花生重组近交系群体的遗传变异与高油种质的创新

花生是世界上食用植物油脂的重要来源之一, 提高含油量是花生育种的重要目标。以不同遗传背景的亲本远杂9102与中花5号杂交构建的花生重组近交系(recombined inbreed lines, RIL)群体, 进行含油量的系统测试和DNA多样性分析。结果表明, RIL群体家系的含油量范围(50.85%~62.11%)大于两个亲本的差异, 最高含油量家系比高油亲本中花5号高5个百分点以上。通过SSR技术分析RIL群体的DNA多样性, 发现家系间存在较大的遗传变异, 杂交重组产生的超亲高油种质分布在不同类群中, 含油量高低与荚果大小和青枯病抗性无明显连锁关系。鉴定获得了3组SSR遗传距离为0、含油量和主要农艺性状相似但青枯病抗性不同的家系。农艺性状和抗病性等鉴定试验筛选出了3份含油量高、农艺性状优良、高抗青枯病的新种质并已进入品种比较试验。     

利用RIL群体创造抗黄曲霉兼抗青枯病的高油花生新种质

协同提高抗青枯病花生品种的黄曲霉抗性及含油量是我国花生育种的重要目标之一。利用远杂9102×中花5号杂交后代衍生的重组近交系群体(RIL),通过黄曲霉抗性、青枯病抗性鉴定及含油量测试,表明黄曲霉抗性受2对连锁并具累加作用主基因+加性多基因控制,含油量受2对具抑制作用主基因+加性多基因控制,RIL群体的黄曲霉抗性和含油量变异远远超过双亲的差异,表明它们均具有通过互补产生超亲性状的潜力。获得了抗黄曲霉或抗青枯病的高油后代家系18份,其中抗黄曲霉兼抗青枯病高油新种质1份(J091)。农艺性状和SSR分析结果表明,18份后代材料具丰富的遗传多样性,农艺性状优良,具有重要育种价值。     

基于SSR标记的马铃薯种质遗传多样性及群体结构分析

明确鉴定种质材料间的群体遗传结构及遗传多样性对构建核心种质库、准确筛选杂交亲本具有重要作用。本研究利用分子标记和农艺性状相结合的方法初步分析了收集保存的62份马铃薯资源的遗传多样性和群体结构。结果表明,参试种质的8个农艺性状的变异系数介于9.50%～52.90%。农艺性状聚类分析表明,在欧氏距离19.0处62份供试材料被分为3个类群,其中类群Ⅰ中包含的材料最多,约占供试材料的96.8%,该结果从特定农艺性状方面较好地揭示了马铃薯种质资源间的表型差异。应用均匀分布在12条染色体上的13对SSR引物从分子水平进一步探究了参试材料的群体遗传结构。Structure软件分析表明,供试材料被划分为3个群体,不同群体间的界限较为明显,PopⅠ亚群和PopⅡ亚群中各材料的遗传背景较单一,PopⅢ亚群具有混合来源,遗传背景较复杂。NTSYS软件计算结果表明,62份马铃薯种质间的遗传相似性系数介于0.50～1.00,SSR标记聚类分析将62份马铃薯种质总体分为3个大群,类群Ⅰ所包括的马铃薯材料占总数的11.3%,类群Ⅱ占17.7%,类群Ⅲ占供试材料的71%。总体来看,农艺性状聚类与SSR分子标记聚类结果相似。本研究对马铃薯进行了综合分析农艺性状与SSR分子标记,有助于准确评价马铃薯种质遗传背景。     

新疆早熟陆地棉种质资源遗传多样性及纤维品质性状SSR关联分析

【目的】探究新疆早熟陆地棉种质资源遗传多样性,发掘特异种质资源和与纤维品质相关的优异等位变异。【方法】以219份新疆早熟陆地棉种质资源为材料,在3个环境下对此群体的15个农艺性状进行鉴定,用128对简单序列重复(Simple sequence repeat,SSR)引物对该群体进行基因型鉴定,使用NTsys-pc2.1进行遗传多样性分析,用Structure 2.3.1和Tassel 5.0对此群体纤维品质性状进行关联分析,依据表型效应值挖掘携带优异等位变异的典型材料。【结果】128对标记在219份资源材料群体中共扩增出244个位点,平均每个标记扩增出1.91个位点;多态信息含量范围为0.13～0.86,平均为0.63;此群体材料间遗传相似性系数分布范围为0.42～0.99,平均为0.61,遗传相似系数在0.5～0.7的占90.19%。通过关联分析检测到11个与纤维品质性状显著关联的标记(P0.01),发掘出7个携带特异等位变异的典型材料。【结论】219份新疆早熟陆地棉种质资源遗传多样性低,基于SSR关联分析发掘了一些与纤维品质性状相关的优异等位变异及典型材料。     

花生SSR标记与农艺性状的相关性

以农家品种四粒红和冀农黑3号构建的包含有251个家系的重组自交系(RIL)群体为材料, 在保定市和邯郸大名县两地进行表型鉴定, 利用Pearson’s相关和逐步多元回归分析了花生农艺性状之间及其与标记的相关性。结果表明, 多数农艺性状间存在显著或极显著相关, 其中相关性最高的为单株生产力和单株仁重(r=0.970), 其次是主茎高和第一侧枝长(r=0.918); 77对SSR标记与18个农艺性状显著相关, 每个性状相关标记数在2~16之间; 14个SSR标记与13个农艺性状关联, 解释的表型变异为5.2%~11.5%。以上结果为今后花生的常规育种和分子标记辅助选择奠定了基础。     

黄麻核心种质的遴选

遴选黄麻核心种质可为黄麻种质创新及新品种选育奠定基础。本研究以300份黄麻种质资源为基础,基于SSR分子标记和农艺性状考察,结合地理来源构建核心种质。结果表明,11个农艺性状变异系数变幅在13.06%～84.87%,表现出丰富的遗传多样性。按农艺性状聚类分析可划分为8个类群,按分子标记聚类可划分为10个类群。结合2个聚类分析、地理位置并按比例取样,建立一个由108份品种(系)组成的预选核心种质。采用44对SSR引物对其进行遗传差异分析,在遗传相似系数为0.65时,可把108份品种(系)分成圆果种和长果种两大类。根据遗传差异分析,剔除遗传相似系数大于或等于0.85的遗传冗余,获得84份品种(系)的核心种质,其中圆果种60份和长果种24份。比较84份核心种质与300份种质的农艺性状变异系数及Shannon-Wiener指数发现,两者之间相差不大,表明遴选的84份核心种质可以最大限度代表300份黄麻种质资源的遗传多样性加以利用和保存。     

利用配合力和SSR标记对玉米Tuxpeno种质遗传潜势的研究

采用NCⅡ遗传交配设计,以Tuxpeno种质选系和测验种10份玉米自交系为材料,组配了25个杂交组合,田间组合多点鉴定,对产量、株高和穗位高等10个农艺性状进行配合力分析,同时,利用SSR标记分析了10份自交系的遗传变异参数.结果表明:调查的10个农艺性状在组合间方差均达到显著水平.行粒数、百粒重、秃尖长、出籽率、穗位高和小区产量在地点与组合互作间方差分析均达到了极显著水平.SSR标记结果表明:筛选出25对多态性较高且带型稳定、清晰的SSR引物,在10个供试材料中共检测出127个等位基因变并,每对引物检测出2～10个等位基因,平均每个位点检测到的等位基因数为5.08个;10份自交系之间遗传距离范围是0.4157～0.9722,遗传距离以0.70为标准,分为2类群;基于配合力和微卫星(SSR)标记的遗传潜势数据的评估,计算分子标记遗传距离与两点联合产量的相关系数仅为0.07.在本研究中,Tuxpeno种质与78599和Reid种质可能组配成较大潜力的杂种优势模式.通过对Tuxpeno种质杂种优势的系统研究,可以为更好利用Tuxpeno种质为桥梁,实现Tuxpeno种质在温带玉米育种中的快速、有效利用提供一个可供选择的潜在模式和参考依据.     

大豆重组自交系Jinf的构建及主要农艺性状和SSR基因型分析

本研究以晋豆23为母本，灰布支黑豆为父本，用“单粒混传”法构建了一个含有474个家系的F10代的大豆重组自交系Jinf。2002年本研究组对F8代RIL群体Jinf进行生育期、形态性状、产量构成及抗逆性等29个性状进行了观察记载和统计分析研究。所有观察性状在RIL群体Jinf中均表现有较大的变异范围，绝大部分性状呈连续变异、正态分布，且存在双向超亲分离现象，表明这些观察性状大都为数量性状由多基因控制。从表型分析初步认为各家系内部趋于纯合。本研究进一步选取了能覆盖大豆基因组的355对SSR引物对RIL群体Jinf进行SSR分析，212对SSR在亲本中表现有多态性，多态率为59．72％。212对引物获得213个座位用来评估大豆群体的遗传结构，各座位在群体中的多态性指数趋向于0．5，在0．375—0．500范围内波动。160个SSR座位(75．12％)在群体中呈1：1的分离比，53个SSR座位(24．88％)在群体中偏分离，SSR座位的杂异率在0—9．32％之间。分析还表明111个家系(94．07％)趋于纯合，其中31个家系(26．27％)完全纯合，而有7个家系的杂合率在15．31—42．72％之间。分析表明大豆RIL群体Jinf的各个家系的基因型组成父本灰布支的贡献率为51％，初步表明双亲对子代的遗传贡献基本上是平衡的。偏斜度(Skewness=-0．1052)与峰值(Kutosis=0．1597)及X^2检验表明群体的基因型组成分布呈正态分布。本研究初步认为，大豆RIL群体Jinf是一个遗传结构合理，适合于大豆遗传作图、基因定位等基因组研究和育种应用的RIL群体。     

玉米温-热种质杂交后代选系遗传结构的SSR标记分析

利用SSR标记技术,对温热种质5003×A19杂交F6、F7后代性状基本稳定的22个选系遗传结构（变异）进行了初步研究。从88对SSR引物中,筛选出48对表现多态性丰富、带型清晰明显且稳定的引物,分析了22个选系的遗传多样性及遗传结构,并对其应用前景进行了探讨。根据SSR标记结果,用UPGMA法进行聚类分析表明,双亲及其杂交后代全部选系与标准测验种478、B73属于同一个杂种优势群-PA群,玉米温热种质杂交后代选系虽然出现了丰富的遗传变异,但在类群划分上仍然保持双亲的基本类群特征。从基于SSR分子标记的各选系遗传组成分析,温带种质（5003）遗传背景明显高于热带种质（A19）,在各选系中温带种质5003遗传背景平均含量为64.03%、A19遗传背景平均含量为30.03%、非双亲遗传背景平均含量为5.94%;SSR标记分析显示,在温-热带种质杂交后代的多数选系中均出现新的等位基因,且通过多代选择仍是有效的,说明温热种质杂交群体有广泛的遗传变异基础,是玉米种质扩增、改良的有效途径。     

抗青枯病兼大果和高出仁率的花生新种质创制

青枯病是影响花生产量和品质的重要土传性细菌病害,百果重和出仁率是与花生产量相关的重要性状。本研究利用远杂9102和徐州68-4杂交构建的RIL群体,在B02染色体上定位到青枯病抗性主效QTL qBWRB02。结合前期对百果重和出仁率QTL的定位结果发现,所涉及的3个性状的主效QTL分布在不同的染色体上。以RIL群体基因型数据和多个环境的青枯病抗性、百果重和出仁率表型数据为基础,利用与主效QTL紧密连锁分子标记筛选出6份聚合抗青枯病、荚果大、出仁率高3种优良性状的新种质,可以作为育种中间材料或亲本培育高产抗病新品种。本研究利用分子标记辅助选择和表型鉴定相结合有效筛选抗病高产种质,为未来花生育种提供了新思路。     

陆地棉重组近交系“中G6” QTL的初步定位

 利用2个陆地棉种质材料爱字棉1517与德州047构建了重组近交系。田间调查显示,两亲本田间性状差异多数达到显著或极显著,群体性状数据完全符合受多位点控制的数量性状遗传的特征。分子标记多态性筛选结果表明,两亲本亲缘关系相对较近,利用SSR构建高密度遗传连锁图有一定困难,但对于所定位的QTL位点,其准确性将会有一定程度提高。试验构建了一张包括51个标记分为15个连锁群的遗传连锁图,总长504.05 cM,覆盖棉花基因组总长度的10.08%。利用两年田间数据检测到QTL位点15个,其中生育期性状3个,纤维品质性状7个,产量性状5个。与标记图距在1 cM以内的QTL位点7个,这将对分子标记辅助育种具有一定的参考价值。     

Comparative performance of diploid and tetraploid progenies from 2x.2x crosses in potato

Summary Selection criteria for agronomic characters in a potato breeding program at the diploid (2x) level may differ from selection criteria used when selecting breeding lines at the tetraploid (4x) level. Differences between selection criteria are expected, (1) when expression of the characters is different at both ploidy levels and/or (2) when the effect of diploid breeding lines on agronomic characters of tetraploid progenies is different from the effect of tetraploid breeding lines. In this investigation sets of diploid and tetraploid progenies, each set derived from the same 2x.2x cross, were compared as to the expression of six agronomic characters. Diploid progenies had significantly lower yields (due to smaller tubers) and significantly higher under water weights than tetraploid progenies. Vine maturity and chip colour were similarly expressed at both ploidy levels. Correlations between yield and yield components, and between under water weight and chip colour were similar at both ploidy levels. The lower yields and higher under water weights found in diploids point to the need of different selection criteria for selecting diploid and tetraploid breeding lines.     

Comparison of QTLs mapped in RILs and their test-cross progenies of tropical maize for insect resistance and agronomic traits

Quantitative trait loci (QTL) affecting resistance to south-western corn borer Diatraea grandiosella (SWCB) and sugarcane borer Diatraea saccharalis (SCB) have been identified previously in F_2:3 lines and recombinant inbred lines (RILs) of tropical maize using restriction fragment length polymorphism (RFLP) analyses. Our objective was to determine whether QTLs identified in these generations are also expressed in test crosses (TC) of RILs. A population of 166 TC progenies was developed by crossing RILs from the cross CML131 (susceptible) × CML67 (resistant) with the unrelated, susceptible tester line CML216. Resistance to first-generation SWCB, measured as leaf-feeding damage (LFD) under artificial infestation, and other agronomic traits were evaluated in two environments for the TC progenies and three environments for 183 RILs. The correlation between line per se and TC performance was low for LFD and intermediate for most agronomic traits. Estimates of the genotypic variance and heritabilities were smaller in the TC progenies than in the RILs for all traits. Quantitative trait loci were identified using an RFLP linkage map with 136 loci. For LFD, four QTLs were detected in the TC progenies, of which two were in common with nine QTLs previously mapped in the RILs. Few QTLs for agronomic traits were common to the two types of progeny, because of the low consistency of QTL positions for all traits in RIL and TC progenies, the use of TC progenies should be considered in QTL mapping studies as the first step for marker-assisted selection in hybrid breeding.     

棉花IF2群体构建及其在纤维品质遗传和杂种优势研究中的应用

以陆地棉重组自交系RIL为材料,采用RIL系间随机交配的方式构建了一个含有188个组合的IF₂群体。对该群体的棉花纤维品质性状表现进行了评价,并采用A、D遗传模型对其纤维品质性状的遗传效应和杂种优势进行了分析。结果表明,陆地棉IF₂群体中5个纤维品质性状均呈现良好的正态分布,且各性状的表型平均值大多与F₁杂交种相近,具有明显的杂种优势。显性与环境的互作效应是控制棉花纤维品质遗传的主要因素,其次是基因的加性效应,环境因素对于棉花纤维品质的杂种优势表现巨大的影响,两个环境中预测到的杂种优势值具有明显的差异。IF₂群体是棉花数量性状遗传和杂种优势预测的优良研究群体。     

Phenotypic diversity and relationships of fruit quality traits in peach and nectarine [<Emphasis Type="Italic">Prunus persica</Emphasis> (L.) Batsch] breeding progenies

Agronomic and fruit quality traits were evaluated and compared for three consecutive years on 1,111 seedlings coming from 15 peach and nectarine breeding crosses, grown under a Mediterranean climate. Significant differences among and within the different progenies were found for most of the traits analyzed. The breeding population segregated for several Mendelian characters such as peach or nectarine fruit, round or flat fruit, yellow or white flesh and freestone or clingstone. In addition, aborting fruit and flat fruit trees were found in our progeny, and our data seem to support multi-allelic control of both flat shape and aborting fruit. The variation within the progenies of some traits such as blooming and harvesting date, yield, fruit weight and SSC was continuous, suggesting a polygenic inheritance. Relationships between qualitative pomological traits and these agronomic and fruit quality parameters were also found. Valuable correlations among agronomic and fruit quality parameters were found, although coefficients of variation depending on the progeny should be considered. In addition, principal component analysis (PCA) revealed several relationships among quality traits in the evaluated progenies. Based on this evaluation, 26 outstanding genotypes were pre-selected from the initial breeding population for further studies.     

Genetic variation, heritability and progeny testing in meadow bromegrass

Meadow bromegrass is a recently introduced pasture grass in western Canada. Its leafy production and rapid regrowth have made it a major grass species for pasturing beef animals in this region. Because relatively little breeding work has been done on this species, there is little information on its breeding behaviour. The main objective of this study was to estimate genetic parameters and assess breeding methodologies for meadow bromegrass. Forty half‐sib (polycross and open‐pollinated) and full‐sib (selfed) progenies were evaluated for dry matter and seed yield, fertility index, harvest index, plant height, plant spread, crude protein, neutral detergent fibre and acid detergent fibre. Genetic variation for seed yield, harvest index, and plant height was significant in the open‐pollinated and selfed tests. Genetic variation estimates for dry matter yield were negative (polycross), not significant (open‐pollinated), or significant (selfed). Estimates of genetic variation for quality traits were not significant, except for acid detergent fibre (selfed). Correlations among characters indicated that it is possible to simultaneously improve seed and forage yield. Rankings of progenies by the half‐sib tests for forage and seed yield were not altered by the use of the synthetic parental value (SV_i), which includes information from selfed progeny. The polycross progeny test did not discriminate parents as well as the open‐pollinated and selfed tests; this may have been a result of non‐random pollination in the polycross. Correlation among the progeny tests, showed that open‐pollinated and selfed progeny tests agreed for all characters, except for harvest index, while correlation between polycross and selfed tests were significant for six characters but not dry matter yield, and acid and neutral detergent fibres. The most dissimilar tests were polycross and open‐pollinated, with significant correlations found only for fertility index, height, spread and neutral detergent fibre. It was concluded that there was significant variation and moderate heritability for most traits in the meadow bromegrass populations evaluated, and that the open‐pollinated progeny test is the method of choice for selecting parents for synthetics of this species.     

Population-specific QTLs and their different epistatic interactions for pod dehiscence in soybean [<Emphasis Type="Italic">Glycine max</Emphasis> (L.) Merr.]

Pod dehiscence (PD) prior to harvest results in serious yield loss in soybean. Two linkage maps with simple sequence repeat (SSR) markers were independently constructed using recombinant inbred lines (RILs) developed from Keunolkong (pod-dehiscent) × Sinpaldalkong (pod-indehiscent) and Keunolkong × Iksan 10 (pod-indehiscent). These soybean RIL populations were used to identify quantitative trait loci (QTLs) conditioning resistance to PD. While a single major QTL on linkage group (LG) J explained 46% of phenotypic variation in PD in the Keunolkong × Sinpaldalkong population with four minor QTLs, three minor QTLs were identified in the Keunolkong × Iksan 10 population. Although these two populations share the pod dehiscent parent, no common QTL has been identified. In addition, epistatic interactions among three marker loci partially explained phenotypic variation in PD in both populations. The result of this study indicates that different breeding strategies will be required for PD depending on genetic background.     

Quantitative trait loci mapping of forage agronomic traits in six mapping populations derived from European elite maize germplasm

Four agronomic traits were analysed including dry matter concentration (DMC) and dry matter yield (DMY) for stover, plant height (PHT) and days from planting to silking (DPS). We mapped quantitative trait loci (QTL) in three populations with doubled haploid lines (DHL), one RIL population and two testcross (TC) populations derived from crosses between two of the four populations mentioned above to elite tester lines, based on field phenotyping at multiple locations and years for each; 146–168 SSRs were used for genotyping of the four mapping populations. Significant high phenotypic and genotypic correlations were found for all traits at two locations, while DMC was negatively correlated with the other traits. A total of 42, 41, 54, and 45 QTL were identified for DMC, DMY, PHT, and DPS, respectively, with 9, 7, 12, and 7 major QTL for each trait. Most detected QTL displayed significant interactions with environment. Major QTL detected in more than two populations will contribute to marker‐assisted breeding and also to fine mapping candidate genes associated with maize agronomic traits.     

12个玉米群体的主要农艺性状与产量、品质的灰色关联度分析

为了明确玉米群体主要农艺性状与产量、营养品质的关系,应用灰色关联度分析方法对12个玉米群体的主要农艺性状、产量、营养品质等进行了灰色关联度分析。结果表明:与产量密切相关的农艺性状是出籽率、行粒数、穗粗、百粒质量、株高等;与粗蛋白、粗脂肪、粗淀粉和赖氨酸含量等营养品质密切相关的农艺性状是穗粒数、百粒质量、行粒数、出籽率、穗行数等。根据玉米群体主要农艺性状间的灰色关联度关系,说明在玉米群体产量、营养品质改良的过程中,在保证适当株高的前提下,要注重选育出籽率、百粒质量较高品种,同时不要忽略对玉米群体穗行数、行粒数、穗粗的选择,为选育高产、优质玉米新品种提供科学依据。