Regenerative trait and cold hardiness in highly productive cultivars of alfalfa and red clover

Summary In earlier work on improvement of persistance in forage legumes, we selected genotypes from highly productive cultivars of alfalfa, Algonquin and Apica (Euphytica 45: 105–112, 1990) and cv. Florex red clover (Plant Cell Reports 8: 395–398, 1989) capable of in vitro regeneration from callus and cell culture. The alfalfa germplasm and its F₁ progeny as well as an F₂ red clover population were tested for cold stress tolerance. Plantlets were hardened in culture tubes at 2 or 5°C, 8h photoperiod, for at least four weeks and then subjected to freezing temperatures, –16 or –10°C for alfalfa and red clover, respectively. Survival of regenerative genotypes was significantly higher than of the non-regenerative ones in both species. A strong oositive correlation (r=0.78) between the regenerative trait and plant survival was found in alfalfa. The experiments indicate that in vitro selection for regenerative trait may improve cold stress tolerance of alfalfa and red clover.     

水稻萌发耐淹性种质资源筛选及QTL定位

作者用水培的方法研究水稻不同生育期缺磷的影响,结果证明：幼苗期缺磷的影响最显著,表现出生长缓慢,分蘖减少。因此,栽培水稻在幼苗期及分蘖期充分供应磷肥有特别重要意义。     

Simple sequence repeat markers linked to a major QTL controlling pod shattering in soybean

Shattering of soybean pods prior to harvest leads to a reduction in yield. In order to identify simple sequence repeat (SSR) markers linked to quantitative trait loci (QTLs) conditioning pod shattering, QTL analysis was conducted using an recombinant inbred line (RIL) population segregating for this trait. The degrees of pod‐shattering resistance were evaluated by heat treatment applied to pods harvested from plants in the field and in a growth chamber. Composite interval mapping identified one major QTL between SSR markers Sat_093 and Sat_366 on linkage group J for both environments. The position and the effect of this QTL were confirmed in an F₂ population derived from a cross between the pod shattering‐susceptible parental cultivar and a pod shattering‐resistant RIL. The SSR markers linked to the major QTL will be useful for marker‐assisted selection in soybean‐breeding programmes.     

Mapping a factor controlling the thermostability of seed lipoxygenase-1 in barley

Barley lipoxygenase (LOX)‐1 is believed to affect the stability of flavour and the foam of beer. The purpose of this study was to investigate the genetic variation of the LOX‐1 thermostability, and to analyse the mode of inheritance of this trait. A simple method was established to evaluate the LOX‐1 relative thermostability (LOX‐RTS). With this method, 153 barley cultivars were screened for LOX‐RTS. The frequency of the LOX‐RTS values was distributed in a bimodal manner. Based on these values, the barley lines were categorized into two groups: an H‐type with relatively thermostable LOX‐1 and an L‐type with relatively thermolabile LOX‐1. Using a ‘Steptoe’/‘Morex’ doubled haploid population, a major quantitative trait locus (QTL) associated with LOX‐RTS was identified on chromosome 4H of barley, explaining 82% of the variance. Mapping of a CAPS marker specific for the LoxA locus revealed co‐segregation with this QTL. In this study, the existence of the thermostability types of barley seed LOX‐1 and the locus controlling the thermostability were made clearer.     

普通小麦多酚氧化酶活性的QTL分析

多酚氧化酶（polyphenol oxidase, PPO）是引起面团（片）颜色褐变的主要原因。利用122对SSR引物、4对贮藏蛋白的STS引物和10对AFLP引物组合，分析了中优9507´CA9632的71个DH系的基因型，构建了由173个位点组成的遗传连锁图，在小麦21个连锁群上覆盖2 881 cM。将该群体种植于3种环境，采用复合区间作图法（CIM）进行了P     

基于高密度遗传图谱的玉米籽粒性状QTL定位

籽粒大小及百粒重是决定玉米产量的重要因素。为解析籽粒性状遗传基础,本研究以玉米自交系黄早四(HZS)和Mo17为亲本,构建包含130个重组自交系(recombination inbred line,RIL)的RIL群体。基于GBS(genotypingby-sequencing)技术获得的高密度多态性SNP(single nucleotide polymorphism)位点,构建了包含1262个Bin标记的高密度遗传图谱。采用完备区间作图法,对5个环境条件下的粒长、粒宽、百粒重、粒长/粒宽4个性状分别进行QTL(quantitative trait locus)定位,共检测到30个QTL。利用5个环境性状均值,共检测到11个QTL。其中粒长主效QTL qklen1、粒长/粒宽主效QTL qklw1在3个单环境条件下均被检测到,且定位在第1染色体相邻区域,物理位置分别为210~212 Mb、207~208 Mb,表型贡献率分别为22.60%和26.79%,被认为是控制玉米籽粒形状的主效位点。针对第1染色体207~212 Mb区间,采用成组法t检验,对黄早四(受体)和Mo17(供体)构建的BC3F1回交群体进行单标记分析。结果表明,在BC3F1群体中qklen1和qklw1同样具有显著的遗传效应。本研究结果不仅为分子标记辅助选择籽粒性状提供了实用标记,而且为主效基因的进一步精细定位和候选基因挖掘奠定了基础。     

Insect-mediated seed-set evaluation of 21 soybean lines segregating for male sterility at 10 different loci

The cowpea trypsin inhibitor gene (CpTI) and neomycin phosphotransferase gene (nptII) were introduced into the embryonic callus cells of immature embryos of wheat elite line Shannong 995604 using Agrobacterium-mediated gene transfer. Independent plantlets were regenerated from kanamycin-resistant calli. PCR and real time PCR analysis, PCR-Southern and Southern blot hybridization indicated that there were three independently-dervied transgenic plants viz. transformed-I, II and III (T-I, T-II and T-III). The segregation of CpTI in the transgenic wheat progenies of T-Iand T-III were consistent with Mendelian inheritance. Resistance to the storage insect pest of wheat viz. the grain moth (Sitotroga cerealella Olivier) was improved significantly in seeds of the three transgenic wheat T₂ lines obtained from T₁ PCR-positive plants. The frequency of moth-eaten seed from T-I, T-IIand T-III was reduced 66.76%, 62.48% and 43.59% respectively. The investigation of agronomic traits of the three transgenic wheat T₁ PCR-positive plants revealed that the three transgenic lines had excellent agronomic traits. They provide good germplasm resource for wheat genetic improvement.     

核不育亚麻不育性与标记性状的遗传观察

通过对Ｈ５Ａ不育系的Ｆ、Ｆ２（地不育株与可育株姐妹交及可育株自交）兄妹交、回交后代的性状观察，发现上述各群体后代中，只出现了白花、白种皮不育株和蓝花、褐种皮可育途中亲本型，而未出现重组类型。证明了不育性与花色、种皮颜色表现出不是紧密连锁就是完全连锁或一因多效。     

SSR-based genetic diversity assessment among Tunisian winter barley and relationship with morphological traits

For studying genetic diversity caused byselection for adaptation and end-use, 17microsatellites (SSR), representative ofthe barley genome, were used in 26 barley(Hordeum vulgare L.) accessions andcultivars in Tunisia. Theaccessions/cultivars originate fromdifferent geographic regions and are ofdifferent end-use. For the 15 polymorphicSSR, the mean number of alleles per locuswas 3.6 and the average polymorphisminformation content was 0.45. Clusteranalysis based on SSR data and onmorphological data clearly differentiatethe genotypes according to their type(local landraces vs. varieties), row-numberand end-use. The correlation between bothdiversity measures was highly significant(r = 0.25, p<10^-5) and thecorrespondence between the clustering basedon SSR and morphological data wasrelatively good. Our results show the largegenetic diversity of the Tunisian barleycultivars and the association of thisdiversity with adaptation traits.     

冬小麦品种籽粒物理品质性状及面粉品质性状的研究

以13个冬小麦品种(系)为材料，对其籽粒物理品质性状(包括千粒重、容重)和面粉品质性状(包括沉淀值、干、湿面筋含量)进行测定，并对各性状指标进行了相关分析和聚类分析，结果表明：容重与千粒重之间呈极显著正相关；干面筋与湿面筋间呈极显著正相关；沉淀值与干面筋呈极显著负相关；其他各指标间均无相关性。供试品种(系)大多数属于高容重、中千粒重、高沉淀值、中等面筋含量的品种。旨在为今后有计划的进行冬小麦品质改良提供信息和依据。