湖南省育成具有水稻淡黄隐性标记性状的不育系

由湖南省怀化职业技术学院承担的湖南省农业厅重点科研项目“水稻标810S淡黄叶突变体的发现与研究”通过了湖南省科技厅组织的科技成果鉴定。由袁隆平院士等组成的专家组考察了试验田现场,认为水稻810S淡黄叶突变体是怀化职院2003年从安农810S繁殖田中发现的一株水稻淡黄叶隐性标记性状的突     

水稻温敏核不育系孕穗期和开花期耐冷性评价

以水稻温敏核不育系安农810 S和奥龙1S为材料,利用自然石灰岩溶洞低温泉水处理,对安农810 S奥龙1S孕穗期和开花期的耐冷性进行了研究.结果表明,无论是孕穗期还是开花期低温处理的奥龙1S,其结实率均高于安农810 S,而结实率下降值和低温敏感指数低于安农810 S,说明奥龙1S的耐冷性强于安农810 S.     

水稻叶色突变体高光合特性研究

标810S是温敏核不育系810S中的淡黄绿叶自然突变株,具有较高的光合速率。本文对突变体的光合色素、光合速率、荧光参数和光合关键酶活性等研究发现,标810S光合色素约为810S的一半,强光条件下标810S光合速率(P_n)比对照高,且没有明显的“午休”现象。标810S气孔导度(Gs)显著增加,叶绿素荧光动力学参数显示,标810S光量子转化效率高;光合酶1,5-二磷酸核酮糖羧化酶(RuBPCase)活性是对照的69.80%,磷酸烯醇式丙酮酸羧化酶(PEPCase)和NADP-苹果酸酶(NADH-ME)却比810S分别上升79.50%和69.06%。研究结果认为,光合色素含量下降是标810S叶片呈淡黄绿叶色的根本原因。突变体通过减少热耗散和提高光合电子传递速率来提高光能利用效率,为暗反应提供足够的同化力,而较高的PEPC活性和较大的气孔导度使其能更有效地固定CO2,光反应和暗反应的协同使突变体具有较高的光合速率。     

广西首个紫红叶标记性状水稻两系不育系育成

近日,广西农作物品种审定委员会办公室组织专家,对贺州市农业科学研究所和广西绿田种业有限公司育成的具有紫红叶标记性状水稻两系不育系紫红10S进行鉴定,认为紫红10S符合国家规定的两系杂交水稻不育系指标,可以在生产上应用。     

水稻叶色突变体xws的基因定位与育种利用

在育种实践中,叶色基因可作为标记性状,对提高杂交制种效率和降低杂交种子生产成本具有重要意义。xws是在水稻两用核不育系的大面积制种田中发现的一株自然黄叶突变体,本研究比较了xws与野生型的主要农艺性状,并对该突变体进行了遗传分析、基因定位及育种利用。结果表明:xws比野生型始穗期推迟3 d,株高、穗长、单株有效穗数、穗粒数均比野生型有所增加,而千粒重比野生型略有减少。遗传分析表明xws黄叶性状受单隐性核基因控制,暂时将其命名为XWS。以xws与R华占杂交的F2群体作为定位群体,将XWS基因定位在水稻第3号染色体分子标记WY152到WY244之间,其遗传距离分别为0.2 cM和0.5 cM。此外,通过xws开展相应的育种利用研究,已选育出稳定的带叶色标记性状两系不育系黄13S,其所配组合展示出极大的应用潜力。     

光敏、温敏核不育水稻核不育基因等位性及基因对数的研究

以光敏核不育系农垦58S及其衍生的光敏核不育系7001S、温敏核不育系W6154S、增矮64S，以及温敏核不育系安农S－1及其衍生的温敏核不育系810S、安湘S、香125S为材料进行相互杂交，在长日高温条件下观察F1的育性，根据其可育性和不育性确定核不育基因的等位性。结果表明：7001S、W6154S、培矮64S与核不育基因供体农垦58S之间有等位点的核不育基因；但温敏核不育系W6154S与培矮64S之间，不具等位点的温敏核不育基因。该结果说明光敏核不育系农垦58S至少存在一对光敏核不育基因和两对温敏核不育基因，而且各对温敏核不育基因可独立遗传，在夏季高温条件下其不育性得到充分表达。安农S－1与其衍生的不育系之间以及衍生的不育系与不育系之间都具有等位点的温敏核不育基因。农垦58S及衍生的核不育系与安农S－1及衍生的核不育系之间没有等位点的核不育基因。     

籼型水稻温敏核不育系安湘S研究与应用概况

提　要: 安湘S(原名1356S)是以安农S-1不育基因源为供体国内第一批育成的实用型籼型温敏两用核不育系, 是目前生产上大面积应用的少数几个两用核不育系之一。本文对安湘S的育性温光反应特性、遗传模式、广亲和性及生理生化等方面的研究进行了综述; 简要概括了安湘S在两系法杂交水稻育种中的利用情况,并对其应用前景进行了展望。     

云南省首个利用标记不育系配制的高产杂交水稻新组合"云辐优26"

“云辐优26”系云南省首个利用苗期携带白化转绿型叶色标记的光温敏两系核不育系NHR 111S与强优异恢复系浙辐26配制而成的高产、抗病,具有自动排假功能的“放心”杂交水稻新组合,适宜在红河州内海拔1400m以下,边疆1350m以下的籼型杂交水稻及周边相似生态类型的籼型杂交水稻区域种植。     

淡绿叶色标记水稻光温敏核不育系开花习性

以4个淡绿叶粳稻光温敏核不育系和正常叶色粳型不育系浙农大11S(ZAU11S)及籼型不育系培矮64S(PA64S)共6个不育系为材料，在杭州自然条件下观察了上述6个光温敏核不育系的开花习性。结果表明：(1)淡绿叶色不育系同对照正常叶色不育系的叶色差异显著，易于肉眼分离；(2)淡绿叶色不育系的开花天数、开花率、柱头外露率都低于正常叶色不育系，日开花率、颖花张开时间和张开角度易受环境条件影响，表现较大差异；(3)除TS1外，其他三个淡绿叶色不育系在不育期和可育期的开花高峰都位于午前9：00或10：00，表现较强的早花特性。     

水稻隐性标记基因的发现及应用前景

具有隐性标记基因的黄化标8S，是2003年冬在海南三亚安农810S繁殖田发现的特异突变株。该材料从秧苗到收获的全生育阶段整个植株的全部叶片呈黄绿色。利用这一性状在亲本和杂种F1之间的不同表现，在秧苗期能正确区分真假杂种。对光温敏核不育系的防杂保纯、除杂去劣和苗期纯度鉴定等具有一定的实用价值。     

Influence of wheat leaf position on leaf rust severity

Summary The relation between flag leaf position and leaf rust severity was investigated in field experiments. Different leaf angles were obtained by attaching ends of flag leaves to strings stretched at different heights along wheat rows. Leaves with angles between lamina and stem of 0° and 45° were significantly less diseased than leaves with horizontal and pendulous positions. In the experiment with seedlings, spore settling and uredia number were significantly lower on erect than on horizontal leaves. The influence of wheat leaf position changes on leaf rust severity was discussed. It has been suggested that breeding of wheat cultivars with erect leaves can improve their resistance to airborne pathogens.     

大豆红叶斑病

由大豆生茎点霉(Phoma glycinicola)侵染引起的大豆红叶斑病主要在非洲发生.该病极具侵袭性,可造成50%～75%的大豆产量损失.病菌能在土壤中长期存活,抗逆性强,通过携带受污染的土壤、病组织及雨水等途径广泛传播.该病菌在中国无分布,一旦传入中国,极有可能使中国的大豆产业蒙受重大的经济损失.笔者描述了该病害的寄主、分布、症状、病原特征、侵染循环和病害控制方法,以期对提高边境口岸人员识别该病菌的能力、阻止大豆红叶斑病传入有所助益.     

Effect of leaf age on components of partial resistance in rice to leaf blast

Summary Ten rice genotypes were inoculated with a virulent isolate of Magnaporthe grisea to study the effect of leaf age on components of partial resistance, and evaluate associations between these components. The number of sporulating lesions per cm² leaf declined with increase of leaf age in all genotypes. The number of lesions per cm² leaf area in one week old leaves was about 25% that of the number in very young leaves in the susceptible cultivar CO39, but less than 2% in the more resistant cultivars IR36, IR60 and IR62. Large differences between genotypes were found for the number of sporulating lesions that developed, and this factor was closely related to the period that leaves remained susceptible after appearance. The number of lesions in the most susceptible cultivar CO39 was about 7 times that in the cultivars IR60 and IR64. Differences between genotypes were also found for lesion size. The effect of aging on average lesion size was less pronounced than on lesion density. Lesion size and lesion density were positively correlated, but a rapid decline of density was not necessarily accompanied by a rapid decline of size. No apparent differences between genotypes were observed for latent period. Genotypes with leaves that became highly resistant soon after appearance expressed higher levels of partial resistance in the field.     

Water-use efficiency, leaf area and leaf gas exchange of cowpeas under mid-season drought

Ten cowpea (Vigna unguiculata L. “Walp.”) genotypes were grown in a growth chamber under well-watered conditions up to early flowering and were then either subjected to water deficit or were continually well-watered. Water deficit was induced by withholding irrigation until the soil water potential was −75 kPa, which was then maintained for 10 days. Variation in water use efficiency (WUE), leaf area, specific leaf area (SLA), leaf area ratio (LAR) and leaf gas exchange (i.e. assimilation, transpiration, stomata conductance and internal CO₂ concentration) in response to water deficit were investigated. Water deficit treatment reduced mean water use by 21%. This caused between 11 and more than 40% reduction of biomass across the genotypes. Reductions in biomass were due to decline in leaf gas exchange and leaf area during water deficit. Water deficit improved the WUE of two genotypes (IFH 27-8 and Lobia) by approximately 20%, but caused moderate to huge reductions in most genotypes. High relative water content (RWC) of leaves was maintained in some of the genotypes by stomata closure and a reduction of leaf area. Drought avoidance by maintaining high leaf water content was negatively associated with leaf area as well as SLA. High assimilation rate under water deficit was associated with high RWC. Decline in assimilation rate were due mainly to stomata closure, however, some evidence of non-stomatal regulation were also found. WUE and instantaneous water use efficiency (IWUE, a molar ratio of assimilation to transpiration) were not directly associated, but IWUE and leaf internal CO₂ concentration (c_i) were negatively related while c_i was also moderately related with SLA. Overall, significant genotypic variations in leaf gas exchange parameters were found, which can give some indications of superiority when comparing cowpea genotypes for agronomic fitness under drought. The lack of relationship between WUE and IWUE was due to the instantaneous measurement of leaf gas exchange, which can be corrected by calculations to reflect the entire season.     

基于叶片面积玉米叶片保绿度开花后衰减特性初步研究

摘要：采用Excel工作表及Origin7.0统计分析软件对基于绿叶面积玉米叶片保绿度开花后衰减特性进行了初步研究,结果表明：玉米开花后叶片保绿度衰减符合方程y=aeb-cx/(1+eb-cx);不同基因型玉米叶片保绿度衰减启动时间、最大衰减速率和最大衰减速率出现时间等衰减特性差异较大;即使相同基因型在不同环境条件下叶片衰减特性也不尽相同。采用y=aeb-cx/(1+eb-cx)模拟方程能比较全面揭示叶片保绿度的动态变化过程。     

小麦旗叶衰老过程不同数学模型拟合比较及衰老特征分析

为了准确了解小麦叶片的衰老特征,筛选适合描述小麦叶片衰老过程的数学模型, 2011年和2012年分别以91个和105个小麦品种(系)为材料,用"S"型曲线中的Logistic、Gompertz和Richards模型拟合了试验品种叶片的衰老过程,解析了其叶片衰老特征。结果表明,试验品种可分为延绿、中等延绿、中等早衰和早衰4种类型。其旗叶衰老过程可分为衰老起始期、快速衰老期和衰老结束期3个阶段,3个阶段旗叶的衰老速度表现为"慢–快–慢",不同延绿类型品种开花后旗叶的绿色叶面积百分比下降主要在衰老过程的中后期。3种模型对不同延绿类型品种旗叶衰老过程均可以拟合,Gompertz和Richards模型拟合度接近,高于Logistic模型。Gompertz模型的拟合度以早衰中等早衰中等延绿延绿类型。不同延绿类型品种旗叶衰老曲线特征参数达到最大衰老速度时间(TMRS)、平均衰老速度(ARS)和绿色叶面积持续期(GLAD)存在显著差异, TMRS和GLAD以延绿中等延绿中等早衰早衰, ARS以早衰中等早衰中等延绿延绿。Gompertz模型对小麦叶片衰老过程的拟合度优于Logistic模型。叶片衰老过程特征参数可以用于品种延绿性差异评价。     

A leaf rust resistance gene, different from Lr34, associated with leaf tip necrosis in wheat

The gene Lr34 has contributed to durable resistance to leaf rust caused by Puccinia triticina in wheat worldwide. The closely associated leaf tip necrosis is generally used as the gene's marker. Lr34 has been postulated in many Indian bread wheat cultivars including ‘C 306’, based on the associated leaf tip necrosis and a few other field and glasshouse observations. The present study showed monogenic control of adult‐plant resistance in ‘C 306’ to leaf rust pathotype 77‐5 (121R63‐1). The F₂ segregation in the crosses between ‘C 306’ and the two known carriers of Lr34, ‘Line 897’ and ‘Jupateco 73’‘R’ fitted a digenic ratio. The F₃ families derived from the susceptible F₂ segregants were true breeding for susceptibility, proving the absence of Lr34 in ‘C 306’. The cross between ‘Line 897’ and ‘Jupateco 73’‘R’ did not segregate for susceptibility. Resistance in the cross ‘Agra Local’ (susceptible) × ‘C 306’ was associated with leaf tip necrosis, showing that the leaf rust resistance gene in ‘C 306’ was associated with leaf tip necrosis, but was different from Lr34. This gene is being temporarily designated as Lr‘C 306’. Hence, leaf tip necrosis cannot be considered as an exclusive marker for selecting Lr34 in wheat improvement.     

矮生菜豆叶片的解剖学观察

本试验采用石蜡切片技术和番红-固绿染色法对矮生和蔓生菜豆的叶片进行了解剖学研究,为选育优良的矮生菜豆品种提供理论依据。结果表明：矮生菜豆叶片下表皮的气孔数大于蔓生品种,且差异极显著。矮生品种叶片厚度、海绵组织厚度、海绵组织厚度/叶片厚度明显小于蔓生品种;而栅栏组织厚度/叶片厚度、栅栏组织厚度/海绵组织厚度则大于蔓生品种,叶片主脉维管束木质部导管数目、输水面积、韧皮部截面积均表现出矮生品种小于蔓生品种。因此,叶片的栅栏组织厚度/海绵组织厚度可以用于矮化菜豆的形态指标筛选。     

Effect on leaf photosynthetic rate by leaf blast for rice cultivars with different types and levels of resistance

Summary The effect of an inoculation with Pyricularia oryzae (isolate P06-6) on net leaf photosynthetic rate of rice (Oryza sativa) was studied with four cultivars. Measurements were taken on the sixth leaf of the main culm of plants in the early tillering stage. On cultivars CO39, IR50 and IR64 a susceptible infection type developed, but a clear difference in relative infection efficiency of the cultivars was observed. The highest number of lesions developed on leaves of CO39, whereas the lowest number was found on leaves of IR64. For all three cultivars the effect of a single lesion on the reduction in net leaf photosynthetic rate was found to be equal to a reduction in leaf area of three times the area occupied by the visible lesion. On IR68, a cultivar with complete resistance, brown specks of pinpoint size appeared without any effect on net leaf photosynthetic rate.     

The response to temperature of leaf area in tomato genotypes. II. The rate of leaf production

Summary Genotypic variation in the response to temperature of the rate of leaf production is reported. Leaf production was measured as the rate of successive leaves passing a specific length and by dissecting plants to obtain the rate of leaf initiation. These results together with the results of leaf size from the previous paper. are compared to the effect of temperature on the total leaf area. The use of information from these experiments in selecting for increased leaf area at low temperature is discussed.Guestworker Project Group Tomato Physiology.