Biserrula pelecinus L. is a promising forage legume for the central Ethiopian highlands

The availability of effective inoculant rhizobia is often critical to the successful development of productive forage legumes. Biserrula pelecinus L. is a legume with potential as forage in Ethiopia to improve livestock feed quality and soil fertility. B. pelecinus can form N₂‐fixing symbiosis with rhizobia in the genus Mesorhizobium. This study investigated the N₂ fixation effectiveness of 15 B. pelecinus‐nodulating Mesorhizobium strains on two subspecies of B. pelecinus (B. pelecinus ssp. leiocarpa, native to Ethiopia, and the introduced B. pelecinus ssp. pelecinus). The most effective strain (WSM3873) on both subspecies was assessed at two sites; one with pre‐existing populations of B. pelecinus‐nodulating rhizobia (Modjo), and one without (Holeta). No inoculation response was observed at Modjo when B. pelecinus ssp. pelecinus was inoculated with WSM3873 alone, however, biomass yield was greatest (11.5 tonne DM/ha) following inoculation along with co‐application of phosphorus and nitrogen. At Holeta, a strong inoculation response was achieved with WSM3873 alone on B. pelecinus ssp. pelecinus. In contrast, B. pelecinus ssp. leiocarpa did not show any response at Modjo and failed to emerge after sowing at Holeta. While the native legume B. pelecinus ssp. leiocarpa appears poorly suited to development as a forage, B. pelecinus ssp. pelecinus and WSM3873 represents a promising legume‐rhizobia symbiosis that could benefit farming systems of the central Ethiopian highlands.     

春化及光周期基因的等位变异对小麦主要农艺性状及产量的影响

为了解春化及光周期基因对小麦生育期、农艺性状及产量的影响,以田间种植的253份国内外小麦品种（系）为材料,利用分子标记检测其春化基因（Vrn-1）和光周期基因（ Ppd-D1）的等位变异,记录其抽穗期、开花期,在灌浆中期调查其株高、成穗数等农艺性状,收获后调查其产量性状。结果表明,供试材料中包含13种春化和光周期基因等位变异组合类型,其中含有 vrn-A1+vrn-B1+vrn-D1+Ppd-D1a组合的材料最多,占59.68%; Vrn-1+Ppd-D1a 组合可显著缩短小麦播种至开花所需的时间。含有 Vrn-A1a或 Vrn-B1材料的成穗数显著多于含有 Vrn-D1 或 vrn-1的材料,但含有 Vrn-1不同等位变异的材料间产量无显著差异;含有 Vrn-A1a材料的旗叶长而窄。与含有 Ppd-D1b的小麦材料相比,含有 Ppd-D1a的材料开花期显著提前,且株高降低,同时穗下茎长、旗叶长和倒二叶长均显著缩短。综上,春化及光周期基因在影响小麦抽穗开花期的同时,对农艺性状和产量也有重要影响;含有 Vrn-D1+ Ppd-D1a组合的小麦材料在生育期稳定性、产量等性状上均表现优异,在育种中可多加利用。     

黄淮麦区（南片）小麦粒重基因 TaGS-D1和 TaCwi-A1等位变异检测及效应分析

小麦粒重是影响小麦产量的重要因素,为了解小麦粒重基因 TaGS-D1和 TaCwi-A1及其等位变异在黄淮麦区（南片）新育成小麦品种（系）中的分布情况,以94份黄淮麦区（南片）新育成小麦品种（系）为试验材料,利用功能标记GS7D、CWI22和CWI21对试验材料中 TaGS-D1和 TaCwi-A1位点的等位变异进行检测,并分析了不同等位基因以及等位基因组合与粒重之间的关系。结果表明,在 TaGS-D1位点,共检测到 TaGS-D1a和 TaGS-D1b两种等位基因,分布频率分别为80.85%和19.15%,含有 TaGS-D1a等位基因的小麦材料的粒重显著高于含有 TaGS-D1b等位基因的材料;在 TaCwi-A1位点,共检测到 TaCwi-A1a和 TaCwi-A1b两种等位基因,分布频率分别为67.02%和32.98%,含有 TaCwi-A1a等位基因的小麦材料的粒重显著高于含有 TaCwi-A1b等位基因的材料;在 TaGS-D1和 TaCwi-A1位点,共检测到 TaGS-D1a/TaCwi-A1a、 TaGS-D1a/TaCwi-A1b、 TaGS-D1b/TaCwi-A1a和 TaGS-D1b/TaCwi-A1b四种等位基因组合,分布频率分别为56.38%、24.47%、10.64%和8.51%,含有 TaGS-D1a/TaCwi-A1a等位基因组合的小麦材料的粒重显著高于具有其余三种等位基因组合的材料,含有 TaGS-D1b/TaCwi-A1b等位基因组合的小麦材料的粒重显著低于具有其余三种等位基因组合的材料。     

冬小麦品种高低分子量麦谷蛋白亚基的分子标记检测

为了通过育种手段尽快改良小麦加工品质,利用Dx5、By8、By9、By16、Glu-A3、Glu-B3和1B.1R的特异性分子标记对221份中国冬小麦品种（系）进行HMW-GS、LMW-GS基因的等位变异及1B.1R易位系检测,结果表明：（1）在所检测的小麦品种（系）中,含Dx5、By8、By9的材料依次为58、79、119份,频率依次为26.2%、35.7%、53.8%;未检测到含By16的材料。（2）在所检测的小麦品种（系）中,Glu-A3位点上,含Glu-A3a、Glu-A3b、Glu-A3c、Glu-A3d的材料依次为30、1、111、79份,频率依次为13.6%、0.5%、50.2%、35.7%;未检测到携带Glu-A3e、Glu-A3f、Glu-A3g的材料;Glu-B3位点上,含Glu-B3d、Glu-B3g、Glu-B3f、Glu-B3h的材料较多,依次为64、47、18、11份,频率依次为29.0%、21.3%、8.1%、5.0%,含Glu-B3a、Glu-B3b、Glu-B3c、Glu-B3i的材料很少,依次为1、3、2、4份,频率依次为0.5%、1.4%、0.9%、1.8%;含1B.1R易位系的材料（即Glu-B3j类型）71份,频率为32.1%;未检测到含Glu-B3e的材料。（3）在所检测的小麦品种（系）中含最优亚基组合By8、Dx5、GluA3d、GluB3d的材料只有2份,频率为0.9%,说明聚合多个优良基因的小麦品质改良工作急需加强。     

宁夏小麦黄色素含量相关基因的组成与分布

选育低黄色素含量品种是宁夏小麦品质改良的重要目标之一。为阐明宁夏小麦中控制籽粒黄色素含量基因TaZds-A1和TaZds-D1的组成及分布特点,利用其功能标记YP2A-1和YP2D-1对91份小麦品种进行检测与分析。结果表明,在TaZds-A1位点,等位变异TaZds-A1a(与低黄色素含量相关)和TaZdsA1b(与高黄色素含量相关)分别占59.3%和40.7%;在TaZds-D1位点,等位变异TaZds-D1a(与高黄色素含量相关)占95.6%,TaZds-D1b(与低黄色素含量相关)仅占4.4%。宁夏小麦黄色素含量基因位点存在4种等位变异组合类型:以TaZds-A1a/TaZds-D1a(57.1%)组合类型为主,TaZds-A1b/TaZds-D1a(38.5%)组合类型次之,TaZds-A1a/TaZds-D1b和TaZds-A1b/TaZds-D1b组合类型最低(2.2%);不同等位变异组合类型在不同地区间的分布比例也不同。     

四川小麦品种高、低分子量麦谷蛋白基因和1B/1R易位的分子标记鉴定

为给四川小麦品质育种提供参考信息,利用7个HMW-GS、17个LMW-GS和1个1B/1R易位的特异分子标记,对105份2000年后育成的四川小麦品种进行上述基因检测。结果表明:(1)针对HMWGS,在Glu-A1位点,含Ax2*的品种有2份,频率为1.9%;在Glu-B1位点,含Bx7、Bx20、Bx17、By8和By9的品种分别有73、26、4、45和30份,频率分别为69.5%、24.8%、3.8%、42.9%和28.6%,未检测到含Bx7OE的品种;在Glu-D1位点,含Dx5的品种有65份,频率为61.9%。(2)针对LMW-GS,在Glu-A3位点,含Glu-A3a、Glu-A3b、Glu-A3c、Glu-A3d和Glu-A3f的品种分别有2、2、63、29和9份,频率分别为1.9%、1.9%、60.0%、27.6%和8.6%,未检测到含Glu-A3e和Glu-A3g的品种;在Glu-B3位点,含Glu-B3b、Glu-B3d、Glu-B3f、GluB3g和Glu-B3i的品种分别有18、10、1、75和1份,频率分别为17.1%、9.5%、1.0%、71.4%和1.0%,未检测到含Glu-B3a、Glu-B3c、Glu-B3e和Glu-B3h的品种。(3)含1B/1R易位的品种有36份,频率为34.3%。(4)组合6种和5种以上优质基因的品种分别有2份(频率为3.8%)和15份(频率为14.3%)。可利用这些品种作为亲本,在四川小麦品质育种中逐步导入优质基因Ax2*、Bx7、By8、Dx5、Glu-A3d、Glu-B3d、Glu-A3b和Glu-B3b,并淘汰1B/1R易位,优化四川小麦面筋优质基因组成。     

Effects of crop rotation and granular nematicides on the incidence ofVerticillium dahliae Kleb. andColletotrichum coccodes (Wallr.) Hughes,in potato

Summary The incidence ofVerticillium dahliae andColletotrichum coccodes was studied in a crop rotation experiment on sandy soil from 1983 to 1986. Early in the growing season the percentage of stems infected byV. dahliae increased with increasing cropping frequency of potato, depending on the cropping sequence, and decreased with the application of granular nematicides. However, later in the growing season the initial differences decreased.C. coccodes infections of stems were not affected by these factors. The percentage of plants infected byV. dahliae closely correlated with the percentage of plants with wilt symptoms but this relationship was absent forC. coccodes. Early in the growing season, the more vigorous the plants, the greater the level ofV. dahliae infection. Soil infestation withV. dahliae increased with increasing cropping frequency of potato but was not affected by annual applications of granular nematicides.     

47份外引小麦种质中矮秆基因的检测及其降秆效应分析

为有效利用外引小麦种质资源,明确矮秆基因的组成分布和降秆效应,利用8个矮秆基因( Rht-B1b、 Rht-D1b、 Rht4、 Rht5、 Rht8、 Rht9、 Rht12、 Rht13)的特异性分子标记分别对47份外引种质矮秆基因进行分子检测。结果表明,有46份种质含有矮秆基因,其中, Rht-B1b、 Rht4和 Rht12基因的频率最高,均为40.43%,其余依次为 Rht8(31.91%)、 Rht-D1b和 Rht13(均为19.15%)、 Rht5(8.51%)、 Rht9(6.38%)。有10份小麦种质含有单个矮秆基因,占21.28%;有36份小麦种质含有2个及以上矮秆基因,占76.60%,其中有11份含有3个矮秆基因,有2份含有4个矮秆基因。单个矮秆基因降秆效应以 Rht5最强,为31.78%,含有 Rht5的小麦材料平均株高为86.65cm。含有优良矮秆基因 Rht9、 Rht12和 Rht13的小麦材料平均株高分别为101.07 cm、92.87 cm和92.75 cm,其中, Rht9在8个矮秆基因中降秆效应最弱。     

基于光谱参数估算滴灌小麦干物质氮肥偏生产力和农学效率

为了解应用遥感技术估测滴灌小麦氮肥利用效率的可行性,以新春17号、新春6号和新春22号为材料,通过大田试验,分析了不同施氮处理下小麦干物质氮肥偏生产力(RDN)和干物质氮肥农学效率(DMA En)与光谱参数的相关关系,并建立小麦RDN和DMAEn的光谱参数估算模型.结果表明,在分蘖、抽穗和开花期RDN与绿度植被指数和比值植被指数呈极显著正相关,在拔节和抽穗期DMAEn与土壤调整比值植被指数和归一化差值植被指数呈显著正相关.光谱参数估算模型的均方根误差为7.64～33.31,说明利用光谱参数可以有效地估算小麦氮肥利用效率.     

Alternative hosts for potato mop-top virus, genus Pomovirus and its vectorSpongospora subterranea f.sp. subterranea

Summary Seventeen weed species common in the potato fields in Denmark were grown in a hydroponic system infested with viruliferous zoospores ofSpongospora subterranea f.sp.subterranea carrying potato mop-top virus (PMTV). The plants were examined for infection with PMTV andS.s.s. using DAS-ELISA and based on visible symptoms. Only two weed species were found to be infected with PMTV,Chenopodium album andSolanum nigrum, whereas 13 became infected withS.s.s. C. album was infected with PMTV by mechanical inoculation were the infection became systemically and the leaves showed necrotic spots.S. nigrum became local infected with PMTV by mechanical inoculation. By inoculation with viruliferousS.s.s. the roots ofS. nigrum became infected but in three weeks PMTV had not spread into the top of the plants.Nicotiana benthamiana was used as a control susceptible toS.s.s. and PMTV.     

69份国外小麦品种(系)抗叶锈性鉴定及基因分析

为给抗叶锈病育种提供优异抗源,选用17个不同毒力的叶锈菌生理小种,对69份国外小麦品种（系）及36份已知抗病基因的近等基因系进行苗期抗叶锈病基因推导,并结合11个已知基因的分子标记进行标记检测;于2017-2018年度分别在河北保定试验田和河南周口黄泛区农场对69份国外小麦材料进行田间成株期抗叶锈性鉴定。结果发现,在69份国外小麦品种（系）中共检测到6个抗小麦叶锈病基因 （Lr1、Lr10、Lr19、Lr26、Lr34和Lr37）,携带苗期抗病基因Lr1、Lr10、Lr19和Lr26的分别有6、19、5和10份品种（系）,携带成株抗病基因Lr34和Lr37的分别有10和26份品种（系）,田间鉴定具有成株慢锈性的品种（系）共有46份。     

玉米秸秆深翻还田土壤氨氧化细菌amoA基因多样性分析

以常规旋耕无秸秆还田(对照)、1年秸秆深翻还田、2年秸秆深翻还田土壤总DNA为模板,采用氨氧化细菌(Ammonia-oxidizing bacteria,AOB)的氨单加氧酶α亚基(amo A)基因特异性引物扩增AOB amo A基因,构建amo A基因文库。运用BLAST程序进行序列比较发现,玉米秸秆深翻还田土壤中分布有亚硝化弧菌属(Nitrosovibrio)、亚硝化螺菌属(Nitrosospira)和亚硝化单胞菌属(Nitrosomonas)微生物菌群,秸秆深翻还田土壤AOB amo A基因序列主要与保护性耕作、长期施肥、间作、温室和植被恢复土壤中的amo A基因序列相似;常规旋耕无秸秆还田土壤AOB amo A基因序列主要与秸秆焚烧大田土壤和内蒙古草原土的amo A基因序列相似。玉米秸秆深翻还田2年处理(SF-Ⅱ)AOB amo A基因多样性指数最高,其次是玉米秸秆深翻还田1年处理(SF-I),常规旋耕无秸秆还田(CK)最低。     

春化及光周期基因的等位变异及其对冬小麦光合及产量性状的影响

为了解春化及光周期基因对小麦光合及产量性状的影响,在抗旱棚中对冬麦区广泛种植的58个冬小麦品种进行水分胁迫和正常灌水处理,在灌浆期调查其光合性状,收获后调查其产量性状,并利用分子标记检测其春化及光周期基因的等位变异,进而分析在正常灌水和水分胁迫下春化及光周期基因的等位变异对光合及产量性状的影响。结果表明,供试材料中春化基因Vrn-B1和Vrn-D1位点的出现频率分别为8.62%和43.10%,未检测到春化基因Vrn-A1位点;光周期非敏感型位点Ppd-D1a的出现频率为91.38%。充分灌水条件下,含有vrn-D1位点的品种的净光合速率、蒸腾速率及单株生物量均较含有其显性位点的品种高,而在水分胁迫下,含有vrn-D1位点的品种仍能维持较高胞间CO2浓度、单株生物量及单株籽粒产量,表明该基因型可能更适应干旱环境。综上所述,春化及光周期基因对光合及产量性状有一定影响,携带vrn-D1位点的品种具有高且稳定的光合能力及产量水平,在小麦高光效育种中应注意利用。     

小麦高、低分子量麦谷蛋白亚基对品质性状的影响

为给小麦品质改良提供理论依据,以6个国家的532个品种(系)为材料,分析了小麦高、低分子量麦谷蛋白亚基与品质性状的关系。结果表明,各位点上不同的等位变异对品质性状的效应存在显著差异,亚基1、2*、17+18、5+10、GluA3f、GluB3b和GluB3g对面团形成时间和稳定时间具有显著的正向效应;亚基N、1、14+15、17+18、7+8、2+12、3+12、4+12、GluB3d、GluB3f、GluB3h和GluB3g对蛋白质和湿面筋含量具有显著正向效应;从亚基对品质性状的综合影响来看,1、17+18、GluA3f、GluB3g和GluB3f可作为优势亚基。具有1、17+18、2+12和1、17+18、5+10高分子量麦谷蛋白亚基组合的品种(系)综合品质性状显著优于含有N、14+15、2+12亚基组合的品种(系);具有低分子量麦谷蛋白亚基组合GluA3c、GluB3g,GluA3d、GluB3g和GluA3f、GluB3b品种(系)的综合品质性状显著优于含有GluA3b、GluB3j亚基组合的品种(系)。     

小麦面粉色泽相关基因在河南地方品种中的分布

面粉色泽是小麦品质的重要指标,与色泽相关的低多酚氧化酶和高脂肪氧化酶活性是小麦品质育种的重要目标之一。为了明确河南省小麦地方品种中上述两类酶的基因分布情况,利用4个多酚氧化酶（polyphenoloxidase,PPO）和2个脂肪氧化酶（lipoxygenase,LOX）基因的功能标记对308份河南地方小麦品种进行检测。结果表明,基因 PPO-A1a、 PPO-A1b在306个品种中具有明确检测结果,携带品种数量为132和174,频率为43.14%和56.86%;携带基因 PPO-D1a、 PPO-D1b、 TaLox-B1a、 TaLox-B1b的品种数量为282、26、21和287,其频率为 91.56%、91.56%、6.82%和93.18%。在306个品种中,携带低活性多酚氧化酶基因型组合（ PPO-A1b/ PPO-D1a）、较低活性多酚氧化酶基因型组合（ PPO-A1b/ PPO-D1b）、较高活性多酚氧化酶基因型组合（ PPO-A1a/ PPO-D1a）和高活性多酚氧化酶基因型组合（ PPO-A1a/ PPO-D1b）的品种数分别为166、114、10和16,其频率分别为54.25%、37.25%、3.27%和5.23%,具有 PPO-A1b/ PPO-D1a/ TaLox-B1a基因型的品种有11个,其频率为3.59%, PPO-A1a/ PPO-D1b/ TaLox-B1b基因型品种数为16个。     

The geographical distribution,inheritance and pest-resisting properties of sticky-tipped foliar hairs on potato species

Summary Near Cochabamba in Bolivia, plants ofSolanum berthaultii with sticky-tipped foliar hairs only have been collected but further south near Sucre, both sticky-tipped and pointed-tipped forms of this species and ofS. tarijense occur. Further south still, in Tarija, and in the border region of Argentina, only pointed-tippedS. tarijense has been collected but at Salta sticky-tippedS. tarijense has been found. InS. tarijense andS. herthaultii, the presence of sticky-tipped hairs (for which an aqueous fluoroscein solution is a selective stain) on adult foliage is controlled by a single dominant gene: plants with this character were more resistant to the aphidMyzus persicae and to the miteTetranychus urticae, and trapped more of the thripsThrips tabaci. In addition to the dominant gene, at least one set of recessive genes was needed for the full expression of this character in crosses withS. phureja and withS. tuberosum ev. Pentland Crown.T. urticae were trapped on second-generationS. tuberosum × berthaultii with this type of hair. Part of this work was done at the International Potato Center (CIP), Apartado 5969, Lima, Peru.     

Pyramiding of <Emphasis Type="Italic">Meloidogyne hapla</Emphasis> Resistance Genes in Potato Does Not Result in an Increase of Resistance

High levels of resistance against Meloidogyne hapla have been identified in wild species of tuber-bearing potatoes, but only QTL with partial effects have been identified so far in back crosses with cultivated potato. This study was designed to test if pyramiding of two previously identified resistance genes, R _Mh-tar and R _Mh-chc A, will result in improved or even an absolute level of resistance. R _Mh-tar and R _Mh-chc A introgressed from the wild tuber-bearing potato species Solanum tarijense and Solanum chacoense were combined in a segregating diploid Solanum tuberosum population. With the aid of AFLP markers, descendants from this segregating population were classified into four groups, carrying no R gene, with only R _Mh-tar , with only R _Mh-chc A and a group with the pyramided R _Mh-tar and R _Mh-chc A. Upon inoculation with M. hapla isolate Bovensmilde, the group containing only R _Mh-chc A showed a decline of 88% in average number of developed egg masses compared to the group without R _Mh-chc A and R _Mh-tar . The group of genotypes containing only R _Mh-tar , but not R _Mh-chc A, showed a decline of 55% in the number of developed egg masses compared to the group without R _Mh-chc A and R _Mh-tar . Unfortunately, the latter effect of R _Mh-tar was not significant. The effect of both loci, R _Mh-tar and R _Mh-chc A combined, did not further reduce the number of egg masses compared to the level of R _Mh-chc A alone.     

Role of the Y134F mutation in cyp51 and overexpression of cyp51 in the sensitivity response of Puccinia triticina to epoxiconazole

A collection of 110 isolates of Puccinia triticina in 2007 from different European wheat-growing regions were examined for their sensitivity to the demethylation inhibiting (DMI) fungicide epoxiconazole and the expression and mutations of the target gene, cyp51. The cyp51 gene was highly conserved across Europe. A mutation at codon 134 (Y134F) was identified in only five isolates. This mutation had a limited impact, if any, on the sensitivity of P. triticina towards epoxiconazole. Over the entire collection of isolates, cyp51 expression and in vitro sensitivity towards epoxiconazole was moderately correlated. A constitutive up-regulation of the cyp51 gene was detected in some of the isolates with higher ED₅₀ values. Such up-regulation was not inducible by exposure to different concentrations of epoxiconazole. Isolates of P. triticina with the highest ED₅₀ values and with the Y134F mutation in the cyp51 gene or with cyp51 overexpression were equally well controlled in vivo by registered field rates of epoxiconazole as compared to an isolate with the lowest ED₅₀ value.     

江苏淮北地区小麦品种资源籽粒硬度基因等位变异的KASP检测

为了解江苏淮北地区小麦品种资源的籽粒硬度概况及硬度基因型分布规律,以74份近年来江苏淮北地区所育品种(系)和38份来自黄淮其他麦区的常用亲本为材料,采用单籽粒谷物硬度测试仪、KASP标记检测技术和基因扩增及测序技术对其SKCS硬度值及硬度基因型进行鉴定。硬度检测结果表明,供试小麦品种(系)硬度变化范围较大,但硬质麦的比例最大,为70.5%。与常用亲本相比,江苏淮北地区育成品种中软质麦比例较高,为34.3%,但在高代品系中软质麦比例下降到20.5%。基因型检测结果表明,在Puroindoline-D1位点,供试品种(系)中共检测到4种基因型,即野生型(Pina-D1a/Pinb-D1a)、Pina-D1b、Pinb-D1b和Pinb-D1p,其频率依次为25.0%、2.7%、67.9%和4.5%。其中,野生型和Pinb-D1p主要分布在江苏淮北地区。不同硬度基因型的硬度值也存在差异,其中以Pina-D1b基因型的硬度值最高,野生型(Pina-D1a/Pinb-D1a)硬度值最低,Pinb-D1b和Pinb-D1p两硬质类型的籽粒硬度没有显著性差异。在Pinb-2位点,供试品种(系)中共检测到25份材料为Pinb-B2b基因型,包含21份硬质麦、2份混合麦和2份软质麦,其平均硬度值为63.8。     

玉米圆斑病拮抗菌芽孢杆菌21的鉴定及抑菌研究

利用形态特征、培养性状、生理生化特征及16Sr DNA序列分析,对获得的具有生防潜力的芽孢杆菌21进行鉴定,确定该菌株为枯草芽孢杆菌(Bacillus subtilis spp.)。利用显微观察法,研究枯草芽孢杆菌21对玉米圆斑病菌的抑制作用,结果显示,该菌株不同浓度发酵液处理后玉米圆斑病菌孢子萌发率出现下降趋势,萌发率最低为0;经发酵液处理后的玉米圆斑病菌芽管产生畸形,在发酵液浓度为90%时,芽管畸形最严重;处理后的玉米圆斑病菌菌丝出现畸形,菌丝中的内容物有外渗趋势。