Traits related to drought resistance in common bean

Common bean (Phaseolus vulgaris L.) is grown in regions where water deficits during reproductive development significantly reduce yield. The purpose of this study was to evaluate the association of specific phenological and physiological traits with drought resistance in common bean. Five genotypes were grown under and near a rain shelter in 1988, and an additional 16 progeny lines were included in 1990. Drought stress determined by the drought intensity index was severe (0.78) in 1988 and more moderate (0.63) in 1990. Water stress reduced the expression of most traits with the exception of days to flower and leaf moisture retention capacity. Seed yield among genotypes was reduced from 22 to 71% due to drought. Yield under stress was correlated with yield under nonstress in 1990 and negatively correlated with the drought susceptibility index in 1988. Yield components which exhibited the largest differential genotypic responses to stress were pod and seed number, whereas seed size was more stable. Genotypic variation was detected in all the partitioning indexes, chiefly harvest index and relative sink strength, and the heritability estimates for these traits were high. The limited genetic variability observed among water relations traits and their role in water conservation would restrict their potential use in the selection for drought resistance in common bean. The differential correlations between phenological, biomass and partitioning traits and the indexes for yield and drought susceptibility would suggest that the most effective approach in breeding for drought resistance in common bean would be based first on selection for high geometric yield followed by selection among the high-yielding individuals for low to moderate levels of the drought susceptibility index. This revised version was published online in July 2006 with corrections to the Cover Date.     

Genetic variation of yellow-seeded rapeseed lines (Brassica napus L.) from different genetic sources

In order to breed yellow-seeded rapeseed, 16 yellow-seeded lines of Brassica napus L. derived from eight genetic sources were used. The genetic variation of the seedcoat ratio, the cellulose content of the seedcoat, the oil content of the seedcoat and of the embryo, and also the correlations between these characters of the yellow- and brown-seeded plants from the same line, were analysed by variance analysis and path analysis. The results show that the seedcoat ratio and cellulose content of brown seeds are 4.2% and 17.74%, respectively, higher than that of yellow seeds and the oil content of the seedcoat of brown seeds is 3% lower than that of the yellow seeds, these differences all being highly significant. However, the differences between yellow and brown seeds in 1000-seed weight and oil content of the embryo were very small. Both characters are determined mainly by the genetic background and not by seed colour or seedcoat thickness. The correlation analysis revealed that the seedcoat thickness has a highly significant positive correlation with the cellulose content of the seedcoat and is highly significantly negatively correlated with the seedcoat oil content and the 1000-seed weight. The oil content of the embryo alone has a highly significant negative correlation with 1000-seed weight. In yellow seeds, the seedcoat thickness has a large and directly positive effect on the oil content of the embryo whereas the 1000-seed weight has a negative one; the opposite was found in brown seeds. Selection objectives in breeding yellow seeds in Brassica napus are also discussed.     

甘蓝型油菜GPDH基因克隆及其生物信息学分析

为了进一步研究甘蓝型油菜GPDH基因,通过从拟南芥GPDH基因与甘蓝型油菜的共线性分析发现:拟南芥GPDH基因(At2g41540)在甘蓝型油菜A基因组和C基因组中有4个拷贝,分别为:GSBRNA2T00132785001、GSBRNA2T00024258001、GSBRNA2T00058395001、GSBRNA2T00019118001。从Gen Bank分别下载了它们的DNA序列和c DNA序列,c DNA序列依次命名为GPDH1、GPDH2、GPDH3、GPDH4。根据序列信息设计了4对不同的引物,从甘蓝型油菜湘油15号c DNA全长序列中扩增出了4条片段,分别命名为Bn GPDH1、Bn GPDH2、Bn GPDH3、Bn GPDH4。利用生物信息学软件和在线系统进行核苷酸序列分析和蛋白进化分析。结果显示:4条片段大小依次为1 395,1 395,1 389,1 536 bp。其中,Bn GPDH4翻译成氨基酸时序列中间出现终止密码子,不能合成有效蛋白。3个Bn GPDH蛋白的氨基酸数目为464,464和462个,理论分子量为51.584 4~51.829 7 k Da,二级结构α螺旋和无规则卷曲所占比例在42%左右,其次是延伸链所占比例约为15%。三者的跨膜结构总体来说是相同的。3个蛋白都由保守结构Gps A、NADB_Rossmann superfamily和NAD_Gly3P_dh_C superfamily组成,属于GPDH超基因家族。同源建模分析表明3个蛋白均能适用甘油3磷酸脱氢酶(Glycerol-3-phosphate dehydrogenase,GPDH)模型。对其进行亚细胞定位预测在细胞质膜的概率为79.0%。从序列分析、核苷酸聚类、理化性质预测、二级、三级结构预测、亚细胞定位预测、氨基酸聚类分析得出结论,它们具有GPDH基因家族的特征,为甘蓝型油菜GPDH基因家族中的成员。     

甘蓝型油菜早熟性状QTL定位及候选基因筛选

目前对于油菜早熟的研究主要围绕开花期性状进行,虽然开花期与生育期呈显著正相关,但却并不完全一致。对于油菜开花后一系列生长发育进程相关性状的遗传研究和QTL定位鲜有报道。本研究以成熟期差异较大的2个油菜品种‘花前早’和‘Global’构建的DH群体为材料,对影响油菜全生育期的各个发育阶段(开花期、花期持续时间、角果期持续时间和全生育期等)进行表型调查和QTL定位分析。共检测到30个早熟相关性状QTL位点,其中开花期、花期持续时间、角果期持续时间和全生育期等分别检测到12、5、4和9个QTL位点,解释了5.8%~22.4%的表型方差。发现4、2和1个全生育期QTL置信区间分别与开花期、花期持续时间、角果期持续时间位点置信区间完全或部分重叠。筛选到29个可能与油菜早熟性状相关的候选基因,它们通过调控花期或籽粒发育等生长发育进程影响油菜早熟。因此,在早熟性状的研究中,可以同时从开花期和籽粒发育过程入手,不但有利于使熟期进一步提前,也可减缓早熟油菜品种过早开花导致的冬前低温寒潮天气的不利影响。     

甘蓝型油菜千粒重全基因组关联分析

千粒重是油菜产量构成的重要因素之一。本研究利用高通量SNP芯片对496份具有代表性的油菜种质资源进行基因型分析,考察群体在3个环境(14NJ、15TZ、16TZ)中的千粒重表型,利用混合线性模型(mixed linear model,MLM)和一般线性模型(general linear model,GLM)进行全基因组关联分析。结果表明,本群体在3个环境中千粒重的广义遗传力为63.12%。MLM模型检测到6个显著位点,解释28.92%的表型变异;GLM模型检测到61个显著位点,解释47.08%的表型变异。合并共同位点后得到62个显著位点,联合解释47.31%的表型变异。这些位点分布在基因组所有染色体上,在A07、A03和C06染色体上分别检测到数目最多的9、8和7个位点。其中效应最大的位点Bn-scaff_17526_1-p1066214位于C09染色体,在MLM和GLM模型中表型贡献值分别为5.55%和15.26%。21个位点与前人报道的QTL重叠,其中8个位点得到至少2个群体的验证。其余41个位点为新鉴定的位点,其中多个位点效应高且在多环境中被检测到,如位点Bn-A03-p560769、Bn-scaff_15743_1-p599416和Bn-scaff_15743_1-p590955等。在11个位点附近找到DGAT、EOD3、AGL61、WRI1、DA2、RAV1等拟南芥已报道千粒重基因的同源基因。本研究结果有助于解析甘蓝型油菜千粒重的遗传基础,为研究千粒重的调控机制、指导千粒重的遗传改良奠定基础。     

人工合成甘蓝型油菜抗旱性及DNA甲基化水平分析

甘蓝型油菜是具有重要经济价值的多倍体物种,是优质食用植物油和饲料蛋白质的重要来源之一。但是其驯化历史较短,遗传背景狭窄,且在整个生命周期中都对干旱胁迫敏感,因此培育高产耐旱品种是甘蓝型油菜的重要育种目标之一。本文用15%PEG-6000模拟干旱胁迫,对人工合成甘蓝型油菜不同世代(S1～S4)及其二倍体亲本进行不同时间的胁迫处理,并结合表型观察,以及叶片中丙二醛(MDA)、可溶性蛋白含量、过氧化物酶(POD)、超氧化物歧化酶(SOD)等生理指标的测定,初步了解上述材料的抗旱性差异。结合表型观察和叶片中相对含水量分析,发现人工合成甘蓝型油菜S1～S4及其亲本的抗旱性表现为甘蓝 Bn-S3 Bn-S4 Bn-S1 Bn-S2白菜型油菜。干旱胁迫后Bn-S3、Bn-S4的POD及SOD活性较高,MDA含量较低,表明Bn-S3和Bn-S4能更加有效地清除活性氧(ROS),对过氧化损伤的防御能力更强。通过HPLC分析发现所有材料的甲基化水平在胁迫12 h时最高,其中亲本白菜型油菜Br的甲基化水平最高, Bn-S1和Bn-S4介于两亲本之间,而Bn-S2和Bn-S3低于两亲本。甲基化敏感多态性分析也显示人工合成甘蓝型油菜在干旱胁迫后,甲基化和去甲基化水平均发生了明显的变化,表明植物的甲基化变化可能有利于提高其抗旱能力。     

甘蓝型油菜杂种优势和过氧化物酶的关系分析

对3个甘蓝型油菜杂交组合和亲本的农艺性状表现及其与过氧化物酶活性的关系进行了浅析,研究结果表明：杂种的产量性状,如单株粒重、单株有效角果数、有效分枝数、主花序有效角果数等,比其双亲有明显的优势;杂种花期的过氧化物酶活性高于双亲,与株高、有效分枝数、有效角果数、千粒重等性状具有显著的相关性;杂种的过氧化物酶同工酶谱表现为双亲的互补型。     

油菜不同产量类型品种氮素吸收与利用特性研究

摘要: 【研究目的】探讨甘蓝型油菜不同产量类型品种氮素吸收与利用特性。【方法】在不同土壤肥力条件下以甘蓝型油菜品种（2006-2007年度73个、2007-2008年度98个）为材料,成熟期测定各器官干物重、氮素含量,采用组内最小平方和动态聚类方法对供试品种产量进行聚类。研究不同产量类型品种氮素积累与分配差异。【结果】结果表明：供试品种间产量差异很大,类型间差异显著。随着产量增加,氮素吸收总量、氮素籽粒生产效率增加,籽粒氮素积累量增加,茎枝、果壳氮素分配比例下降,籽粒氮素比例增加。土壤肥力高,植株吸氮总量增加,氮素籽粒生产效率降低。【结论】增加氮素吸收总量,促进氮素向籽粒中输送,使得高产和高氮素利用效率统一。     

Genetic analysis of rapeseed self-incompatibility lines reveals significant heterosis of different patterns for yield and oil content traits

Self‐incompatibility is one of the most effective approaches to utilizing heterosis in oilseed rape around the world. To evaluate the heterosis of double low self‐incompatibility, the possibility of combining seed yield and oil content, and the genetic effects of parents on their hybrid progenies, a 2‐year field trial using a 3 × 22 NC II mating design was conducted during the 1999‐2001 growing seasons in Wuhan, China. Significant differences in seed yield per plant and seed oil content were observed among the F1 hybrids and between F1 progenies and their parents. However, the heterosis for seed yield per plant was much greater than that for seed oil content. Mid‐parent heterosis and high‐parent heterosis of seed yield per plant ranged from 5.50 to 64.11% and from –2.81 to 46.02%, while those of seed oil content ranged from –1.55 to 7.44% and –3.61 to 6.55%, respectively. Non‐additive genetic effects were a major mechanism that accounted for the yield heterosis in addition to additive effects. In contrast, seed oil content heterosis was mainly dependent on an additive genetic effect. General combining ability (GCA) determined the stability of hybrid cultivars. In hybrid breeding, parental materials might be selected by the sum of GCAs and variances of special combining abilities (SCAs) of female and male parents for traits affected by both additive and non‐additive effects, and by the sum of GCAs of two parents for traits controlled mainly by additive effects. Primary branches and their siliques were the most important yield traits.     

甘蓝型油菜白花突变体的遗传研究和白花胞质雄性不育系的选育

用白花突变体和白花不育突变体分别选育白花品系G95150和白花胞质不育系7600 A。遗传研究表明,白花对黄花由一对不完全显性基因控制。7600A在农艺性状上与其保持系G95150完全一致：叶色浓绿,植株较矮（163.5 cm）、生育期较长（243天）、抗寒能力较差（冻害率100%,冻害指数33.8）。7600A花色纯白、花瓣皱缩、花药小、低温存在微量花粉。G95150和7600 A的芥酸含量为0.8854 %,硫甙含量70.5461μmol/g。     

Geneticanalysis of drought stress response in rapeseed (Brassica campestris and B. Napus). II. Yield improvement and the application of selection indices

Summary The expected improvement in grain yield if selection was made for plant characters measured between flowering and maturity was evaluated in populations of rapeseed (Brassica campestris and B. napus) grown in a droughted environment. Drought was commenced at flowering in each species and measurements were made on plants at the commencement of the drought stress, during the stress treatment and at crop maturity.Substantial genetic and phenotypic variation was observed in yield as well as the different morphophysiological determinants of yield. In B. campestris no single parameter was found to be a suitable alternative selection criterion to yield since the correlated responses in yield if selection was for another character was lower than if selection was for yield alone. By the use of a selection index however, joint selection for yield, as well as harvest index, 1000 seed weight and seeds per pod, was expected to be 20% more effective than direct selection for yield under drought. In the B. napus population direct selection for flowering time or for harvest index was predicted to result in a genetic advance in yield equal to or greater than that obtained by direct selection for yield, whereas joint selection for flowering time and yield should result in a 16% greater yield increase. Selection for increased yield in these populations grown in droughted conditions is discussed.     

甘蓝型油菜花叶性状的遗传及基因定位

为明确甘蓝型油菜花叶性状的遗传特点,开发与花叶性状连锁的分子标记。以甘蓝型油菜品系2205(圆叶)、1423(花叶)为亲本,构建了3个世代群体:F1、BC1和F2,探讨花叶性状的遗传规律;利用分子标记技术对花叶基因进行定位。结果表明,F1植株叶形表现为花叶,BC1(F1×2205)和F2中花叶与圆叶的植株分离比分别符合1∶1和3∶1,说明甘蓝型油菜的花叶性状受1对不完全显性基因控制。利用集团分离法(BSA)筛选637对SSR引物,共筛选到了3个与花叶基因紧密连锁的SSR标记:CB10079、BNGMS114和BNGMS385。连锁分析发现,这3个连锁标记均位于花叶基因的一侧,其中BNGMS114与花叶基因的遗传距离最近,其遗传距离为2.5 c M。将这3个连锁标记的序列与白菜基因组的序列进行比对,结果发现它们与白菜A10染色体的序列共线性较好,花叶基因位于A10染色体的15.70 Mb下游区段。上述标记的获得为油菜花叶性状的分子标记辅助选择育种以及花叶基因的克隆奠定理论基础。     

Improvement of Sclerotinia resistance of a Polima CMS restorer line of rapeseed via phenotypic selection, marker-assisted background selection and microspore culture

Sclerotinia stem rot caused by Sclerotinia sclerotiorum is one of the most severe diseases of rapeseed in China and other major growing regions. The objective of this study was to improve the S. sclerotiorum resistance of 'Hui5200', an elite 'Polima' CMS restorer line, by introgression and fixation of resistance alleles from the partially resistant cultivar 'NingRS-1' via phenotypic selection (PS), marker-assisted background selection (MAB) and microspore culture. A progeny designated as 'RSH' with greatly improved Sclerotinia resistance and a similar genetic background as 'Hui5200' was obtained by two backcrosses and one selfing. From a selected elite progeny line (named as 7-5) double haploid (DH) lines were developed. By three cycles of PS considering economic traits and genetic distance analysis, four resistant DH restorer lines with elite economic traits were finally selected. The obtained resistant restorer lines have been used to produce commercial F₁ hybrids. The results indicated that backcrossing plus PS and MAB is effective and suitable for improving resistance of rapeseed to S. sclerotiorum .     

陆海BC4F3和BC4F4代主要农艺性状的相关和通径分析

为了更有效地对棉花农艺性状进行选择,缩短选择育种的年限,通过采用相关、偏相关、通径以及回归分析的方法,研究了陆海高代回交自交后代BC4F3和BC4F4群体的6个农艺性状间的关系。结果表明：铃重、衣分、铃数、果枝数、株高与单株皮棉产量呈极显著正相关,其中铃数是决定单株皮棉产量最主要的因素,在BC4F3和BC4F4代对单株皮棉产量的直接通径系数分别为0.6650、0.6689,其次是铃重和衣分,两者的贡献大小相当;果枝数和株高可以通过铃数对单株皮棉产量起较大的正向促进作用;最优回归方程显示,铃重、衣分、铃数和株高对单株皮棉产量有显著的正向影响。本研究明确了棉花产量育种的主攻方向,为提高棉花选择育种效率和实现高产提供理论指导。     

草铵膦胁迫下油菜苗期叶片药害相关性状的全基因组关联分析

随着油菜大面积种植和田间草害的日益严重, 草铵膦近年来被尝试性地用于田间除草, 但草铵膦在杀除杂草的同时或轻或重会对油菜产生药害, 影响其正常生理活动, 甚至影响其产量。本研究通过比较, 选取最能体现油菜苗期耐药性差异的200 mg L^-1作为胁迫浓度。以506份具有代表性的甘蓝型油菜品种(系)为材料, 利用芸薹属60k Illumina Infinium SNP芯片分析其基因型, 对油菜种质苗期的单位叶面积干重耐除草剂系数(CLW)、叶绿素含量耐除草剂系数(CCC)和综合药害指数(CPC)进行全基因组关联分析, 从基因组水平分析油菜在草铵膦胁迫下的生理和形态反应。关联分析中, 扫描到与单位叶面积干重耐除草剂系数显著相关的SNP位点6个, 表型贡献率在6.53%~10.04%之间; 与叶绿素含量耐除草剂系数相关的SNP位点共22个, 表型贡献率在4.97%~6.20%之间; 与综合药害指数相关的SNP位点98个, 覆盖了A、C基因组, 贡献率在3.25%~18.66%之间。通过对显著SNP位点对应的LD区间基因序列的分析, 共获得18个与草铵膦的灭生机制相关的候选基因。在叶绿素含量耐除草剂系数关联位点的LD区域发现11个候选基因, 其中9个参与酰基转移酶活性的调控, 2个与乙酰CoA转移酶活性有关。在与综合药害指数关联位点的LD区域发现7个候选基因, 其中1个与谷氨酰胺转移酶活性有关, 参与谷氨酰胺代谢, 其余6个和乙酰CoA转移酶活性有关。这些基因调控的生理生化过程均与叶片干重、叶绿素含量的变化及草铵膦的灭生机制有关。这些关联位点和候选基因的挖掘, 将为油菜在草铵膦逆境胁迫下的生理生态反应的基因调控机制研究提供参考。     

甘蓝型油菜抗裂角品种(系)的选与分析

利用随机碰撞测试方法,对229份自交纯合的甘蓝型油菜品种（系）进行了抗裂角指数测定,以期筛选出抗裂角种质。结果表明,抗裂角性状在现有品种（系）中存在广泛变异,变异系数达114．4％。发现了2份抗裂角的品种（系）,占0．9％;较抗的资源占3．93％;处于中间状态的品种（系）占8．73％;易裂角资源占27．07％,极易裂角的品种（系）占59．39％。选择6个品种（系）进行了连续3年的测试,表明抗裂角性状由品种（系）的遗传特性决定,但受环境条件影响;随机碰撞法具有较好的重现性。简单相关分析显示,抗裂角指数与角果密度呈显著负相关,与角皮厚度、角果长度、角果宽度、角喙长度、角粒数呈显著正相关,但相关系数都很小。     

RAPDs和RFLPs分析甘蓝型杂交油菜亲本的遗传多样性

利用RAPD和RFLP分子标记技术对甘蓝型杂交油菜亲本遗传多样性的分析结果表明:(1)20个亲本间具有丰富的遗传多样性,40个引物扩增出277条多态性带,其中21条带为10个亲本所特有,12个探针得到了117条多态性杂交带,其中7条带为5个亲本所特有;(2)不育系与恢复系之间的遗传差异大于不育系内和恢复系内的遗传差异;(3)依RAPDs与RFLPs估     

一个甘蓝型油菜细胞质雄性不育相关基因克隆和表达分析

利用甘蓝型油菜与播娘蒿融合杂种中的不育株与甘蓝型油菜杂交、回交,得到细胞质雄性不育系NJ65A。根据pol和nap雄性不育高度相关的基因orf224和orf222设计兼并引物,从NJ65A植株中克隆得到一个长度为675bp的基因,命名为orf224-NJ65A。该基因编码224个氨基酸,氨基酸序列与orf224、orf222和orf220序列相似性分别为：70％、53％、60％。RT—PCR表达分析表明：orf224-NJ65A在所检测的组织中都有表达,但在花、花蕾和茎中的表达量较大。推测orf224-NJ65A与细胞质雄性不育有关。