三系粳稻不育系开花习性与异交结实率的关系

以583A、7740A7、7237A、春江12A、春江16A、春江26A、99-44A、宁67A、旱稻A等9个不同柱头外露率和花时的三系粳稻不育系为母本,以粳稻恢复系CH89为父本,进行大田小区制种,对不育系的午前花率、柱头外露率与异交结实率之间的关系进行了分析。结果表明,不育系柱头外露率与异交结实率之间的简单相关系数和偏相关系数以及午前花率与异交结实率之间的简单相关系数均达到显著水平,异交结实率与柱头外露率、午前花率之间的复相关系数也达到显著水平。粳稻不育系异交结实率(y)与柱头外露率(x1)、午前花率(x2)的回归方程为y=26.06 0.51x1 0.28x2。通径分析表明,柱头外露率对粳稻不育系异交结实率起更重要的作用。对三系粳稻不育系的遗传改良及制种策略进行了讨论。     

籼型细胞质雄性不育系不同性状与异交结实率的相关性和通径分析

试验研究了7个籼型水稻细胞质雄性不育系的6个不同性状与异交结实率的相关性,并对它们进行了通径分析.结果表明:(1)柱头外露率与异交结实率、张颖角度与异交结实率的相关系数分别为0.963和0.936.(2)柱头外露率对异交结实率的直接效应最大,其直接通径系数为0.8383.张颖时间对异交结实率的直接通径系数为0.4132.张颖角度和午前花率对异交结实率的直接效应亦都为正值,直接通径系数分别为0.1648和0.0271.柱头生活力系数和包颈粒率对异交结实率的直接效应均为负值,直接通径系数分别是-0.4811和-0.1020.     

水稻质核互作雄性不育系异交结实率的初步研究

为了研究水稻质核互作雄性不育系异交结实率与父母本的关系,以花籼A(野败胞质)、华农A(野败胞质)、华农A(夜公胞质)、华农A(饶平野稻胞质)共4个水稻质核互作雄性不育系为母本,以抗草种、T180、G72、金华占2号、华航1号、粤香占、HN5413、丰穗占、M22和M31共10个恢复系进行配组,结果表明:不同质核互作雄性不育系异交结实率存在显著的差异;不同恢复系间的异交结实率也存在显著差异;不育系和恢复系互作效应对异交结实率的影响不明显;同质异核不育系的异交结实率的差异达到显著水平,而同核异质不育系的异交结实率的差异不显著。这说明水稻质核互作雄性不育系异交结实率的差异主要受核内遗传物质的影响,细胞质对异交结实率的影响不明显。进而提出了在选育水稻质核互作雄性不育系时,不仅要注意优良异交开花习性,而且还要注意核内遗传物质对异交结实率的影响。     

粳稻异交相关性状对外源赤霉素敏感性的QTL定位研究

[目的]定位粳稻异交相关性状对外源赤霉素敏感性的QTL,为选育和改良高敏感性不育系提供理论依据。[方法]以粳稻秀水79与C堡及其杂交后代衍生的重组自交系群体260个株系为研究材料,研究其4个异交相关性状对外源赤霉素处理的敏感性并利用复合区间作图方法（CIM）对其QTL进行定位。[结果]控制剑叶角度对赤霉素敏感性的QTL共有3个,分别位于第3、9、9染色体上,其贡献率分别为5.59%,13.00%和11.80%,增效等位基因分别来自秀水79、C堡和C堡;控制株高对赤霉素敏感性的QTL共有2个,分别位于第1和8染色体上,其贡献率分别为8.46%和10.97%,增效等位基因分别来自秀水79和C堡;控制第1节间长度对赤霉素敏感性的QTL只有1个,位于第3染色体上,其贡献率为0.05%,增效等位基因来自C堡;控制第2节间长度对赤霉素敏感性的QTL也只有1个,位于第1染色体上,其贡献率为7.34%,增效等位基因来自C堡。[结论]该研究结果对减少杂交水稻制种过程中外源赤霉素的使用量、节约制种成本、降低对环境的污染具有重要意义。     

高异交率优质籼型不育系健645A的选育

湖南金健种业有限责任公司与常德市农科所合作用[珍汕97B×(菲改B×V20B)F10]F4×[(菲改B×V20B)F10×金23B]F4的F7代与优质稻黑宝的无色变异株杂交,经3 a 6代的定向选择得到优质人工制保材料(代号645),再与金23A测交并连续回交转育成优质野败型迟熟籼稻不育系健645A。该不育系不育性稳定,不育株率100%,花粉不育度100%,自交结实率为0,开花习性好,花时早,自然条件下柱头外露率高达82.39%,异交结实率高,繁殖制种产量高;米质优良,12项米质指标均达部颁优质米2级以上标准;生育期较长,配合力好,所配组合产量优势强,且米质优良。健645A于2006年2月通过湖南省农作物品种审定。     

优质、抗稻瘟病香型水稻三系不育系繁源A的选育

以长丰B为母本,乐丰B为父本杂交配组选育保持系,再与乐丰A测交、回交转育,育成野败籼型香稻三系不育系繁源A,于2013年通过福建省品种审定。结果表明,繁源A不育性稳定、配合力强、异交率高、抗稻瘟病、米质优异有香味。     

杂交水稻制种建立母本最佳穗层结构的探讨

将制种田中喷施“九二０”后的母本穗层划分为高层穗、表层穗、平颈穗、包颈穗４个层次。对各种类型穗层的受粉原理、自然受粉状态，与结实率的关系进行了研究分析，提出了母本最佳穗层结构模式，以及在实践中可以采取稀播壮秧、密植等６项农艺措施和配套措施，来建立起母本最佳穗层结构     

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 methods were greater than the     

Natural outcrossing rate in Vernonia galamensis

Vernonia galamensis is a potential new industrial crop growing wild in Ethiopia. The seed oil is rich in vernolic acid, an epoxy fatty acid, which is of interest for oleochemical uses. Basic information on the reproductive system of Vernonia is still very limited. The amount of natural outcrossing was estimated at two locations in Ethiopia (Alemaya and Babile) using flower colour as a marker. Single plants with white flowers, which is a monogenic recessive trait, were planted in plots with normal pink flowers and the outcrossing rate was estimated from the frequency of pink‐flowered plants in the progeny of the white‐flowered plants. Estimates of the natural outcrossing rate ranged between individual plants from 3.5 to 16% at Alemaya and 2.5 to 12% at Babile. Vernonia galamensis can be classified as a mainly self‐pollinated species.     

Out-crossing frequency and genetic analysis of hybrids between transgenic glufosinate herbicide-resistant rice and the weed, red rice

The potential of transferring herbicide resistance from transgenic rice (Oryza sativa L.) varieties to sexually compatible weeds is of paramount importance for development of effective weed control strategies. The objective of this research was to determine the genetic control and frequency of natural outcrossing between a transgenic, glufosinate-resistant rice line and a Louisiana biotype of red rice (Oryza sativa L.). Molecular and phenotypic data showed that outcrossing in field plots between a non-transgenic purple marker line and red rice did occur within one field season, but at a low rate of <1%. Similarly, molecular and phenotypic data demonstrated that glufosinate resistance was transferred from the transgenic line to the red rice biotype in the field within one year at a low frequency of 0.3%. Compared to parental lines, the transgenic-red rice hybrids were extremely late, tall, and never set seed during the normal field season. Genetic analyses in all F₂ populations showed glufosinate resistance behaved in a Mendelian fashion as a single, dominant gene. Presence of the bar gene for glufosinate resistance did not increase fitness or seed fecundity in hybrids or subsequent progeny. The genetic analyses and outcrossing results from this study suggest that an effective management program can be developed to prolong the usefulness of transgenic, glufosinate herbicide technology. This revised version was published online in July 2006 with corrections to the Cover Date.