玉米胚乳突变基因ae1和du1的遗传效应

利用玉米ae1和du1隐性纯和突变自交系与普通玉米自交系48-2的杂交F₁、F₂代子粒为研究材料,通过单粒法测定子粒的直链淀粉含量和重量,用于分析玉米胚乳突变基因ae1和du1的遗传效应。结果表明：F₂代中具有ae1或者du1纯和突变的子粒表皮皱缩,重量明显下降,直链淀粉含量显著提高。在ae1与du1的杂交后代中,子粒的单粒重和直链淀粉含量没有显著变化,表明ae1与du1双突变并不能导致直链淀粉含量增加。单突变的ae1和du1群体内各子粒间的直链淀粉含量和重量差异较大,说明遗传背景中存在影响直链淀粉含量的修饰基因,表明在选育高直链淀粉玉米品系时,应当重视遗传背景的选择和修饰基因的累加。采用单粒法技术对分离后代进行直链淀粉含量和重量选择,有利于积累高直链淀粉修饰基因,是选育子粒饱满、高粒重的高直链淀粉玉米自交系的有效方法。     

Ae1-5180高直链淀粉玉米近等基因系农艺性状与子粒品质分析

高直链淀粉玉米品种选育具有广阔的应用前景和商业价值,目前,我国高直链淀粉玉米种质稀缺。显性Ae1-5180突变基因为直链淀粉扩充者ae的等位突变,对其育种应用研究鲜少报道。以10组优质玉米自交系及其Ae1-5180近等基因系为试验材料,通过对植株农艺性状和子粒品质分析发现,与对照相比,全部Ae1-5180近等基因系直链淀粉含量显著提高,同时总淀粉及百粒重降低。近等基因系CA240/Ae1和CANS-1/Ae1直链淀粉含量高,且百粒重较高,农艺性状变化小,推测具有较高的潜在育种价值。     

玉米雄性不育突变体ms1153的遗传分析与基因定位

以玉米雄性不育突变体ms1153为材料,通过减数分裂期花粉母细胞染色体观察和不同发育时期花药石蜡切片分析突变体不育表型产生的原因,利用F₁和F₂群体确定突变体MS1153的遗传方式和基因ms1153物理位置。结果表明,与野生型相比,突变体植株在营养生长期无明显差异,在生殖生长阶段花药不能从颖壳外露,成熟花粉粒内无淀粉积累。细胞学分析发现,突变体减数分裂过程正常,但减数分裂后绒毡层降解推迟。遗传分析表明,突变体ms1153的不育性状受1对隐性核基因控制。利用图位克隆的策略将MS1153基因定位于玉米第4染色体分子标记8243与8275之间,物理区间为221.4~226.2 Mb,此区间内没有已克隆雄性育性基因,说明MS1153是一个新的玉米雄性育性基因。     

玉米碳水化合物分配缺陷突变体ygl3的光合特性及遗传分析

以快中子辐射诱变玉米自交系PH6WC筛选得到的碳水化合物分配缺陷突变体ygl3为材料,通过叶片内叶绿素含量和碳水化合物含量的测定、叶绿体结构显微观察、光合特性和遗传特性等进行分析。结果表明,与野生型相比,突变体叶绿体数目变少,形态松散,维管束鞘叶绿体积累了大量的淀粉,淀粉颗粒排列不规则且体积增大,导致了叶绿体的膨胀和膜结构的破坏;叶片中淀粉、葡萄糖、果糖的含量都显著高于野生型,表现出玉米碳水化合物分配缺陷的典型表型特征;突变体的叶绿素a、叶绿素b及总叶绿素含量都显著低于野生型;净光合速率(Photo)、气孔导度(Cond)、蒸腾速率(Trmmol)均极显著低于野生型,胞间二氧化碳浓度(Ci)高于野生型。遗传分析表明,(ygl3×Mo17) F₂分离群体突变型(黄化)与野生型(绿色)植株性状分离符合1∶3分离比例,表明该突变体受单个核隐性基因控制。     

玉米胚乳突变基因ae1和du1的遗传效应

利用玉米ae1和du1隐性纯和突变自交系与普通玉米自交系48-2的杂交F1、F2代子粒为研究材料,通过单粒法测定子粒的直链淀粉含量和重量,用于分析玉米胚乳突变基因ae1和du1的遗传效应.结果表明:F2代中具有ae1或者du1纯和突变的子粒表皮皱缩,重量明显下降,直链淀粉含量显著提高.在ae1与du1的杂交后代中,子粒的单粒重和直链淀粉含量没有显著变化,表明伽ae1与du1双突变并不能导致直链淀粉含量增加.单突变的ae1和du1群体内各子粒间的直链淀粉含量和重量差异较大,说明遗传背景中存在影响直链淀粉含量的修饰基因,表明在选育高直链淀粉玉米品系时,应当重视遗传背景的选择和修饰基因的累加.采用单粒法技术对分离后代进行直链淀粉含量和重量选择,有利于积累高直链淀粉修饰基因,是选育子粒饱满、高粒重的高直链淀粉玉米自交系的有效方法.     

利用分子标记定位玉米小粒突变体mn7基因的研究

利用甲基磺酸乙酯(EMS)对玉米自交系郑 58进行诱变，获得 1个可以稳定遗传的小粒突变体mn7(miniature 7)。mn7成熟子粒表现为体积变小、子粒偏白、胚乳发育缓慢，百粒重降低 60.2%，粒长、粒宽、粒厚均极显著降低。mn7突变体的子粒在授粉后 15 d即可观察到明显小于野生型的子粒。对其自交后代和回交后代的遗传分析表明，该性状受隐性单基因控制。用mn7纯合体与自选玉米自交系 19HL3012杂交构建的包含 348个个体的 F₂分离群体，将该基因定位于玉米第 7染色体上 bin7.02区域内分子标记 umc2327和 SYM232之间 5.8 cM的范围内，距umc2327为 4.4 cM，距 SYM232为 1.4 cM。初步的生物信息学分析表明， mn7可能是 1个新基因或新等位基因。     

玉米株型性状QTLs作图群体分析

玉米紧凑株型对于提高种植密度,增加单位面积产量,满足玉米生产发展的需求具有重要的意义。试验以株型紧凑和松散的优良玉米自交系豫82、豫87-1为亲本,组配和构建F_2∶3家系,以其作为株型性状QTLs定位与分析的作图群体。通过对株型6个相关性状,株高、穗位高、叶长、叶宽、叶夹角、叶向值在郑州、三亚两个地点的研究表明,亲本自交系在株型性状上存在显著差异,其后代F_2∶3家系间存在显著差异,各株型性状均呈连续变异、正态分布,说明所选材料适合作为QTLs定位与分析的作图群体。     

过量表达拟南芥GPX3基因提高玉米苗期抗旱性研究

通过农杆菌介导法将拟南芥抗旱基因AtGPX3导入玉米自交系郑58中,用PCR和RT-PCR法对转化玉米进行检测,在水分胁迫下对T₁代转基因玉米和非转基因玉米进行抗旱性分析。结果表明,共得到56株转化苗,检测获得9个株系的30株T₀代转基因阳性植株,抗性植株阳性率为53.6%。RT-PCR检测表明,T₁代有6个株系为稳定遗传阳性株系,并且AtGPX3基因在转基因玉米中表达量大幅度提高。耐旱性分析表明,非胁迫条件下,非转基因和转基因株系中游离脯氨酸（Pro）和丙二醛（MDA）的含量基本无显著差异。在干旱胁迫条件下,转基因玉米叶片的Pro含量高于非转基因玉米,比非转基因株系提高了46.2%;MDA含量低于非转基因玉米,比非转基因玉米下降了34%。通过导入AtGPX3基因,可以提高玉米苗期的耐旱性。     

普通玉米单交种与高油玉米杂交当代子粒化学成分的遗传分析

试验以吉林省主推的普通玉米单交种为母本,以高油玉米为父本进行人工杂交,研究双亲对杂交当代子粒的脂肪、蛋白质和淀粉含量的影响.结果表明:①母本对杂交当代子粒脂肪含量的影响大于父本,杂交当代子粒的脂肪含量与其双亲的关系是:普通玉米单交种×高油玉米自交系杂交当代子粒的脂肪含量=0.60P₁+0.40P₂;普通玉米单交种×高油玉米单交种杂交当代子粒的脂肪含量=0.65P₁+0.35P₂;普通玉米单交种×高油玉米群体的杂交当代子     

玉米杂交F1代秃尖与亲本秃尖相关性研究

本文以农大玉米育种试验1999年的自交系试验圃和杂交鉴定圃为材料,运用相关及回归分析的方法,研究了133对玉米杂交组合的杂种F₁与双亲的秃尖、双亲秃尖均值的相关性、双亲秃尖之差绝对值的相关性,并利用回归方程根据双亲秃尖,双亲秃尖均值,双亲秃尖之差绝对值的变化对F₁代秃尖的影响进行数据分析。     

Opaque2基因对糯玉米子粒品质的影响分析

玉米Opaque2(O2)基因突变显著影响子粒胚乳中蛋白体形成、淀粉含量、氨基酸组成等,其中,赖氨酸含量提高使营养品质大幅度提升。通过回交转育的方法构建17份糯玉米o2近等基因系,对子粒表型、种皮厚度、百粒重和粗淀粉含量等性状分析。结果表明,与对照相比,16个近等基因系子粒明显皱缩、胚乳变为粉质,6个近等基因系种皮厚度增加,11个近等基因系百粒重显著降低,12个近等基因系子粒粗淀粉含量显著降低。由此表明,o2基因的导入对糯玉米子粒表型、产量、淀粉含量等主要起负调控作用,影响程度与导入背景密切相关。     

Starch swelling power and amylose content of triticale and Triticum timopheevii germplasm

Triticale (× Triticosecale Whittmack) and Triticum timopheevii have undergone little selection relative to other grains for quality characters, including starch amylose content. Using starch swelling power (SSP) in water and spectrophotometric analysis of the iodine binding ratio, 247 lines of triticale and 20 lines of T. timopheevii were screened for amylose content. Following this, the expression of the starch-forming protein granule-bound starch synthase (GBSS) in triticale was investigated by SDS-PAGE in the eight highest and eight lowest SSP lines. A strong correlation (R² = 0.8174) was found between iodine binding and SSP. The SSP of T. timopheevii lines ranged from 13.7 to 16.7, indicating an approximate range of amylose content from 28.1 to 33.8%: a small range within typical results from commercial wheat cultivars. The SSP of triticale ranged from 12.5 to 23.6 suggesting amylose content ranged from 12.8 to 35.1%: a much wider range reflecting the contribution of both the wheat and rye genomes. It appeared that expression of GBSS-4A was down-regulated in low amylose lines. Therefore there is significant potential to select for amylose content in triticale to increase quality in both the animal and human feed markets.     

延缓叶片衰老ZmIPT2基因的玉米遗传转化及功能验证

从玉米自交系郑58中克隆Zm IPT2基因并构建单子叶植物表达载体,通过农杆菌侵染萌动胚方法将其转入玉米自交系K10中,对转基因后代进行分子检测和功能验证。结果表明,Zm IPT2基因c DNA全长969 bp,成功构建其单子叶植物表达载体p CAMBIA5300-ubi-Zm IPT2。农杆菌侵染萌动胚法共转化K10种子5 163粒,获得T0代PCR阳性幼苗48株,其中13株结实收获种子;获得的3个T2代株系PCR阳性率符合3∶1的分离比,且RT-PCR检测呈阳性;2个T2代转基因株系的成熟期叶绿素含量和细胞分裂素含量极显著高于对照,相对绿叶面积和叶面积持绿期极显著或显著高于对照,百粒重和小区产量显著高于对照。结果初步证明,Zm IPT2基因在玉米中的过表达可延缓叶片衰老,提高玉米产量。     

半粒玉米胚乳直链淀粉含量测定方法的研究

淀粉是玉米作为工业原料最主要的产品,其中直链淀粉在工业上用途更为广泛。玉米直链淀粉含量直接影响玉米淀粉品质,也是高直链淀粉玉米选育的重要指标。测定半粒玉米直链淀粉含量对玉米品质育种早代材料的筛选尤为重要。本实验对半粒玉米样品的前处理及其直链淀粉含量的碘比色测定法进行了研究,提出了半粒玉米样品的直链淀粉含量测定方法。该方法简便有效,可以减少早期选种的盲目性,加快育种进程。     

Sec-1位点缺失对1BL/1RS易位系籽粒品质的影响

为了解 Sec-1位点缺失对1BL/1RS易位系品质的影响,用 Sec-1位点缺失突变体与郑麦7698多次回交,系谱法辅助分子标记多代选择后得到 Sec-1位点缺失的1BL/1RS易位系（简称 Sec-1位点缺失易位系）和正常1BL/1RS易位系（简称正常易位系）,并进行品质性状、抗病性及农艺性状鉴定。结果表明,蛋白质含量、湿面筋含量、干面筋含量和中峰值高度在 Sec-1位点缺失易位系和正常易位系之间差异不显著,而 Sec-1位点缺失易位系的面筋指数、面团形成时间、稳定时间、粉质质量指数、和面时间、中峰值宽度和8 min尾宽显著高于正常易位系。正常易位系的吸水率和衰落角显著大于 Sec-1位点缺失易位系。 Sec-1位点缺失易位系的条锈病抗性和白粉病抗性均低于正常易位系,但二者之间条锈病的病情指数差异不显著,而白粉病的病情指数差异达显著水平。正常易位系与 Sec-1位点缺失易位系间的千粒重、穗粒数、产量水平差异均不显著。综上所述, Sec-1位点缺失对小麦籽粒品质的正向调控作用显著,而对农艺性状的负面效应不显著, Sec-1位点缺失突变体是研究和改良小麦籽粒品质的优良遗传材料。     

玉米杂交当代优势研究进展

杂种优势利用是玉米种质遗传改良与技术创新的理论基础。利用杂交当代(F₀)优势来提高玉米子粒产量和改善品质是研究的重点。综述了近年来玉米杂交当代优势的研究进展,并探讨了杂种当代优势有效利用的主要途径。     

The Null-4A Allele at the Waxy Locus in Durum Wheat affects Pasta Cooking Quality

Granule-bound starch synthase, also known as the waxy protein catalyses the synthesis of amylose in wheat endosperm starch. In durum wheats, the genes encoding GBSS are present at the two Wx loci on chromosome 7A and 4A (a segment of 7B that has been translocated). Several null Wx-B1 (missing GBSS protein from chromosome 4A) durum lines were produced from crosses with null-4A bread wheats backcrossed to durum wheats. Semolina milled from 4 normal and 7 null-4A durum wheat lines grown over two seasons (1999 and 2000) in South Australia were analysed for amylose content, starch pasting properties as measured by the Rapid Viscoanalyzer (RVA), swelling power and starch damage, protein content and electrophoretic protein analysis. Spaghetti was prepared with a micro-scale extruder and the cooked pasta evaluated for cooking loss, firmness, stickiness and water absorption. The null-4A lines had significantly lower (ca. 5%) amylose content, higher starch peak viscosities and semolina swelling power. The pasta derived from the null-4A lines had lower cooking loss and in 1999 was more adhesive than the non-waxy lines. Cooking loss was correlated with amylose content, peak starch viscosity, swelling power of semolina and cooked pasta adhesiveness. Semolina swelling power was highly correlated with RVA peak viscosity. Waxy durum wheats appear to have an advantage over the normal types in terms of lower cooking loss, widely used as an indicator of pasta cooking quality.     

Analysis of starch swelling power in Australian breeding lines of hexaploid wheat (Triticum aestivum L.)

Starch is the major component of wheat (Triticum aestivum L.) grain and is composed of two large glucan molecules, amylose and amylopectin. The ratio between the two polymers types influences the water absorbing properties of starch upon heating, and thus affects the end-use of grain and purified starch. In this study, we evaluated the starch swelling power (SSP) values in seven wheat populations developed from crosses involving low-SSP lines. Analysis of starch produced by the F₂ generation plants showed that the largest SSP variation (11.4–16.2) and lowest SSP mean (13.9) was obtained for a population derived from doubled haploid lines SM1028 (SSP = 14.5) and VK306 (SSP = 13.6). The population of 360 lines was advanced by single seed descent to the following generations for further studies. Starch analysis of grain produced by F₄ generation lines in two field locations during 2006 and in a greenhouse environment during 2005 showed that SSP values were relatively stably inherited. The average broad-sense heritability was 73% and significant (P < 0.001) genotype × genotype and genotype × environment interactions were seen. Starches with the highest and lowest SSP values were inversely related to amylose concentration determined by high pressure liquid chromatography (HPLC)–size exclusion chromatography (SEC) of debranched starch. Developed lines with the lowest SSP values surpassed 40% in apparent amylose concentration. The study illustrates that screening for SSP in early generations can be used to develop wheat lines with desired starch swelling characteristics.