Selection of Diploid Nematode-Resistant Sugar Beet from Monosomic Addition Lines

Monosomic sugar beet/wild beet addition lines (2n = 19) with full resistance against the beet cyst nematode have been characterized in different ways. Within the B. procumbens and B. webbiana addition lines three groups could be classified according to their isozymes pattern, growth habit, transmission rate, and resistance level. It is assumed that B. procumbens and B. webbiana each possess three different chromosomes which carry genes for nematode resistance. In the offspring of the addition lines diploid translocation types appear at very low frequencies, Isozyme pattern or growth type of the resistant plants were used for selecting diploid types in the offspring of monosomic addition lines. Effective selection could be made in progenies of susceptible sugar beets pollinated by addition lines because the pollen transmission of the alien chromosome is very low. Using these methods 7 nematode-resistant sugar beet lines could be selected. The transmission rates of the resistance gene ranged from 70.6% to 100%. Threw heterozygous progenies showed a 1:1 segregation indicating monogenic dominant inheritance of resistance. The level of resistance was as high as in the addition lines.     

First report of leaf rust pathotypes virulent to highly effective Lr-genes transferred from Agropyron species to bread wheat

The gene pool of effective sources of leaf rust resistance used in the breeding of wheat (Triticum aestivum L.) includes several species of the genus Agropyron. The genes deriving therefrom (Lr 19, 19d, 29, Agⁱ1, Agⁱ2, 38) are highly effective to pathotypes of Puccinia recondita Rob. ex Desm. In the Saratov and Orenbhurg districts of Russia, however, pathotypes virulent to these genes have been discovered. These pathotypes are virulent to Saratov-bred cultivars carrying Lr 19, to ‘Indis’ (Lr 19d) and RL 6097 (Lr 38). The distribution of virulence on the ‘Thatcher’ near-isogenic lines with different Lr genes shows that most of the Lr genes tested are susceptible to these new pathotypes of P. recondita, but the Lr genes Lr 9, 23, 24, 26 were exceptions. The inoculation of Mexican bread wheat cultivars, which carry widespread Lr gene combinations, by these pathotypes disclosed different infection types. Out of 10 Lr-gene combinations, four were highly effective; namely the combinations Lr 13 + 26, Lr 26 +?, Lr 23+26 and Lr 23+26+34.     

Non-homoeologous wheat-rye chromosomal translocations conferring resistance to greenbug

Summary C-banding andin situ hybridization were used to determine the chromosomal constitution of the greenbug-resistant germplasm GRS 1204. The results showed that this line had the radiation-induced non-homoeologous wheat-rye translocation chromosomes T2AS-1RS·1RL and T2AL·2AS-1RS. C-banding analysis further revealed the presence of a wheat-Agropyron elongatum translocation chromosome T1BL·1BS-3Ae#1L in line GRS 1204, that was derived from Teewon. The greenbug resistance of line GRS 1204 is similar to that of line GRS 1201 that was earlier shown to have the greenbug resistance geneGb6 located on the 1RS arm of the wheat-rye translocation chromosome T1AL·1RS. BecauseGb6 in line GRS 1204 is present on one of the non-homoeologous translocation chromosomes, agronomically line GRS 1201 should be the better adapted source ofGb6 resistance and be used in cultivar improvement.     

Nematode Resistance Derived from Wild Beet and its Meiotic Stability in Sugar Beet

Three different karyotypes of sugar beet with resistance against the beet cyst nematode (Heterodera schachtii) have been investigated. These comprised monosomic addition lines (2n = 19) with one complete chromosome from B. patellarris or B. procumbens, one line with a chromosomal fragment added to the normal sugar beet chromosome complement (2n =18 + fragment) and one diploid line (2n = 18). The fragment originated from a B. procumbens chromosome since during meiosis it formed a univalem. It carries the gene for nematode resistance. Meiotic disturbances like univalems. laggards, anaphase I bridges, fragments and micronuclei were observed in all resistant genotypes. These may result in an exclusion of the chromosome fragment carrying the resistance from the rest of the genome. In the diploid resistant line, a chromosome with a translocation could be distinguished from the other B. vulgaris chromosomes. Meiotic irregularities also appeared in diploid resistant types and are one main reason for low transmission of the resistance. Tin-relationship between meiotic stability and the transmission rate of the resistance gene is discussed.     

利用1RS特异标记和染色体原位杂交技术鉴定小麦1BL·1RS易位系

以小麦-黑麦1BL·1RS易位系(Kavkaz、山农030-1)、1AL·1RS易位系(Amigo)、荆州黑麦、八倍体小黑麦劲松49、1R-7R二体异附加系以及普通小麦中国春、辉县红、铭贤169、Chancellor等为材料,对65个黑麦1RS特异标记进行鉴定,从中筛选出8个稳定的标记,即NOR-1、SECA2/SECA3、SCSS30.2、Sec1Gene、Sec1Pro、ω-Sec-P1/P2、ω-Sec-P3/P4和IB-267,可用于检测1AL·1RS易位系或1BL·1RS易位系;另外3个特异标记O-SEC5′-A/O-SEC3′-R、IAG95-1和SCM-9可用于区别1RS来源不同的1AL·1RS和1BL·1RS易位系。利用这11个标记和染色体原位杂交技术对40份山东省近年育成小麦品种(系)进行检测,发现潍麦8号、鲁麦14、济宁13、山农664、山农优麦3号和烟农25为1BL·1RS易位系,而且是1RS的整臂易位系,未检测到1AL·1RS易位系和其他易位类型。     

基于RNA-seq的百萨偃麦草染色体特异分子标记开发与应用

【目的】百萨偃麦草（Thinopyrum bessarabicum Löve, 2n = 2x = 14, JJ或E^bE^b）是小麦改良的重要亲缘物种,开发染色体特异分子标记对于加快其有利基因向小麦中的转移和应用有重要意义。【方法】利用百萨偃麦草分蘖期叶片RNA-seq获得的EST序列与节节麦D基因组序列进行比对,鉴定出4 957条没有相似性的序列作为筛选百萨偃麦草特异序列的基础序列。从这些基础序列中随机选择部分序列设计EST-PCR引物507对,通过在普通小麦中国春、百萨偃麦草和中国春-百萨偃麦草双二倍体中的扩增分析,筛选出百萨偃麦草基因组特异标记,然后在已经选育出的8个小麦-百萨偃麦草异染色体系中进行染色体定位,并探讨这些标记在小麦染色体工程中的应用潜力;根据谷类作物的共线性,以百萨偃麦草EST序列设计共线性引物100对,并比较这些引物的扩增和定位结果。【结果】在开发的507对引物中,204对（40.2%）在百萨偃麦草和中国春-百萨偃麦草双二倍体中具有特异扩增,多态率远高于利用小麦（12%）和百萨偃麦草（14%）EST设计的234对共线性引物产生的多态率,建立了高效开发小麦亲缘物种特异标记的新方法;利用8个中国春-百萨偃麦草异染色体系,共定位了198个百萨偃麦草特异标记,分别位于染色体1J（31）、2JS（15）、2JL（26）、3JS（20）、4JS（12）、4JL（12）、5J（27）、6JS（13）、6JL（22）和7JS（20）,其中189个是根据百萨偃麦草转录组序列设计;利用定位于1J和6J的特异标记确定了4个易位系的染色体身份,其中1个涉及1J的大片段易位,2个涉及6JS的不同区段易位,1个为小片段中间插入易位;利用这些易位系,将30个1J和12个6J特异标记分别定位于2个物理区段。【结论】通过RNA-seq结合与小麦基因组序列比对可以获得小麦亲缘物种相对特异的EST序列并据此开发引物,建立了开发外源染色体特异标记的新方法,开发的标记可应用于小麦异易位系鉴定和缺失物理图谱的绘制。     

Cumulative and interaction effects of prolamin allelic variation and of 1BL/1RS translocation on flour quality in bread wheat

The allelic variation of prolamin loci was studied in three F₂ progenies from three crosses between the 1BL/1RS cultivar Triana and Yécora Rojo, Pavón and Florence Aurora, cultivars without the translocation. According to the 1:2:1 theoretical proportions observed in the allelic variants of the Glu-B3/Gli-B1 loci of the parent without the translocation, the inheritance as a block of the rye chromosome arm was confirmed. A group of F₃-F₄ recombinant lines, developed from these crosses was evaluated using the SDS-sedimentation test and the mixograph and alveograph tests. The presence of the 1BL/1RS translocation was not associated with significantly lower grain protein content values or with the optimum mixing time in the mixograph of the genotypes. The effect of the 1BL/1RS translocation on most of the quality parameters was highly dependent on the genetic pool. Significant increases in gluten strength and better mixing properties associated with the presence of some alleles of the Glu-A1, Glu-A3/ Gli-A1 and Gli-D2 loci were detected. The additivity and the interaction of prolamin gene effects with the rye translocation in the 1BL/1RS lines and its possible use in plant breeding are discussed. This revised version was published online in July 2006 with corrections to the Cover Date.