耐阴稻种质资源快速筛选初步研究

根据水稻幼苗在黑暗下有保绿能力鉴定其耐阴性。以幼苗保绿面积比和保经程度为指标，从２３００份各类资源材料中筛选出耐阴性较强的ＨＲ６７９、金角粘、５６８５等５份籼型材料，０２４２８、５０６４９－５、Ｎ１３７７等６份粳型及籼型及籼粳中间型材料。保绿程度（ｙ）与保绿面积比（ｘ）呈极显著正相关，依据回归方程ｙ＝－０．０１７３＋０．７６３９ｘ预测保绿程度，进一步简化耐阴稻种资源大批量筛选技术。提出了利用耐阴种     

甬优系列杂交稻组合开花期耐冷性评价

以籼粳杂交稻甬优系列及杂交籼稻钱优2号和常规粳稻浙粳88为材料,于主茎见穗开花日起,用人工气候箱低温(17℃)和适温(25℃)分别处理4d和7d,以室外自然温度为对照,研究不同籼粳成分水稻低温胁迫下籽粒的结实特性。结果表明,低温处理显著降低甬优系列的籽粒结实率和穗重,低温胁迫效应以处理7d较大。按照耐冷性指数来划分,甬优538、浙粳88、甬优10号、甬优6号和甬优15号为耐冷型,甬优8号、甬优12号、甬优9号和甬优17号为冷敏感型,其余为中间型。此外,甬优系列耐冷型与冷敏感型籼粳成分并无明显的差异。进一步分析表明,低温处理7d,相对冷敏指数与水稻结实率和空粒率极显著相关(r=-0.9552,0.9602)。     

籼粳亚种F1的分类及其与杂种优势关系的研究

 采用程氏指数分类法对籼粳交亲本及其F₁分类结果，28个亲本基本可分籼粳两大类，广亲和品种多属偏籼偏粳型，与爪哇型品种接近。以籼稻为母本的籼粳交F1籼型较多，约占73.1%， 以粳稻为母本的籼粳交F₁粳型较多，约占72.4%。92个籼粳交组合F₁偏籼、偏粳型比例为73.9%，这说明F₁分类既受细胞质影响，也受双亲遗传背景影响。双亲程氏指数差值与F₁结实率呈极显著的负相关，而与F₁的生物产量呈极显著正相关，双亲程氏指数差值大小适合(6-13)时， 生物产量与结实率均较高，其经济优势较强。     

小麦面粉特性与饺子品质关系研究

为给饺子专用小麦品种的品质改良提供参考依据,选用黄淮麦区的主要品种（系）24份,研究了面粉蛋白质含量、灰分含量、粉质和快速黏度分析仪（RVA）参数对饺子皮颜色和感官评价的影响。结果表明,面粉品质性状对鲜饺子皮颜色的影响大于熟饺子皮,面粉灰分含量与24 h鲜饺子皮亮度L*值呈极显著负相关（r=-0.53）,蛋白质含量与0 h鲜饺子皮亮度L*值呈显著负相关（r=-0.46）。形成时间和稀懈值对0 h鲜饺子皮红度a*值有显著正向影响（r=0.49和0.47）,最终黏度对0 h鲜饺子皮红度a*值有显著负向影响（r=-0.43）。吸水率对24 h鲜饺子皮黄度b*值有显著正向影响（r=0.49）,耐揉指数对24 h鲜饺子皮的b*值有极显著负向影响（r=-0.75）。粉质仪和RVA参数对饺子皮感官评价有显著影响,其中耐揉指数与饺子皮表面状况和风味呈极显著负相关（r=-0.64和-0.61）,与饺子皮弹性和总分呈显著负相关（r=-0.42和-0.49）,形成时间与饺子皮硬度呈显著负相关（r=-0.41）,反弹值与饺子皮弹性呈极显著负相关（r=-0.57）,峰值黏度与饺子皮弹性和光滑性呈显著正相关（r=0.42和0.41）,稀懈值与饺子皮光滑性呈显著正相关（r=0.43）。制作优质饺子要求面粉具备相对较低的蛋白含量、灰分含量、耐揉指数、形成时间和反弹值,相对较高的峰值黏度和稀懈值。     

孕穗期冷水胁迫对寒地水稻干物质生产的影响

以黑龙江省30份主栽水稻品种或品系为试材,在孕穗期设置17℃冷水灌溉处理(20d),以常规栽培管理为对照,分析冷水胁迫对水稻干物质生产的影响。结果表明,冷水胁迫导致所有试材每穴实粒数、结实率、千粒重和产量下降,并根据相对结实率将试材耐冷性分为1、3、5、7和9级,以7和9级最多,1级最少,分别占总材料的30%和10%。在冷水处理下,全部材料抽穗期至成熟期干物质积累量及比例、群体生长率、净同化率、粒叶比、收获指数、叶面积指数、剑叶叶基角、剑叶和倒2叶与倒3叶披垂度均下降,但高效叶面积率增加。相关分析表明,冷水处理的相对结实率与收获指数(r=0.96**)、产量(r=0.91**)、粒叶比(r=0.84**)和干物质积累量(r=0.48**)的冷水反应指数(CRI)呈极显著正相关,与群体生长率(r=0.44*)、净同化率(r=0.44*)和干物质积累比例(r=0.43*)的CRI显著正相关。综上,孕穗期冷水胁迫对水稻干物质生产的影响在品种间存在很大差异,在冷水胁迫下耐冷性极强品种(系)干物质积累量及比例、群体生长率、净同化率、粒叶比和收获指数对冷水反应迟钝,这是耐冷性极强品种(系)保持较高产量的重要形态特征和生理原因。     

江苏省杂草稻的传播与籼粳分化研究

21世纪初,杂草稻仅在江苏省局部区域发生,目前已扩大到全省,并对粳稻的高产和稳产造成严重威胁。为了掌握其快速发生机制,便于杂草稻的防除工作,需要进一步明确江苏省13市杂草稻是独立发生还是相互传播,以及江苏省杂草稻籼粳地理分布。采集了江苏省13个市58个样地的58个种群,总计205份的杂草稻样品。所有样品在南京农业大学江浦农场田间种植,并测量了38个形态学性状和6个程氏指数鉴别性状。欧氏距离聚类分析,表明江苏省13个市的杂草稻是相互混杂的。籼粳地理分布表明,江苏省杂草稻主要以籼型和偏籼型为主,籼型和偏籼型杂草稻在全部58个样点中都有分布,分别占样品总量的54.15%和42.40%;偏粳型和粳型仅分布于6个样点(淮安、苏州、盐城与扬州),分别占样品总量的2.93%和0.48%。此外,对比江苏省杂草稻的籼粳地理分布与江苏省地方品种的籼粳地理分布,未显示对应关系。籼粳比例和地理分布揭示了江苏省杂草稻主要为籼型,其中极少数为粳型杂草稻,粳型杂草稻的比例与杂草稻和栽培稻之间的自然基因漂移比例相近。     

籼粳交重组自交系的亚种属性与稻米品质性状的关系

2006—2007年以典型籼稻七山占和典型粳稻秋光构建的重组自交系(RILs)F8的92个株系和F9的142个株系为试材,分别以程氏指数(ChI)和籼粳特异SSR标记(Dj)为群体形态分化与遗传分化的指标,同时测定11项主要稻米品质性状,分析群体稻米品质性状类型间差异及籼粳属性与稻米品质性状的相关性。结果表明,两世代RILs群体形态分化均表现为接近正态的连续分布,籼型和粳型株系数接近,遗传分化则均表现为明显偏粳的连续分布;根据ChI将RILs群体划分为籼型和粳型,除F9粒宽外两世代品质性状类型间差异均未达到显著水平;根据Dj将RILs群体划分为偏粳型和粳型,两世代粳型糙米率、整精米率、粒宽显著或极显著高于偏粳型,长宽比极显著低于偏粳型;两世代RILs群体ChI与所有品质性状的相关性均未达到显著水平;Dj与糙米率、整精米率和粒宽呈显著或极显著正相关,而与长宽比呈显著或极显著负相关。形态分化与北方粳稻品质性状没有直接关系,而遗传分化中粳稻血缘比例增加可能通过粒形间接改善碾磨品质。     

特异性SSR标记对水稻籼粳交RIL群体的分类研究

以七山占(典型籼稻)×秋光(典型粳稻)F8重组自交系群体为试材,用形态指数法和分子标记法对该群体的籼粳分化进行研究。结果表明:重组自交系群体由籼到粳呈偏粳的连续变化,与形态指数法相比,分子标记法判断该重组自交系群体更加偏粳;两种分类方法的符合度仅在50%左右;籼粳交后代群体的非随机组合值较低,其平均值R2=0.019。     

浙江省早稻品种（系）的抗裂性分析

针对稻谷的吸湿性裂纹特性,设计了标准处理方法,并对参加浙江省“9410”计划联合品比试验的品系、部分早籼及早粳育种亲本进行抗裂性分析和等级评定。裂纹粒率最高的材料达73%,最低的仅0.5%,材料间差异显著（P=4.23×10-16<0.01）;其中,45份籼稻材料平均裂纹粒率为34.19%,8份粳稻材料平均裂纹粒率为55.44%,2份长粳材料平均裂纹粒率为2.25%。相关分析表明,品种的抗裂性与粒形呈极显著正相关（r=0.49**）。     

水稻两用核不育系广占63S与籼粳型父本配组杂种F_1产量性状与产量关系研究

利用光温敏两用核不育系广占63S分别和籼、粳型父本测交配组,通过对2种类型F1代的产量性状表现的比较,对2种组配方式32个F1组合的单株产量与产量性状的关系进行相关分析,并对产量性状对单株产量进行了通径分析。结果表明,广占63S与籼型父本配制的组合在结实率和千粒重上优势明显,其单株穗数和单株产量呈极显著正相关,结实率和单株产量呈显著正相关;粳型父本配制组合的结实率和单株产量呈极显著正相关,每穗粒数和单株产量呈显著正相关。2种组配方式后代组合产量性状对单株产量的直接作用也不相同,进而提出了利用广占63S与籼型材料配组比直接利用粳型材料配组更有利于选育出强优势实用型杂交组合。     

水稻苗期耐热种质资源筛选及QTL定位

[目的]鉴定和筛选水稻极端耐热种质或基因,为培育耐高温水稻新品种提供技术支撑.[方法]以耐热等级和幼苗存活率为指标对不同类型水稻苗期耐热性进行鉴定评价,以筛选和鉴定耐热种质资源及主效QTL.[结果]不同类型水稻品种苗期耐热性存在明显差异,籼稻品种耐热性明显强于粳稻品种,籼稻和粳稻品种均存在极端耐热和极端敏感种质资源;共...     

Genetic Diversity of Rice Landraces from Lowland and Upland Accessions of China

Genetic diversity of rice landraces from lowland and upland accessions of China was investigated using 66 polymorphic simple sequence repeat (SSR) markers.The total number of alleles detected from all 324 tested accessions was 555 with an average allele number (Na) of 8.409 per locus,the average effective number of alleles (Ne) of 3.574 and the average Shannon’s information index (I) of 1.378.The genetic diversity was higher for the indica landraces compared to the japonica landraces,and the upland landraces were more genetically diverse than the lowland landraces.The SSR markers,RM72,RM232,RM219,RM241,RM224 and RM3 showed the highest rates of polymorphism and these SSR markers were suitable to assess the genetic diversity of rice germplasm resources.A dendrogram of 324 accessions of lowland and upland landraces showed that all rice accessions were mainly subdivided into two groups,japonica and indica,with some being intermediate.The distribution of lowland and upland landraces among the japonica and indica rice groups was distinct,with obvious differentiation between the lowland and upland landraces in japonica rice,but no such clear distinction in indica rice.     

Genetic diversity and association mapping for salinity tolerance in Bangladeshi rice landraces

Breeding for salinity tolerance using Bangladeshi rice landraces and understand genetic diversity has been limited by the complex and polygenic nature of salt tolerance in rice genotypes. A genetic diversity and association mapping analysis was conducted using 96 germplasm accessions with variable response to salt stress at the seedling stage. These included86 landraces and 10 indica varieties and lines including Nona Bokra, from southern Bangladesh. A total of 220 alleles were detected at 58 Simple Sequence Repeat(SSR) marker loci randomly distributed on all 12 rice chromosomes and 8 Sequence Tagged Site(STS) markers developed for genes SKC1, DST, and SalT. The average gene diversity was 0.5075 and polymorphism information content value was 0.4426, respectively. Cluster analysis revealed that 68 and 21 accessions were clustered into 2 distinct groups, possibly corresponding to indica and japonica groups, respectively and the remaining 7 landraces were classified as an admixed group. In addition to Wn11463, the STS marker for SKC1, RM22418 on Chr. 8 was significantly associated with salinity tolerance, at the location of a QTL detected in previous studies. Our findings of favorable alleles associated with salinity tolerance in Bangladeshi rice landraces, as well as the development of STS markers for salt tolerance genes, will be helpful in future efforts to breed salinity tolerance in rice.     

Genetic Diversity and Relationship of Weedy Rice in Taizhou City, Jiangsu Province, China

Microsatellite markers and morphological charactedstics were used to explore the genetic diversity and possible origin of weedy dce in Taizhou City, Jiangsu Province, China. Fifty-two weedy rice (Oryza sativa L.) accessions were compared with two wild rice, four hybdd rice and five cultivars using 22 simple sequence repeat (SSR) primer pairs. A total of 107 fragments were amplified, averaging 5.6 alleles per primer pair. The polymorphic index content (PIC) values ranged from 0.3077 to 0.7951, averaging at 0.5870. The average genetic distance of all samples ranged from 0.02 to 0.46 with an average of 0.262. The genetic distance among Taizhou weedy rice ranged from 0.03 to 0.44 with an average of 0.224. Cluster analysis showed that all the weedy rice accessions from Taizhou City were indica, and could be subdivided into different genotypes. The majority (86%) of weedy rice was most closely related to hybrid rice. The Taizhou weedy dce accessions were morphologically similar, but still could be delineated into indica or japonica group by some morphological traits. it is suggested that the levels of genetic and morphological diversities of weedy rice in Taizhou City are low and these weedy rice plants originated from the segregating progenies of hybrid rice that had naturally introgressed with cultivated rice.     

Differential tolerance of weedy red rice (Oryza sativa L.) from Arkansas, USA to glyphosate

Red rice (Oryza sativa L.), a weedy relative of cultivated rice (O. sativa), is a troublesome weed in rice in the southern United States. It is also very problematic in other world regions where rice is grown. There are many types of red rice. Some have white pericarp. In this paper, the term ‘red rice’ will be used to refer to the weedy types that occur in this region of the southern USA. Because of the great diversity in morphology and phenology of red rice populations in the USA, we hypothesized that these have differential tolerance to glyphosate. Red rice is subjected to selection pressure by glyphosate, which is the principal herbicide used in glyphosate-resistant soybean planted after rice. Two hundred-fifteen red rice accessions were collected in Arkansas, USA between 2002 and 2003 and evaluated for glyphosate tolerance between 2003 and 2006. The commercial dose of glyphosate controlled red rice accessions 81-100% regardless of application timing, by 30 d after treatment. The number of survivors that produced seeds and the seeds produced per survivor differed between accessions. Application of the full dose at the tillering stage was more effective than at the 3- to 4-leaf stages. At half the field dose, 40 to 54% of survivors produced seed, with germination capacity of 30-100%. The lowest dose of glyphosate, 225 g a.e. ha⁻¹, resulted in the widest range of control ratings from 30 to 100%. The red rice accessions differentiated into six tolerance categories. A tolerance map was generated and will be used in educating growers about the proper use of glyphosate for red rice management.     

猪屎豆种质资源萌发期的耐旱性评价

为筛选耐旱性强的优异猪屎豆种质,本研究采用质量分数为15%的聚乙二醇（PEG-6000）溶液模拟干旱环境,以相对发芽势、相对发芽率、萌发耐旱指数、相对胚根长、相对苗高和活力指数作为评价指标,利用隶属函数法对228份猪屎豆种质资源的萌发期耐旱性进行综合评价。根据6个评价指标的平均隶属函数值将猪屎豆资源的耐旱性分为5个等级,其中耐旱等级为Ⅰ级的种质1份,来源于云南元江,平均隶属函数值为0.8;Ⅱ级种质13份,0.6≤平均隶属函数值<0.8;Ⅲ级种质105份,0.4≤平均隶属函数值<0.6;Ⅳ级种质105份,0.2≤平均隶属函数值<0.4;Ⅴ级种质4份,其平均隶属函数值小于0.2。     

云南地方稻核心种质孕穗期耐冷性及其地理分布

 以云南16个地州和5个稻作区为单位，对477份云南稻种核心种质进行了耐冷性鉴定及其地理分布研究。结果表明：（1）低温条件下花药长与结实率呈极显著正相关（0.588[sup]**[/sup]），温室条件下两者关系不大（0.080）。（2）低温条件下不同稻作区云南稻种核心种质孕穗期耐冷性差异较大，滇西北高寒粳稻区的稻种核心种质孕穗期耐冷性最强，南部边缘水陆稻区最弱。而温室条件下基本未受到冷害，结实率接近或超过70%。因此，耐冷育种目标和品种因稻区而异。（3）低温条件下不同地州云南稻种核心种质孕穗期耐冷性差异十分明显，而温室条件下基本未受到冷害，结实率均大于65%。根据稻种核心种质的结实率降低率及其地州间的自然气候差异，可将16个地州划分为重冷害区、冷害区和轻冷害区。（4）不同稻作区或不同地州间云南稻种核心种质孕穗期耐冷性的差异，进一步揭示了由海拔和纬度差异引起的温度变化不仅是籼粳分化的主导因子,也是造成籼粳两个亚种六大生态群之间差异和云南稻种遗传多样性大的根本原因，同时也是耐冷基因形成的关键因素，孕穗期耐冷性是云南地方稻种与地州或稻作区低温长期协同进化的结果。     

稻属AA染色体组8个种间SSR多样性与亲缘关系

选用平均分布于水稻基因组的30对SSR 引物,对AA染色体组8个野生稻种共42份材料的遗传多样性及遗传关系进行了研究。结果显示,本试验选取的30个SSR标记均具有多态性,多态性位点百分率为100%。30个多态性位点共扩增出的等位基因数为224, 每个位点可扩增出3～10个等位基因,平均7.47个;等位基因有效数(Ae)变幅为1.25～891,平均5.45。多样性指数中,Shannon多样性指数(I)为0.454～2.386,平均1.826;而Nei基因多样性指数变幅为0.199～0.888,平均0.774。系统聚类和带型分析结果表明,亚洲栽培稻(Oryza sativa) 与普通野生稻(O. rufipogon) 的亲缘关系最近,非洲栽培稻(O. glaberrima) 则与巴蒂野生稻(O. barthii) 关系最为密切,杂草稻(O. spontanea) 与普通野生稻 (O. rufipogon)、亚洲栽培稻(O. sativa) 之间有较近的亲缘关系,而展颖野生稻(O. glumaepatula)、长雄蕊野生稻(O. longistaminata)与AA组其他稻种之间的亲缘关系较远。     

Morphological and Molecular Characterization of Novel Salt-Tolerant Rice Germplasms from the Philippines and Bangladesh

To screen for new sources of salinity tolerance, 688 traditional rice varieties from the Philippines and Bangladesh were obtained, and their tolerance to hypersaline conditions at the seedling stage was examined. A total of 29 Philippine lines and 15 Bangladeshi lines were scored as salt-tolerant.Morphological assessment(plant height, biomass and Na-K ratio) revealed that among the 44 salt-tolerant accessions, Casibon, Kalagnon and Ikogan had significantly higher relative shoot length difference, relative shoot growth reduction and shoot Na-K ratio than the tolerant check FL478.Additionally, AC and Akundo exhibited significantly higher Na-K ratios than the other genotypes. The genetic diversity of the 44 genotypes was assessed using 34 simple sequence repeat markers. A total of 133 alleles were detected across all loci. Cluster analysis showed that AC, Akundo and Kuplod were clustered along with FL478, indicating a strong genetic relatedness between these genotypes. IR29(susceptible check) was singly separated. The haplotype analysis revealed that none of the 44 genotypes had a similar allele combination as FL478. These accessions are of interest since each genotype might be different from the classical salinity-tolerant Pokkali.     

Rice landrace diversity in Nepal: Variability of agro-morphological traits and SSR markers in landraces from a high-altitude site

Nepal has a wide diversity of rice landraces in all rice-growing areas from low to high altitude. A baseline survey in Jumla, a high-altitude site (2200–3000 m), identified rice landraces with different names that differed in phenotype and were adapted to the extreme high-altitude environment. Jumli Marshi was the most common traditional rice variety, accounting for 85% of samples collected. The genetic diversity of these landraces was assessed by agro-morphological variability and microsatellite marker polymorphism. Forty-two qualitative and quantitative traits and 39 microsatellite (simple sequence repeats, SSR) markers were assessed among accessions with 10 different names. The accessions showed low morphological diversity with an average Shannon Weaver diversity index of 0.23. Only 16 morphological traits showed significant variation among the accessions. Discriminant function analysis showed that only 36% of accessions could be clustered according to name by morphological traits. Only one SSR locus was polymorphic, distinguishing only one accession. The names used by farmers to describe the phenotypic characteristics of panicle and grains were inconsistent indicators of genetic identity. We conclude that the Jumla landrace population has a narrow genetic base. The diversity detected was sufficiently low for it to be possible that there was a single origin for all of the Jumla landraces.