Correlation between Stigma Characteristics and Outcrossing Rate of Five Photo-thermo Sensitive Genic Male Sterile(PTGMS) Rice Lines

[Objective] This study aimed to investigate the correlation between stigma characteristics and outcrossing rate of photo-thermo sensitive genic male sterile（PTGMS） rice lines. [Method] The stigma exsertion rate, stigma size and stigma vitality of Chuang 5S, Yun 9S, Peiai 64 S, P88 S and Y58 S were analyzed. Using R608 as a male parent, outcrossing rate of these five PTGMS lines was determined. [Result]There were differences in stigma exsertion rate, stigma size and stigma vitality among five PTGMS lines. P88 S exhibited the best stigma characteristics and relatively strong stigma vitality, with the stigma exsertion rate of 95.94%, stigma vitality coefficient of 2.71, outcrossing rate of 84.02% in the field. Peiai 64 s had the minimum stigma length（2.41 mm） and stigma width（1.10 mm） and the weakest stigma vitality, with the stigma exsertion rate of 93.04%, outcrossing rate of 65.47%. Yun 9S,Y58 S and Chuang 5S displayed medium stigma characteristics, among which Yun9 S exhibited higher outcrossing rate than other two PTGMS lines. Correlation analysis showed that stigma exsertion rate, stigma length, stigma width, stigma area and stigma volume were significantly correlated to outcrossing rate（P〈0.05）, with correlation coefficients of 0.897, 0.934, 0.934, 0.939 and 0.937, respectively. However,there was no significant correlation between stigma vitality coefficient and outcrossing rate. [Conclusion] Based on stigma characteristics of five PTGMS lines, auxiliary pollination measures should be adopted reasonably to save production costs and improve hybrid rice seed yield.

Breeding and Utilization of Japonicalinous CMS Line Chunjiang 19A with Wide Compatibility and High Outcrossing Rate

[Objective] To breed and utilize the japonicalinous cytoplasmic male sterile （CMS） line Chunjiang 19A with wide compatibility and high outcrossing rate. [Method] Cbunjiang 16A was used as the female parent to cross with Indica-Japonica crossing material B125, which was used as male parent. Backcross breeding was contin- ued for consecutive generations to breed the CMS lines with wide compatibility and high outcrossing rate. [Result] Chunjiang 19A is a late medium Japonica CMS line with good fertility stability. The proportion of sterile plants and pollen abortion rates are 100% and the Cheng＇s index is 14. It is the japonicalinous CMS line with early flowering, partial stigma exsertion, high outcrossing rate, wide compatibility, high re- sistance to stripe disease and good combining ability. The hybrid rice combinations originated from Chunjiang 19A have strong tUlering ability, dominant heterosis, high resistance to stripe disease, great yield potential and good color change at mature stage. [Conclusion] The successful breeding of Chunjiang 19A laid good foundation for the breeding of Japonica hybrid rice and Indica-Japonica hybrid rice combinations with high seed production and dominant heterosis, showing a promising application prospect.

Effect of High Temperature on Outcrossing Characteristics at the Fertility Sensitive Period of Photo-thermo Sensitive Genic Male Sterile (PTGMS) Rice Lines

Four sterile lines （Peiai64S, Y58S, Guangzhan 63-2S and H638S） and the restoring line R527 were used as materials. Five temperature gradients （24, 27, 30, 33 and 36 ℃ in artificial climate chamber） and the natural temperature （as control） were treated to the four sterile lines for 6 d in the fertility sensitive period of heading to flowering stage, respectively, to study the effects of temperature on physiological biochemical characteristics of young panicles and outcrossing characteristics. The results showed that the percentages of exerted stigma of Peiai 64S and Y58S were the highest at 27 ℃, which were 86.81% and 86.06%, respectively, while the percentages of exerted stigma of Guangzhan 63-2S and H638S were the highest at 24 ℃, which were 76.24% and 81.76%, respectively; the stigma viability of Peiai 64S, Y58S, Guangzhan 63-2S and H638S were the best at 24 ℃, which were 1.96, 2.12, 1.74 and 1.94, respectively; the outcrossing rates of Peiai 64S, Guangzhan 63-2S and H638S were the highest at 24 ℃, which were 58.87%, 54.22% and 50.50%, respectively, while the outcrossing rate of Y58S was the highest at 27 ℃, which was 58.96%; and the contents of peroxidase （POD） of the four sterile lines increased significantly at 33 ℃ compared with the control, while the contents of malondialdehyde （MDA） and proline increased significantly at 36 ℃ compared with the control. There were differences in temperature sensitivity between the male sterile lines, and the 24 ℃ treatment during the sensitive period was the best for the fertility sensitive period of Peiai 64S, while 27 ℃ was the best temperature for Y58S, Gangzhan 63-2S and H638S.

A microsatellite study on outcrossing rates and contamination in an Eucalyptus globulus breeding arboretum

Four pairs of microsatellite molecular polymorphism primers were used to analyse microsatellite fingerprints of 188 seedlings derived from an open-pollinated progeny grafted Eucalyptus globulus breeding arboretum in Victoria, south-eastern Australia. The microsatellite loci chosen for this study were highly polymorphic with the mean number of alleles per locus of 14.25. Individual mothers varied in their outcrosssing rate estimate from 15% to 95%, the overall outcrossing level in the arboretum was 47.9% and the contamination rate was 17.6%. The high selfing level was likely to result in marked inbreeding depression in the performance of open-pollinated seed lots. Open-pollinated seeds collected from such arboreta are not advisable because of its low genetic quality, although such arboreta may be useful for the seed production through large-scale manual pollination or collecting seeds only from trees or genotypes within the arboretum that have high outcrossing rates.

Genetic effects and plant architecture influences on outcrossing rate in soybean

Outcrossing rate is an important determinant of cytoplasmic male sterile(CMS)breeding and hybrid seed production for heterosis in soybean.Parental lines with a high outcrossing rate were screened for backcross breeding to obtain the high outcrossing rate maintenance B-lines and sterile A-lines.Application in production practices will help to increase hybrid soybean production.In this study,JLCMS82B and JLCMS89B were selected as parents for the construction of outcrossing rate segregation populations,and the progeny-array approach(PAA)and glyphosate resistant gene markers were used to determine outcrossing rates.We found that:(1)The outcrossing rate between JLCMS82B and JLCMS89B was significantly different;(2)the outcrossing rate of the F2 segregating populations was a quantitative trait,though whether an additive or epistatic effect exists required analysis with a triple test intersection analysis;(3)agronomic traits correlated with outcrossing rate;outcrossing rate was the highest with plant height of about 84 cm,lower number of plant branches,earlier flowering time,larger angle between the branches and the main stem,and with more divergent plant morphology.Correlation analysis between agronomic traits and outcrossing rate can effectively guide the screening of parents with a high outcrossing rate.

New Temperature Sensitive Genic Male Sterile Lines with Better Outcrossing Ability for Production of Two-Line Hybrid Rice

An investigation was carried out with three newly developed temperature sensitive genic male sterile （TGMS） lines for their floral traits, seed production potential and outcrossing ability in ten cross combinations. In the TGMS lines, fertile pollens had an average diameter of 0.89 mm while the sterile pollens was with 0.02 mm diameter.TS-29-150GY produced the biggest fertile pollens with 0.92 mm and other two lines produced relatively smaller pollens with 0.91 and 0.85 ram. Pollen fertility during the fertility reversion period was an average of 60.7%. TS-29-150GY had the maximum of 66.9% spikelet fertility whereas other two lines （TNAU18S and TNAU60S） had relatively lower spikelet fertility of 27.8% and 26.7%, respectively. Average of 17.00 g of seed yield was obtained in the TGMS lines during the fertility reversion period. TS-29- 150GY had the highest value of 21.20 g of seed yield while TNAU18S and TNAU60S produced 16.6 g and 13.2 g of seed yield, respectively. The low seed production ability of these three TGMS lines was attributed only to the environmental conditions prevailing during the period. All three TGMS lines had considerable outcrossing potential of 41.2%, 24.6% and 25.0%, respectively. The cross combinations viz. TNAU18S/IET21508 （36 g/plant）, TNAU18S/IET21044 （13 g/plant）, TNAU18S/IET21009 （26.5 g/plant）, TNAU60S/CB-09-106 （26.2 g/plant）, TNAU60S/IET21009 （14 g/plant） and TS29-150-GY/DRR 3306 （39.2 g/plant） showed perfect synchronization with acceptable hybrid seed yield, indicating suitability of TGMS system under Indian condition. Based on the outcrossing related traits viz. panicle exertion, angle of glume opening, stigma length and pollen size, TNAU18S was identified as the best, followed by TS-29-150GY.

Factors Influencing the Outcrossed Seed-Setting Obstacles of Photo-thermo Sensitive Genie Male Sterile Rice

Using photo-thermo sensitive genie male rice (PTGMS) Pei' ai 64S, W7415S, W6154S, N26S, Annong S, Nongken 58S, 7001S and 5088S as female parents and conventional indica lines 8258 and U89 as male parents, the factors affecting outcrossed seed-setting were analyzed. The PTGMS had obstacles in outcrossed seed setting influenced by inheritance and environment at varying degrees. Environmental temperature was regarded as the main factor that resulted in the outcrossed seed-setting obstacles. The sensitive stage was at the early stage of grain filling for outcrossed seed setting. There existed remarkable differences at the sensitivity stage, the duration of sensitive period, the sensitive level and the effective level of outcrossed seed-setting obstacles caused by environmental temperature among different PTGMS lines. Therefore, attention should be paid to outcrossed seed-setting obstacles in selection and utilization of PTGMS lines.

OcBSA:An NGS-based bulk segregant analysis tool for outcross populations

Constructing inbred lines for self-incompatible species and species with long generation times is challenging,making the use of F1 outcross/segregating populations the main strategy for genetic studies of such species.However,there is a lack of dedicated algorithms/tools for rapid quantitative trait locus(QTL)mapping using the F1 populations.To this end,we have designed and developed an algorithm/tool called OcBSA specifically for QTL mapping of F1 populations.OcBSA transforms the four-haplotype inheritance problem from the two heterozygous diploid parents of the F1 population into the two-haplotype inheritance problem common in current genetic studies by removing the two haplotypes from the heterozygous parent that do not contribute to phenotype segregation in the F1 population.Testing of OcBSA on 1800 simulated F1 populations demonstrated its advantages over other currently available tools in terms of sensitivity and accuracy.In addition,the broad applicability of OcBSA was validated by QTL mapping using seven reported F1 populations of apple,pear,peach,citrus,grape,tea,and rice.We also used OcBSA to map the QTL for flower color in a newly constructed F1 population of potato generated in this study.The OcBSA mapping result was verified by the insertion or deletion markers to be consistent with a previously reported locus harboring the ANTHOCYANIN 2 gene,which regulates potato flower color.Taken together,these results highlight the power and broad utility of OcBSA for QTL mapping using F1 populations and thus a great potential for functional gene mining in outcrossing species.For ease of use,we have developed both Windows and Linux versions of OcBSA,which are freely available at:https://gitee.com/Bioinformaticslab/OcBSA.

Genome-wide identification of agronomically important genes in outcrossing crops using OutcrossSeq

Many important crops(e.g.,tuber,root,and tree crops)are cross-pollinating.For these crops,no inbred lines are available for genetic study and breeding because they are self-incompatible,clonally propagated,or have a long generation time,making the identification of agronomically important genes difficult,particularly in crops with a complex autopolyploid genome.In this study,we developed a method,OutcrossSeq,for mapping agronomically important loci in outcrossing crops based on whole-genome low-coverage resequencing of a large genetic population,and designed three computation algorithms in OutcrossSeq for different types of outcrossing populations.We applied OutcrossSeq to a tuberous root crop(sweet potato,autopolyploid),a tree crop(walnut tree,highly heterozygous diploid),and hybrid crops(double-cross populations)to generate high-density genotype maps for the outcrossing populations,which enable precise identification of genomic loci underlying important agronomic traits.Candidate causative genes at these loci were detected based on functional clues.Taken together,our results indicate that OutcrossSeq is a robust and powerful method for identifying agronomically important genes in heterozygous species,including polyploids,in a cost-efficient way.The OutcrossSeq software and its instruction manual are available for downloading at www.xhhuanglab.cn/tool/OutcrossSeq.html.

Family Outcrossing Rates of Pinus caribaea Morelet var. caribaea in Seed Orchard and Natural Populations

Family outcrossing rates of Pinus caribaea var. caribaea populations that differed in origin and management were estimated by using isozyme markers. The family outcrossing rates were estimated by (1)fixing the probability of pollen gene frequency (p); (2) allowing pollen gene frequency to vary among families. The estimates of family outcrossing rates for all the populations varied widely among families (clones of the seed orchard), ranging from 0.39 to 2.0. The average family outcrossing rates of both m...

牛蒡繁育系统与花部特征研究

[目的]了解牛蒡生殖特性,为其栽培育种提供理论基础。[方法]通过野外观察,运用异交指数(OCI)、花粉胚珠比(P/O)及套袋试验等研究方法对大连地区辽宁中医药大学内牛蒡的花部特征及繁育系统进行研究。[结果]牛蒡群体花期一般为34~35 d,花期重叠,每年6月下旬开始到7月末结束,其花粉和柱头具有活力且柱头在全天都具有活力;OCI为4,P/O为5 666,异花授粉需要传粉者,风对其传粉作用不明显;套袋试验中自然套袋与自然对照均可结实,结实率分别为99.0%和69.5%,去雄去柱头后套袋结实率为0,不具有无融合生殖特性。[结论]牛蒡具有异交特性且自花授粉可结实,风媒传粉可能性小。

春季开花植物膜苞鸢尾的花部综合征与繁育系统研究

膜苞鸢尾(Iris scariosa)为鸢尾科鸢尾属的多年生春季开花植物,具有重要的观赏价值。为了探究该物种的花部综合征和繁育系统特性,促进其杂交选育和种质资源挖掘利用,该研究以膜苞鸢尾为研究材料,采用野外观测和控制性实验相结合的方法,对其开花物候、花部综合征、繁育系统及传粉特性等方面进行了研究。结果表明:(1)该物种于5月初进入始花期,5月中旬进入盛花期,5月下旬进入末花期,开花持续时间为16 d。(2)花为蓝紫色,具有特殊气味和少量花蜜,单花花期为2.5~3.0 d。(3)人工授粉实验结果表明,该物种属于专性异交的繁育系统,不存在无融合生殖和自主自交能力。(4)该物种属于泛化传粉系统,意大利蜜蜂、中华蜜蜂、隧蜂是主要传粉者,访花频率分别为(0.57±0.05)、(0.42±0.04)、(0.19±0.03)times·flower^(-1)·h^(-1)。膜苞鸢尾花具有的艳丽颜色、较大的花展示、昆虫访花高峰期与花粉活力最高时期及柱头最佳授粉期相吻合,外花被片中脉上的黄色须毛状附属物等特征对保证其传粉过程的顺利完成并促进异交繁殖成功具有重要意义。该研究结果为膜苞鸢尾的资源利用与种质创新提供了重要的理论资料。

BS型小麦光温敏雄性不育系柱头外露规律研究

BS型小麦光温敏雄性不育系的开花习性影响其异交性能,进而影响杂交小麦制种产量。为了明确柱头外露对不育系异交结实的影响,以15个不育系为材料,同时选取3个配合力好、制种性状优良的恢复系作为父本,研究不育系从始花期开始连续10 d柱头外露率的变化规律及其与异交结实的相关性。结果表明,不育系在开花过程中柱头外露率基本呈先升后降的变化趋势。在盛花期,柱头外露主要集中在中部穗位。柱头外露性状较好的不育系为BS278-2、BS163、BS366、BS210。相关性分析结果表明,柱头外露率与柱头外露小花异交结实率呈极显著正相关。综上说明,柱头外露是影响不育系异交结实的重要因素之一,在制种时选择具有柱头外露性状的不育系可提升制种产量。以上研究结果为高异交光温敏不育系的选育提供了科学依据。

BS型小麦光温敏雄性不育系开颖规律研究

BS型小麦光温敏雄性不育系的异交性能直接影响杂交小麦的制种产量,而开花习性是衡量不育系异交性能的重要指标。为了明确开颖率、开颖角度对不育系异交结实率的影响,本研究以15个不育系为材料,同时选取3个配合力好、制种性状优良的恢复系作为父本,分析了不育系在开花过程中开颖率和开颖角度的变化规律及其与异交结实率的相关性。结果表明,在开花过程中,不育系开颖率基本都呈先升后降的变化趋势,且中部和上部穗位开颖较早,但在盛花期,下部穗位开颖角度较大且开颖主要集中在中部穗位,开颖性状较好的不育系为BS278-2、BS185、BS126、BS163、BS136。相关性分析表明,开颖率与开颖小花异交结实率呈极显著正相关,开颖角度与异交结实率呈显著正相关。这说明开颖性状是影响不育系异交结实率的重要因素之一,选育开颖性状好的不育系对提高杂交小麦制种产量具有重要意义。

9份具源511S背景的早稻两用不育系主要农艺、品质性状和异交特性研究

为探明以源511S为背景改良的9个水稻两用核不育系的潜在应用价值,调查了改良不育系的主要农艺性状、异交特性、稻瘟病抗性和外观品质性状。结果表明,改良不育系的株型紧凑度、分蘖能力、每穗颖花数、上3叶长度和宽度等植株形态性状基本保持了源511S的特征,部分株系在某些性状上有所改良。9个水稻两用核不育系作早稻种植的播始历期分别为83~92 d,其中8个较源511S短0~6 d;改良不育系在开颖历期、颖尖距和开颖角度等性状上变异方向各异,柱头总外露率均低于背景亲本源511S,异交结实率均在53%以上,其中21YSF21和22SF01异交结实率显著高于源511S;改良不育系稻瘟病苗瘟感病级别为1.1~4.8,其中7个达到中抗或抗性水平;改良不育系的稻谷长宽比和糙米长宽比分别为4.2~5.1和3.6~4.2,均显著大于源511S,垩白粒率和垩白度均明显小于源511S,其中3份不育系垩白度≤3.0。综合分析,21YSF10、21YSF21、22SF15和22SF16生育期较短,株型理想,异交特性较好,稻瘟病抗性中抗以上,稻米垩白度均在5%以下,有望为优质杂交早稻组合配制提供新的不育系资源。

光温敏核不育水稻异交结实潜力的研究

异交结实潜力是指不育系在保证有充足外源花粉供应的条件下的最高结实率 .本研究表明 ,不同的水稻光温敏核不育系具有不同的异交结实潜力 ,异交结实潜力的高低受遗传、环境及遗传与环境互作的共同影响 ;环境对不育系异交结实潜力影响的主因是温度 ,其作用的敏感时期是异交籽粒灌浆充实的前期 ;

水稻6个异交相关性状的SSR关联分析

从水稻核心种质和栽培品种中选取95个品种构成品种总群体,调查该群体6个异交相关性状。选用分布在水稻12条染色体上的93个SSR标记对这95个品种进行基因型鉴定。采用TASSEL软件中一般线性模型对标记与性状间的关联进行分析,发掘有利等位变异和相应载体品种。结果表明:品种总群体中6个异交性状的变异系数为9.9%～62.9%。共检测到22个与异交性状相关联的SSR分子标记,其中8个与剑叶角度相关联,2个与花丝长度相关联,4个与花药长度相关联,1个与柱头长度相关联,3个与柱头外露率相关联,9个与开颖角度相关联。发掘了一批携有优良等位变异且效应值较大的载体品种。携有RM480-197 bp和RM535-170 bp条带的‘无芒早稻’分别对增加剑叶角度和花丝长度效应最大。携有RM311-162bp条带的‘敲冰黄’对增加花药长度效应最大。携有RM498-187 bp条带的‘滇屯502选早’对增加柱头长度效应最大。携有RM206-150 bp条带的‘徐稻5号’对提高柱头外露率效应最大。携有RM311-159 bp条带的‘小白野稻’对增加开颖角度效应最大。这些有利等位变异及其载体品种可用作水稻异交性状遗传改良的亲本。

刺五加、短梗五加的开花动态及繁育系统的比较研究

野外定位观测刺五加 ( Eleutherococcussenticosus)、短梗五加 ( E.sessiliflorus)的开花进程、花朵的功能形态特征和开花动态 ,用杂交指数 ( OCI)、花粉 -胚珠比 ( P/ O)、去雄、套袋、人工授粉等方法分别测定刺五加、短梗五加的繁育系统。结果显示 ,刺五加种群、短梗五加种群的花期均持续 1个月左右 ,刺五加比短梗五加早开花 2 0 d左右 ,二者均有雄蕊先熟现象 ;刺五加是单全异株植物 ,种群内既具有雄株、又具有雌株、还具有两性株 ,繁育系统主要为异交 ,需要传粉者活动才能完成授粉过程。与刺五加不同 ,短梗五加仅具两性花 ,但繁育系统也以异交为主。短梗五加两性花中的雌、雄器官既在空间上分离、又在时间上分离 ,只能进行同株异花间或异株、异花间传粉才能受精结实。

马尾松二代无性系种子园遗传多样性和交配系统分析

运用12对SSR引物,对马尾松二代无性系种子园内61个亲本及其中8个无性系单株的320个子代进行研究。结果显示:子代群体包含亲本群体的所有等位基因,子代与亲本具有同样高的遗传多样性,子代群体的F为0.045,纯合子过剩的现象不明显;树冠北面子代遗传多样性并未因其雌、雄球花量较树冠南面减少而有明显的降低;雌雄均衡和偏雌型植株子代遗传多样性基本一致,以偏雌型植株子代略大,二者F趋于0,子代基本符合哈温平衡。种子园异交率较高,多位点异交率为1.098,子代亲本的近交现象不显著(tm-ts=-0.033);树冠南面多位点与单位点异交率均高于树冠北面;偏雌与雌雄均衡型植株的多位点异交率基本相当,雌雄均衡型植株并未因其雌、雄球花量比例较偏雌型植株减小而呈现异交率明显降低的现象,2种类型植株的近交指数均接近于0。整体而言,马尾松二代种子园子代仍具有丰富的遗传多样性,无性系间基因交流相对充分,子代亲本近交现象不明显。

草乌传粉过程中的广告效应与回报物质研究

虫媒传粉植物与其传粉者之间的相互作用被认为是被子植物花多样性的一个重要选择压力。这种相互作用体现在植物对传粉者的吸引以及传粉者行为对花粉的转运两个方面。本项研究通过去除不同的花部器官研究了草乌(Aconitum kusnezoffii)对其传粉者的吸引,并结合传粉者的访问行为和草乌花的生物学特性探讨了传粉过程与交配系统的适应。红光熊蜂(Bombus ignites)是草乌的有效传粉者。去除花萼片显著降低了红光熊蜂的访问频率,但去除特化成蜜腺叶的花瓣并没有显著改变红光熊蜂的访问频率,这表明草乌吸引红光熊蜂的主要结构是由5枚萼片组成的花部外观形态,而非花瓣。花蜜是草乌提供给红光熊蜂的回报物质,糖浓度为39.23%,组氨酸浓度为0.25μg/μL。草乌花较大、单花花期长、雌雄异熟、花粉寿命长,是一个自交亲和但需传粉者传粉完成繁殖过程的异交物种。草乌花序是无限花序,当上部的花处于雄性阶段时,下部的花正好处于雌性阶段。而红光熊蜂在草乌花序上的访问顺序通常自下而上,带来异交花粉为下部的花进行异花授精,同时又带走上部花的花粉,这就很好地促进了草乌的异交。草乌雄蕊自外向内逐渐成熟,是一种有效的限制传粉者单次访问浪费大量花粉的花粉装配策略,能提高植物通过花粉散布获得的雄性适合度。