Use of crop models to understand genotype by environment interactions for drought in real-world and simulated plant breeding trials

Crop simulation models of plant processes capture the biological interactions between the sensing of signals at an organ level (e.g. drought affecting roots), the response of the plant at a biochemical level (e.g. change in development rate) and the result at the organ (or crop) level (e.g. reduced growth). In dissecting the complex control of phenotypes like yield, simulation models have several roles. Models have been used to generate an index of the climatic environment (e.g. of drought stress) for breeding programme trials. In wheat and sorghum grown in northern Australia, this has shown that mid-season drought generates large genotype by environment interaction. By defining gene action to calculate the value of input trait parameters to crop models, simulated multi-environment trials estimate the yield of ‘synthetic’ sorghum cultivars grown in historical or artificial climates with current or potential management regimes. In this way, the biological interactions among traits constrain the crop yields to only those that are biologically possible in the given set of environments. This allows the construction of datasets that are more ‘realistic’ representations of gene by trait by environment interaction than is possible using only the statistical attributes (e.g. means, variances and correlations) of real-world trait datasets. This approach has an additional advantage in that ‘biological and experimental noise’ can be manipulated separately. These ‘testbeds’ for statistical techniques can be extended to the interpretation of a crossing and selection programme where the processes of chromosomal recombination are simulated using a quantitative genetics model and applied to the trait parameters. Statisticians are challenged to develop improved methods for the resulting simulated phenotype datasets, with the objective of revealing the (known) underlying genetic and environment structure that was input to the simulations. These improved methods can then be applied to existing plant breeding programmes.     

大白菜核不育复等位基因的鉴定与分布

为摸清大白菜核不育复等位基因在3种生态型大白菜品系中的分布特性,利用基因型为MsMs的大白菜纯合显性雄性不育株为母本,与68个正常可育的直筒、卵圆和平头型大白菜可育品系杂交,统计后代育性分离比例,鉴定各品系基因型,计算不同生态型可育品系在核不育位点上的基因频率和基因型频率。结果表明,直筒型大白菜可育品系以纯合隐性基因型msms为主,占71.43%。可育基因ms频率为76.79%,恢复基因Msf频率为23.21%;卵圆型大白菜可育品系3种基因型MsfMsf,Msfms和msms分别占42.42%,39.40%和18.18%。Msf基因频率为62.12%,ms基因频率为37.88%;平头型大白菜可育品系以纯合隐性基因型msms为主,占57.14%。Msf基因频率为33.33%,ms基因频率为66.67%。直筒型和平头型大白菜可育品系的核不育复等位基因位点上以ms基因为主,而卵圆型大白菜可育品系的核不育复等位基因位点上以Msf基因为主。     

The expected utility of genetic information in beef cattle production

Scientific inquiry is increasing our knowledge of plant and animal genomics. The ability to specify heterogeneous production processes, to sort agricultural inputs by genotype, or to guide breeding programs to satisfy specific markets based on genetic expression may increase producer and consumer benefits. This research develops a decision analysis framework to assess the expected value of genetic information under risk aversion. Expected utilities are evaluated both with and without genetic trait information. Potential gains in the value of information can be quantified as research unravels the linkages between genetics and crop and animal performance and quality. An application to cattle feeding indicates potential gains to developing markets for specific animal genetic characteristics based on the amino acid sequence of the leptin gene.     

农杆菌敏感小麦基因型的筛选及其转化

利用C58c1农杆菌菌株（其携带的pPTN290质粒载体上含有nptⅡ 基因和GUS基因）为供体材料和小麦幼胚为受体材料,对我国35个春小麦基因型进行了农杆菌敏感性研究和转化研究。组织化学染色结果表明,PM97034、P187、巴140105、扬麦158、新春9号和克丰6号等基因型农杆菌感染后GUS基因瞬时表达率达到了15.0% ~ 30.0%,显著高于模式基因型Bobwhite。其余幼胚分别在含10-25mg/L G418培养基上诱导愈伤组织和分化植株,抗性再生植株经ELISA检测、PCR检测、叶片离体退绿检测、X-Gluc染色检测和Southerm blot检测,最终从新春9号和PM97034的农秆菌转化效率高于Bobwhite. Southerm blot检测结果同时表明,外源基因在多数转基因植株中表现为单拷贝整合。T₁代植株ELISA检测结果和PCR检测结果表明,外源基因在个别株系中的分离符合孟德尔遗传规律,而在多数株系中的分离偏离了孟德尔遗传规律。阳性植株与阴性植株分离比经X²。适合性检测,表明外源基因在多数株系中的遗传符合3：1分离规律。本文首次对不同小麦基因型进行了农秆菌敏感和转化效率研究,筛选到新春9号和PM97034两个对农杆菌比较敏感且转化效率比较高的基因型,可望广泛用于小麦转基因研究。     

适用于4种玉米基因型的农杆菌转化方法的探讨

利用改良的农杆菌培养液、侵染液、共培养培养基和筛选培养基等技术体系,对4个玉米基因型Hi-Ⅱ、H99、国内2个优良自交系R18-599和齐319的新鲜幼胚、预培养幼胚、胚性愈伤组织进行了农杆菌转化研究,并比较了不同共培养方式对农杆菌侵染不同玉米组织的影响。结果表明,Hi-Ⅱ新鲜幼胚在固体培养基上共培养和滤纸上共培养后GUS基因瞬间表达率分别为83.7%和4.4%,前法优于后法;Hi-Ⅱ新鲜幼胚、预培养3 d的幼胚愈伤组织经农杆菌侵染后GUS基因瞬间表达率分别为83.7%和12.1%,新鲜幼胚比预培养的幼胚愈伤组织更适合于农杆菌转化。用上述优化的条件对另外3个不同基因型的2种不同外植体H99、齐319(新鲜幼胚)和R18-599（胚性愈伤组织）进行遗传转化,共培养3 d后的GUS基因瞬间表达率分别为65.2%、52.6%和58%,表明该转化体系适合于上述4种基因型的幼胚和胚性愈伤组织的遗传转化。此外农杆菌侵染Hi-Ⅱ新鲜幼胚后经在含巴龙霉素25~100 mg L^-1培养基上3轮选择后,抗性愈伤组织获得率为2.4%,近似反映了本研究的遗传转化率。其他3个基因型的抗性愈伤也正在筛选中。结果初步表明,本研究建立的农杆菌介导的玉米遗传转化体系可能对4种基因型均适用。     

小麦籽粒淀粉分支酶同工酶基因型与酶活性关系研究

测定了71个小麦品种的籽粒淀粉分支酶活性,并采用非变性聚丙烯酰胺凝胶电泳（Native-PAGE）,鉴定了分支酶同工酶的基因型,以明确小麦籽粒淀粉分支酶（SBE）各同工型等位基因的分布特点和基因型组成,阐明分支酶活性与分支酶同工酶基因型的相关性。结果表明,分支酶有SBEⅠ和SBEⅡ两个基因位点,SBEⅡ位点未显现多态性,SBEⅠ位点存在多样性。在SBEⅠ位点鉴定出A、B、D_ⅰ和D_ⅱ共4个等位基因位点,各等位基因位点出现频率分别为9.9%、76.1%、95.8%和57.8%;共检测到9种基因型,其中基因型D_ⅰD_ⅱB、D_ⅰB和D_ⅰD_ⅱ有较高的分布频率,分别为45.1%、28.2%和8.5%。从单一位点分析,分支酶活性与SBEⅠ位点有显著的相关性,与SBEⅡ位点相关性不显著。由此可见,小麦籽粒胚乳淀粉分支酶同工酶不同基因位点和基因型对酶活性具有不同的遗传效应。     

糯玉米氮肥利用效率的基因型差异

以近年育成的31个糯玉米(Zea mays L. ceratina Kulesh)品种为试材,对其氮肥吸收利用率(RE)、氮肥生理利用率(PE)、氮肥农学利用率(AE)和氮肥偏生产力(PFP)的差异进行了比较。结果表明,各品种以收获鲜穗、鲜籽粒或成熟籽粒为目的,其AE、RE、PE和PFP均存在显著差异。聚类结果显示,无论收获产品是鲜穗、鲜籽粒还是成熟籽粒,属于高产、高氮肥利用效率(NUE)的品种有6个,即凤糯2146、京科糯267、京科糯218、粤白糯1号、SW42和SAUWX02。与其他品种相比,这6个糯玉米品种的鲜穗、鲜籽粒和成熟籽粒的平均产量分别高17.9%、18.1%和28.6%,平均AE分别高45.2%、50.2%和64.7%,平均RE分别高35.1%、35.1%和36.7%,平均PE分别高4.5%、9.7%和20.3%,平均PFP分别高17.9%、18.1%和28.6%。相关分析表明,提高糯玉米氮收获指数,增加氮素在植株体内的运转率有利于NUE的提高。     

广西蓖麻蚕品种间全茧量，茧层量遗传分析

通过对我所保育的蓖麻品种全茧量、茧层量这两个主要经济性状进行分析,结果表明,我所保育的21个蓖麻蚕品种仍然保持基因型和表现型的多样性,仍是一个有效的品种资源。各品种对环境的抗性有差异。     

用AMMI模型分析作物区域试验中的地点鉴别力

为了比较不同试验点在区域试验中鉴别力的大小,利用AMMI模型中地点的得分向量长度衡量地点鉴别力,并与传统的联合线性回归模型中的斜率进行了比较。以1995~96和1997~2000年度黄淮南片春水组小麦区域试验4年的产量数据为例进行了地点鉴别力分析。结果表明, AMMI模型比联合线性回归模型能更好地解释基因型与环境互作效应;多     

氮肥基因型差异对玉米吸氮量的反应

田间试验研究了11个玉米杂交种在不同施氮条件下的吸氮量。结果表明,玉米吸氮量具有明显的基因型差异。在低氮(N2)处理中,子粒、秸秆、地上部吸氮量高低品种相差分别为1.060、0.134、1.125g/kg,在高氮(N4)处理中,分别为0.836、0.154、0.954g/kg。不同基因型玉米的吸氮量差异低氮条件比高氮条件更大。施氮量对玉米吸氮量有显著的影响。玉米子粒、秸秆、地上部吸氮量和相应的产量呈极显著的正相关