studied by standard germination percentage test. Six categories of seeds with germ (germinated seeds), severe disease, incompletely closed glumes, spot disease, fine fissure and normal seeds were inspected and then treated separately. Images of the five hybrid rice seed (Jinyou 402, Shanyou 10, Zhongyou 27, Jiayou 99 and 11 you 3207) were acquired with a self-developed machine vision system. Each image could be processed to get the feature values of seed region such as length, width, ratio of length to width, area, solidity and hue. Then all the images of normal seeds were calculated to draw the feature value ranges of each hybrid rice variety. Finally, an image information base that stores typical images and related feature values of each variety was established. This image information base can help us to identify the classification limit of characteristics, and provide the reference of the threshold selection. The management of large numbers of pictures and the addition of new varieties have been supported. The research laid a foundation for extracting image features of hybrid rice seed, which is a key approach to future quality inspection with machine vision.     

高温对光敏水稻与普通水稻结实率降低方式的分析

报道了对农垦５８Ｓ、农垦５８等６个光敏水稻及常规稻进行光周期反应特性分析中,武昌夏季的自然温度对水稻穗发育及结实率的影响。观察到在较高温度下,５ｄ的ＳＤ处理即可使晚粳穗分化启动并抽穗,表明高温对短日诱导穗分化有明显促进作用;同时还观察到在穗分化启动后,温度对幼穗发育进程的光周期效应也有影响,表现为高温可加强长日对幼穗发育的延迟和短日对幼穗发育的促进,而低温则减弱这种作用。在短日照下,对其在不同温度条件下的结实率与温度的相关性分析发现：光敏不育系的结实率均与幼穗发育期的平均温度呈显著负相关,而常规品种的结实率则主要与抽穗扬花期的平均温度呈显著负相关。因此温度在水稻光敏不育中具特殊效应,这种效应与光周期反应基本无关。     

自由空气中CO_2浓度和温度增高对水稻种子活力的影响

大气二氧化碳(CO_2)浓度和气温增高是全球气候变化的重要特征,本研究旨在揭示未来气候变化条件下生长的水稻,其种子活力是否受这两个重要环境因子的影响。利用稻田FACE(Free Air CO_2Enrichment)系统,以常规水稻武运粳23为供试材料,设置对照(Ambient,环境空气)、CO_2浓度增高(比Ambient高200μmol/mol)、温度增高(比Ambient高2℃)和CO_2浓度与温度同时增高四个处理,成熟期收获种子进行实验室标准发芽实验。结果表明,与对照相比,单独CO_2浓度增加使成熟种子浸种24h浸出液电导率平均增加16.5%,但使种子露白率、发芽率、发芽势和发芽指数分别下降7.8%、10.0%、17.4%和8.9%。相似地,单独温度增高或CO_2浓度和温度同时增高处理对上述参数影响的方向一致,但影响的幅度变小,多未达显著水平。与环境生长温度相比,高温环境下全生育期CO_2浓度升高使成熟种子浸种24h浸出液电导率、露白率、发芽率、发芽势和发芽指数的影响变小,表现在CO_2浓度与温度处理间存在一定程度的交互作用。种子发芽后芽和根系性状对高CO_2浓度或高温均无显著响应。以上结果说明,大气CO_2浓度增高200μmol/mol环境条件下,常规粳稻武运粳23成熟种子露白率、发芽率、发芽势和发芽指数等指标均明显下降,但在同时适度增温的生长环境下这种负面影响有减弱的趋势。     

Correlation Between Parents and F1 and Combining Ability of Parents on Seed Dormancy in indica Rice （Oryza sativa）

Dormancy indices of hulled and dehulled seeds were investigated by using 19 cytoplasmic male sterile (CMS) lines, 9 restorer lines and their 109 F1 hybrids of indica hybrid rice. The seeds of each F1 and the parents were harvested on 35 days after flowering. Combining ability was analyzed in 25 combinations made by 5 CMS lines and 5 restorer lines (North Carolina II mating design). The seed dormancy index of F1 was positively and highly significantly correlated with those of their parents and mid-parent value. Out of the 109 combinations, 82 combinations showed mid-parent heterosis, and 43 heterobeltiosis. Seed dormancy indices of F1s and their parents declined dramatically in dehulled seeds compared with hulled seeds, indicating that the hull played an important role in seed dormancy. However, the trends were similar in hulled seeds and dehulled seeds in terms of relationships between the seed dormancy indicices in F1 and their parents. The influence of hull on seed dormancy mainly depended on F1 genotype, not on the hull from maternal parent. The variances of general combining ability (GCA) in female and male parents occupied 59.2% and 31.1% of total variance, respectively. The variance of specific combining ability (SCA) in combinations occupied 9.7% of total variance, indicating that gene additive effects were principal. Among the 5 CMS lines, II112A had the highest GCA effect for seed dormancy, followed by D62A. Among the 5 restorer lines, IR112 had the highest GCA effect for seed dormancy, followed by 2786. These lines are elite parental materials for breeding F1 hybrid rice with stronger seed dormancy.     

Pre-anthesis non-structural carbohydrate reserve in the stem enhances the sink strength of inferior spikelets during grain filling of rice

Sink strength plays an important role in grain filling of cereals but how it is related to the pre-anthesis non-structural carbohydrate (NSC) reserves is not clear. This study investigated if and how an increase in NSC reserves could enhance sink strength, and consequently improve grain filling of later-flowering inferior spikelets (in contrast to the earlier flowering superior spikelets) for rice varieties with large panicles. Two “super” rice varieties (the recently bred high-yielding rice) and two New Plant Type (NPT, named in IRRI for the extra-large panicle) rice lines were compared with two elite inbred varieties under field-grown conditions. Three nitrogen (N) treatments, applied at the stages of panicle initiation, spikelet differentiation or both, were adopted with no N application during the mid-season as control. Both super rice and NPT rice showed a greater yield capacity as a result of a larger panicle than the elite inbred rice. However, a lower percentage of filled grains limited the realization of higher yield potential in super rice and especially in NPT rice, due to their lower grain filling rate and the smaller grain weight of their inferior spikelets. The low grain filling rate and small grain weight of inferior spikelets are mainly attributed to a poor sink strength as a result of small sink size (small number of endosperm cells) and low sink activity, e.g. low activities of sucrose synthase (SuSase) and adenosine diphosphoglucose pyrophosphorylase (AGPase). The amounts of NSC in the stem and NSC per spikelet at the heading time are significantly and positively correlated with sink strength (number of endosperm cells and activities of SuSase and AGPase), grain filling rate, and grain weight of inferior spikelets. Nitrogen application at the spikelet differentiation stage significantly increased, whereas N application at the panicle initiation or at both panicle initiation and spikelet differentiation stages, significantly reduced, NSC per spikelet at the heading time, sink strength, grain filling rate, and grain weight of inferior spikelets in super rice. The results suggest that pre-anthesis NSC reserves in the stem are closely associated with the sink strength during grain filling of rice, and N application at the spikelet differentiation stage would be a good practice to increase pre-anthesis NSC reserves, and consequently to enhance sink strength for rice varieties with large panicles, such as super rice varieties.     

内源IAA对杂交稻强、弱势粒灌浆增重的影响

以超级杂交稻协优9308和杂交稻协优9312、Ⅱ优162及其相应恢复系为材料,对灌浆初期籽粒中内源IAA、糖分的变化,以及IAA抑制剂对IAA以及3H 标记葡萄糖吸收分配和籽粒灌浆的影响进行了研究。结果表明在籽粒灌浆初期强势粒的IAA含量以及增重的速度始终高于弱势粒。在开花受精7 d以前,强势粒中果糖、葡萄糖及蔗糖的含量高于弱势粒,之后相反。强、弱势粒间存在的这种灌浆势差异,杂交组合大于其相应的恢复系。IAA合成及运输抑制剂明显降低3H 葡萄糖在籽粒中的分配。外源IAA对幼穗的处理,缩小了强、弱势粒间结实率的差异,使整穗的结实率也有所提高。