Identification of PCR markers linked to different Or genes in sunflower

Broomrape is a parasitic plant that significantly decreases yield of sunflower. Breeding for resistance has proved to be the most efficient method for suppressing broomrape infestation in the field; however, new races of parasite constantly emerge, and new resistance genes need to be discovered and introduced into cultivated sunflower lines. The aim of this work was to test SSR markers from linkage group 3 (LG3) to investigate whether they could be used for identification of a particular Or gene. Twenty sunflower inbred lines were used, and polymorphism between the lines with various resistance genes and genetic background was investigated. The used markers revealed DNA polymorphism between the investigated lines. Strong association of markers from LG3 with Or₆, as well as Or₄ and Or₂ genes, was found. Identified markers could be used for introduction of these resistance genes into commercial sunflower lines and for establishment and identification of differential lines.     

Screening for resistance to broomrape (Orobanche cernua) in cultivated sunflower

Racial evolution of sunflower broomrape (Orobanche cernua) has been very rapid in Spain during recent years, in which resistance has been overcome several times and there has been an important increase in areas infested with this parasitic angiosperm. In order to find resistance to a highly virulent population of sunflower broomrape that could be used directly in breeding programmes, three different sets of cultivated plant material composed of 429 entries were tested by artificial inoculation. All evaluated inbred lines from Moden, Canada, were fully susceptible. Out of the 240 P.I. accessions tested, only 10 segregated for resistance to broomrape, the rest being susceptible. From the 160 USDA breeding lines evaluated, 5% were resistant and 19% segregated for resistance to O. cernua. These lines traced back mainly to crosses of RHA 274 and RHA 801 with Russian, Turkish and Romanian hybrids. The origin of P.I. accessions that segregated for resistance were primarily derived from the former USSR and from Romania.     

R-41, a sunflower restorer inbred line, carrying two genes for resistance against a highly virulent Spanish population of Orobanche cernua

The inheritance of resistance to a highly virulent population of sunflower broomrape (Orobanche cernua) has been studied in R-41, a Spanish sunflower restorer inbred line. Using the cytoplasmic male-sterile inbred line HA-89 (cms; very susceptible to this population of broomrape) as a female parent, progenies of the cross with R-41, i.e. Fl, F2 and BC1 to both parents, as well as the parental lines, were analysed for their reaction to the broomrape population EC-94. The goodness of fit of the observed vs expected segregation ratios indicated that the inheritance of resistance to broomrape in line R-41 is conferred by two independent dominant genes.     

不同向日葵品种根系分泌物对向日葵列当萌发的刺激作用

以不同列当抗性向日葵根系分泌物作为萌发刺激物,研究其对向日葵列当种子萌发的影响,探究不同向日葵品种对列当抗性差异响应的机制,为向日葵列当抗性品种的选育和应用提供理论依据。研究表明：根系分泌物的稀释倍数对向日葵列当的萌发具有显著影响,其中TP-3313和SH363-M根系分泌物在稀释50倍时达到最大萌发率,而3638C根系分泌物在稀释75倍时达到最大萌发率,整体表现为低浓度促进、高浓度抑制的特点;不同列当抗性的向日葵根系分泌物诱导向日葵列当萌发的效果不同,向日葵列当萌发率表现为TP-3313相似文献   

Reproductive behaviour and broomrape resistance in interspecific hybrids of sunflower

Interspecific hybrids and backcross generations between the wild perennial species Helianthus resinosus, Helianthus paucifiorus, Helianthus laevigatus, Helianthus nuttallii ssp. nuttallii T. & G. and Helianthus giganteus, resistant to broomrape (Orobanche cernua) and susceptible inbred lines were obtained to study crossability to cultivated sunflower and the transmission and expression of resistance to this parasitic weed. Conventional crosses with all the species tested were successful except for the crosses with diploid H. giganteus, for which embryo rescue techniques were needed to overcome hybrid incompatibility. Pollen viability and seed set were highest for F₁ hybrids with hexaploid species and lowest for those with the diploid H. giganteus. We evaluated F₁, BC₁F₁, some BC₂F₁ plants and the wild and cultivated parents. The wild species and interspecific hybrids were resistant to broomrape infection except for H. nuttallii, which showed segregation, indicating that the resistance is dominant. The crossability and resistance of F₁, and back-cross generations of species with different ploidy levels indicate that the transfer of broomrape resistance to cultivated sunflower is feasible.     

Inheritance of resistance to race F of broomrape in sunflower lines of different origins

A new race F of broomrape overcomes all known resistance genes in cultivated sunflower, but recently, sources of resistance against race F have been developed. The objective of the present research was to study the inheritance of resistance to race F in crosses between 12 resistant sunflower breeding lines, derived from three different sources of resistance, and the susceptible male‐sterile line P‐21. Parental lines and F₁, F₂, F₃ and BC₁ generations were evaluated for broomrape resistance. Segregations in the F₂ and BC₁ to resistant parent approached resistant to susceptible ratios of 1: 15 and 1: 3, respectively, in most of the crosses, suggesting a double dominant epistasis. However, segregations of 3: 13 and 1: 1 for F₂ and BC₁, respectively, indicating a dominant‐recessive epistasis, were also found. The F₃ data confirmed these results. Owing to the recessive nature of this resistance, it must be incorporated into both parental lines for developing resistant hybrid cultivars.     

Potential use of doubled haploid lines for the screening of resistance to yellow rust (Puccinia striiformis) in hexaploid wheat

Doubled haploid lines derived from anther culture of two Iranian spring wheat genotypes‘Ghods’susceptible and‘9106’resistant to yellow rust in Iranian field conditions, and their F₁ hybrids were used in this study. Seedlings of 36 doubled haploid lines, selected out of 96 according to their agronomic traits and the two parental genotypes were inoculated with eight races of yellow rust. The parental genotypes (‘Ghods’and‘9106’) were segregating for some of the races but their doubled haploid lines were either resistant or susceptible to them.‘Ghods’was susceptible to three of the races studied but three doubled haploid lines derived from it were resistant to them. Five selected doubled haploids from the‘9106’genotype and six from F₁ hybrid plants were resistant to all eight races tested. After further investigations in Iranian field conditions it was found that some of these lines can be used as donor genotypes for resistance to yellow rust in wheat breeding programmes. Use of these genotypes should be possible if the French yellow rust races used for selection also represent the dominant races in Iran. It can be concluded that anther culture provides an efficient method for fixing genes of resistance to yellow rust and desirable doubled haploids from F₁ plants can be derived.     

新疆阿勒泰地区和内蒙古乌拉特前旗抗列当向日葵品种(系)的鉴定

向日葵列当是向日葵生产中重要的寄生性杂草。新疆阿勒泰地区和内蒙古乌拉特前旗是国内向日葵列当发生的重灾区。为筛选并为抗列当育种工作提供优质抗性材料,从根本上防治向日葵列当,利用田间自然发生向日葵列当的田块,采用随机区组设计设置小区试验;通过寄生率、寄生程度2 个指标判定对列当的抗感性。于2012 年在新疆阿勒泰对56 个向日葵品种（系）,2013—2014 年在内蒙古乌拉特前旗分别对22 个品种（系）和20 个品种（系）,进行抗列当鉴定。结果表明：在新疆22 个油葵品（系）中‘陇葵杂1 号’、‘F08-1’、‘辽丰F53’、‘赤CY101’、‘S26’、‘MGS’、‘S31’等16 个品种,34 个食葵品种（系）中‘JK106’品种,表现为免疫;在内蒙古乌拉特前旗2013—2014 年24 个油葵品种（系）中,‘赤CY102’、‘F08-1’等2 个品种表现为免疫,‘MSG’、‘新葵杂5 号’、‘赤029×115R’、‘赤128A×116R’等4个品种（系）表现为高抗,而18 个食葵品种（系）中,没有免疫品种,只有‘JK103’和‘JK106’表现为抗列当,其余16 个品种（系）均表现为感病和高度感列当。其中油葵品种‘赤CY102’在新疆和内蒙古抗列当鉴定中均表现免疫。在2 个不同地区进行向日葵品种抗列当鉴定,新疆地区表现免疫和高抗的品种较内蒙古地区多,说明内蒙古乌拉特前旗列当生理小种级别高于新疆阿勒泰地区列当生理小种。另外,油葵品种对列当的抗性较食葵高。     

玉米大斑病广谱抗性外引自交系的发掘与抗病基因初步鉴定

从2014—2016年连续3年对43份来自美国、法国、俄罗斯和德国的玉米资源进行了抗大斑病人工接种鉴定, 筛选到高抗玉米大斑病材料7份, 抗病材料1份, 中抗材料6份, 抗性材料占鉴定总材料的比例为32.6%。利用F₂群体, 对7份高抗材料进行了大斑病抗性遗传分析, 抗感植株分离比例和适合性测验证明, 自交系A04、F02、F05和R01对大斑病的抗性可能是由一对显性基因控制的。抗谱分析表明, 自交系A04、F02、F05和R01携带的抗大斑病基因不同于Ht1、Ht2、Ht3和HtN, 可能是新的抗病基因。该研究结果可为今后我国玉米大斑病抗性种质的引进及改良提供重要参考。     

Inheritance of resistance to broomrape (Orobanche cumana Wallr.) race F in a sunflower line derived from wild sunflower species

Genetic resistance to broomrape (Orobanche cumana Wallr.) race F in sunflower line J1, derived from the wild perennial species Helianthusgrosseserratus Martens and Helianthus divaricatus L., has been reported to be controlled by dominant alleles at a single locus, Or6. However, deviations from this monogenic inheritance have been observed. The objective of the present study was to gain insight into the inheritance of resistance to broomrape race F in the sunflower line J1. F₁, F₂, F₃ and BC generations from crosses between J1 and three susceptible lines, P21, NR5 and HA821 were evaluated. F₁ hybrids showed both resistant (R) and moderately resistant (MR) plants, the latter having a maximum of five broomrape stalks per plant compared with >10 in the susceptible parents. This indicated incomplete dominance of the Or6 alleles. F₂ plants were classified as R, MR or susceptible (more than five broomrape stalks per plant). Three different segregation ratios were observed: 3 : 1, 13 : 3 and 15 : 1 (R + MR : S), suggesting the presence of a second gene, Or7, whose expression was influenced by the environment. A digenic model was confirmed, based on the evaluation of F_2:3 families.     

Race differentiation and search for sources of resistance to Rhynchosporium secalis in barley in Italy

Summary Barley in Italy has recently been seriously affected by Rhynchosporium secalis. The pathogenic variation of the fungus was studied and 17 races were differentiated on 13 barley cultivars carrying most of the currently known genes for resistance. RC 1, the most virulent and most frequent race, was virulent on 10 out of the 13 differentials and the remaining races proved to be less virulent variants of RC 1. Atlas (C.I. 4118), Atlas 46 (C.I. 7323) and Osiris (C.I. 1622) were the only three differentials resistant to all the analyzed single-spore isolates.Differential cultivars previously assumed to have identical resistance factors did not react in the same way to all the Italian races, thereby revealing either undisclosed differences in the genes described or the presence of additional unidentified ones.Our findings were compared with previous data about virulence of scald populations from different countries, on the basis of tests with common differentials: fundamental differences were found between the Italian population and those of other countries with regard to virulence patterns.The susceptible reactions to race RC 1 of most barley cultivars grown in Italy indicate the urgent need for resistance genes to be incorporated in the cultivated material. Seventy-one barley accessions, known as sources of resistance in different parts of the world, were screened for their behaviour to races RC 1 and RC 13. Twenty-two appeared resistant to both of them.     

玉米自交系对大斑病菌的抗性鉴定及抗性来源分析

玉米大斑病是一种严重影响玉米产量的病害,在全国各地多有发生。通过筛选抗病玉米自交系,选育优良抗病品种可以有效防止大斑病的发生。试验于2017-2018年,用田间人工接种大斑病混合菌的方法,对185份玉米种质进行了玉米大斑病抗性鉴定与评价,筛选出高抗自交系16份,其中自选系7份,并对玉米自选系抗病性来源进行分析,发现Y6和J1577等品系抗病性强且可以稳定遗传。     

Screening the Spanish Barley Core Collection for disease resistance

The Spanish Barley Core Collection comprises 159 landrace-derived inbred lines and 16 cultivars adapted to Southern European conditions. The collection was screened for resistance to powdery mildew ( Blumeria graminis ), scald ( Rhynchosporium secalis ), leaf rust ( Puccinia hordei ), net blotch ( Pyrenophora teres f. teres ), Barley yellow dwarf virus (BYDV) and Barley mild mosaic virus (BaMMV). Resistance to powdery mildew was outstanding, with 58 lines presenting mean overall resistance, among them seven landrace-derived lines resistant to all seven isolates tested. About 26% of the Spanish lines were resistant to scald. Resistance to leaf rust and to net blotch was scarce, though a few accessions showed resistance levels as good as the checks. Thirteen accessions (12 Spanish) were totally resistant to BaMMV and c. 20% of accessions showed moderate tolerance to BYDV. Landrace-derived lines from the Mediterranean Coast and Southern regions of Spain were the most resistant to powdery mildew and leaf rust, but the most susceptible to viruses. Potential sources of resistance might be preserved in some accessions subjected to selective pressure in the region of origin.     

Inheritance of resistance to two races of sunflower downy mildew (Plasmopara halstedii) in two Helianthus annuus L. lines

Sunflower downy mildew caused by Plasmopara halstedii is an important disease of sunflower capable of causing losses of more than 80% of production. Races 100, 300, 310, 330, 710, 703, 730 and770 of the fungus have been identified in Spain. Race 703, of high virulence, has been identified frequently in the northeast, while race 310 seems to occur over the south, the main sunflower growing region of the country. Oil sunflower lines RHA-274 and DM4 were studied for their resistance to races 310(RHA-274 and DM4) and 703 (DM4). In each cross, only one plant of the resistant parent was crossed to the inbred susceptible line HA-89 (or cmsHA-89).Plants from F₂ and backcross(BC₁F₁ to susceptible parent)generations were evaluated for fungal sporulation on true leaves and/or cotyledons. The resistant-to-susceptible ratios obtained in the F₂ and BC₁F₁ progenies from the crosses cmsHA-89 × RHA-274 and HA-89 × DM4suggested that one major gene in each line is responsible for resistance to race 703.The segregations of the progenies of the cross HA-89 × DM4 inoculated with race 703also fitted the ratios 1:1 and 3:1 (for BC₁F₁ and F₂, respectively)corresponding to control of resistance by a single dominant gene. In RHA-274, the gene for resistance to race 310 was designated Pl ₉, whereas Pl _v is tentatively proposed to designate the gene in DM4 responsible for resistance to races310 and 703. This revised version was published online in August 2006 with corrections to the Cover Date.     

玉米自交系生理指标与抗旱性及复水恢复能力的关系研究

【研究目的】为了评价不同玉米自交系的抗旱性，探究生理指标与抗旱性、恢复能力和综合抗旱能力之间的关系。【方法】本研究以19份自交系为材料，采用盆栽称重控水法对苗期玉米进行中度旱胁迫及复水，测定生物量、叶绿素含量、类胡萝卜素含量、Fv/Fm、脯氨酸含量和抗氧化酶活性对干旱和复水的响应。【结果】分析发现自交系‘郑8713’、‘郑63’和‘昌7-2’的抗旱性、恢复能力和综合抗旱能力均较强，自交系‘郑C112’、‘郑718’和‘郑6722’虽然抗旱性较弱，但是恢复能力和综合抗旱能力较强，自交系‘郑3733’、‘郑E846’和‘郑36’恢复能力较弱，但是抗旱能力和综合抗旱能力很强；同时发现类胡萝卜素与抗旱性之间呈现显著的相关性(P=0.503*)，POD抗氧化酶与复水后的恢复能力之间关系显著(P=0.421*)，Fv/Fm与综合抗旱性之间呈显著的相关性(P=-0.456*)，叶绿素含量与抗旱性(P=0.468*)和复水后的恢复能力(P=0.407*)之间均呈现显著的相关性。【结论】以上结果为培育抗旱型品种提供优良的种质资源，同时为玉米抗旱性、恢复能力及综合抗旱能力的筛选与鉴定提供一定的指导意义。     

小偃麦新种质CH7102抗条锈病特性的遗传分析

对衍生于普通小麦与八倍体小偃麦‘小偃7430’杂种后代的抗条锈病新种质CH7102进行抗性鉴定和遗传分析,明确其抗性来源及其遗传方式。采用条锈菌流行小种CYR31、CYR32对CH7102及其亲本进行苗期抗性评价;对CH7102分别与感病品种和已知抗性基因载体品系的杂交后代接种CYR32进行成株期抗条锈性遗传分析和等位性测验。CH7102具有与其抗病亲本‘小偃7430’和彭提卡偃麦草相似的侵染型,而所有的小麦亲本均感病,表明CH7102的抗性来自彭提卡偃麦草;CH7102与感病品种‘台长29’和‘绵阳11’杂交、回交,其F2、BC1、F2:3代的抗、感分离比分别符合3:1、1:1和1:2:1的单显性基因分离模式。而CH7102与已知抗性基因载体品系杂交F2代的抗感分离比为15:1。CH7102对条锈病的抗性来自彭提卡偃麦草,其抗性受1对显性核基因控制,而且与已知的抗CYR31、CYR32的抗性基因Yr5、Yr10、Yr15、Yr24/Yr26、Yr41不存在等位关系,属新的抗条锈病基因。     

以丽江新团黑谷为遗传背景的抗稻瘟病基因累加系的选育及其抗性鉴定

以丽江新团黑谷（LTH）近等基因系为亲本,构建了3个F₆重组自交系群体,以具鉴别能力的菌株进行抗稻瘟病筛选,共获得3组携带两个抗病基因的累加系5个,即：1) F-Kpib-3（Pi-k^p/Pi-b）,F-Kpib-6（Pi-k^p/Pi-b）;2) F-Kita²-7（Pi-k/Pi-ta²）,F-Kita2-9（Pi-k/Pi-ta²）;3) F-Kmita（Pi-km/Pi-ta）。基因组成相同的累加系抗性相同,它们的抗病频率均高于相应的近等单基因系,3组抗病频率分别达100.0%、91.7%和50.0%。这些累加系可用于稻瘟病菌致病型鉴定、田间稻瘟病菌致病性变异监测和作为抗病亲本用于抗病育种。     

水稻白叶枯病数量抗性座位定位及其小种专化性

用水稻白叶枯病3个毒力不同的菲律宾小种P2、P6和P9,对供体Lemont导入到特青背景的178个近等基因导入系群体,进行白叶枯病数量抗性座位(quantitative resistance loci, QRL)定位及其小种专化性研究。供试亲本Lemont感3个小种,特青中感P2和P9,感P6。导入系群体的病斑长度呈连续正态分布。共发现影响病斑长度的10个主效QRL     

Resistance to Sunflower Rust and its Inheritance in Wild Sunflower Species

Resistance to the prevailing races of sunflower rust, Puccinia hehanthi Schw., is lacking in the commercial hybrids (Helianthus annuus L.). The objective of this study was to identify new sources of resistance to the four North American rust races in wild Helianthus species, and to determine their mode of inheritance. Seventy-eight accessions of H. annuus L., H. argophyllus Torrey and Gray, and H. petiolans Nutt. were evaluated in the greenhouse. Resistance to races 1, 2, 3, and 4 was observed in 25, 28, 15, and 26% of the plants, respectively, and 10% of the plants were resistant to all four races. Seven accessions that had a high percentage of resistant plants to all the four races were selected and one resistant plant from each accession was crossed with susceptible inbred line HA89. Three to four F₁ plants resistant to all four races from each cross were backcrossed with HA89. F₁ plants from PI-413118 × HA89 and PI 413175 × HA89 were resistant to all four races. The PI 413023 × HA89 F₁ plants were 100 % resistant to races 3 and 4 and segregated in a 3: 1 resistant (R) to susceptible (S) ratio to races 1 and 2. The other four F₁ combinations segregated 3R: IS ratios to all four races. Bc₁F₁ progenies revealed that plants from PI 413048, PI 413037, PI 413038, and PI 413171 used in the crosses possessed two dominant genes in heterozygous condition for resistance to each of the four races, whereas plants from PI 413023 possessed two dominant genes in heterozygous condition for resistance to each of races 1 and 2, and one dominant resistance gene in homozygous condition for each of races 3 and 4. Plants from PI 413118 and PI 413175 carried a single dominant gene in homozygous condition for resistance against each of the four races.     

小麦‘西农291’成株期抗条锈病遗传分析

为明确‘西农291’抗条锈性的遗传基础。对‘西农291’在温室和田间进行多个小麦条锈菌小种的抗条锈鉴定;采用常规杂交方法,将‘西农291’分别与感病品种‘铭贤169’与AvS杂交,构建其F1、F2遗传群体,用小麦条锈菌小种CYR32进行温室抗条锈性鉴定、混合小种（CYR32:CYR33≈1:1）进行田间抗条锈性鉴定。结果表明,在温室条件下,‘西农291’在苗期对条锈菌CYR32与CYR33表现高度感病、成株期对CYR32、CYR33、Su11-4及Su11-7表现高度抗条锈性;田间混合小种接种诱发发病（陕西杨凌）和自然发病（甘肃天水）抗条锈性鉴定均表明‘西农291’在成株期高度抗条锈病。群体抗条锈性鉴定结果表明‘西农291’与感病品种铭贤169和AvS杂交的F2群体的抗:感分离比例均符合3R:1S的理论比例。以上结果说明‘西农291’具有非小种专化性的、广谱抗性的成株期抗条锈性;对CYR32的成株抗条锈性受1对显性基因控制。