The use of even-chain alkanes sprayed onto herbage as rate of passage markers in goats

An experiment was conducted with Saanen goats fed fresh grass ad libitum to compare ⁵¹Cr-mordanted fibre and even-chain alkanes sprayed onto either grass leaves or stems to estimate faecal output, total mean retention time (TMRT) and parameters obtained from faecal marker concentration curves, such as k₁ (slow rate of passage), k₂ (fast rate of passage) and transit time (TT). ⁵¹Cr-mordanted grass showed the lowest fractional rates of passage (k₁ and k₂) and hence the largest value of TMRT. There were not significant (P > 0.05) differences between even-chain alkanes sprayed onto leaves or stems for k₂, TT and TMRT, but k₁ estimates were higher (P < 0.05) for stems than for sprayed leaves. Despite the marker used, TMRT values were negatively correlated with the level of dry matter intake (r = − 0.81, − 0.80 and − 0.80 for ⁵¹Cr-mordanted fibre and even-chain alkanes adsorbed onto leaves or stems, respectively). Average faecal outputs estimated from faecal concentrations of ⁵¹Cr-mordanted fibre and even-chain alkanes were not different from the actual outputs but there were differences between markers in the accuracy of estimation. The highest mean square prediction error (MSPE) and the poorest correlation between observed and estimated faecal output values corresponded to even-chain alkanes adsorbed onto stems. Values estimated using ⁵¹Cr-mordanted fibre and even-chain alkanes adsorbed onto leaves were significantly correlated with faecal outputs (r = 0.94 and r = 0.92, respectively), with MSPE being greater for the latter marker.     

Genetic variability and virulence among Verticillium albo-atrum isolates from hop

Verticillium wilt, caused by Verticillium albo-atrum or V. dahliae, is an important disease of many worldwide crop species. In Europe, V. albo-atrum isolates infecting hop express different levels of virulence, inducing mild or lethal disease syndromes, and it is therefore an attractive model for studying the virulence of this pathogen. In this work, eleven amplified fragment length polymorphism (AFLP) primer combinations were used to analyze genetic variability among 55 V. albo-atrum hop isolates from four European hop growing regions, as well as isolates from other hosts and V. dahliae isolates. Cluster analysis divided V. albo-atrum and V. dahliae isolates into two well-separated groups. Within the V. dahliae cluster, isolates were separated without host specific grouping, although no host adapted isolates were included. In V. albo-atrum, the alfalfa isolates were distinct from isolates of other hosts, where a high association with virulence was observed in hop and tomato isolates. All lethal hop isolates were genetically different from mild hop isolates. The lethal hop isolates from England and Slovenia expressed the same virulence phenotype, although they showed a different AFLP pattern. The mild hop isolates formed two subgroups, to which isolates clustered irrespective of geographical location. These data suggest multiple origins of V. albo-atrum hop isolates, and the possible appearance of new virulent isolates in the future in other hop growing regions.     

Application of bovine microsatellite markers for genetic diversity analysis of European bison (Bison bonasus)

In this study, the cross‐amplification of a commercial multiplex set of 11 cattle (Bos taurus) microsatellites was tested on a panel of 35 European bison (Bison bonasus) individuals. After polymerase chain reaction optimization, all loci cross‐amplified successfully in investigated bisons. Number of alleles and observed and expected heterozygosity per locus are in the range of 2–4, 0.086–0.629 and 0.288–0.621 respectively. The availability of a heterologous set of multiplexed microsatellite markers derived from cattle opens an avenue for collecting profound genetic data for efficient conservation management strategies of the European bison.     

桃果肉颜色、果皮茸毛和花粉育性性状的分子标记

 以91-42-51 ×瑞光2号的杂交后代共48个单株为试材, 采用集群分离分析法(BSA) , 对桃果实的有毛/无毛、白肉/黄肉以及无花粉/有花粉3 个性状进行了分子标记研究。研究获得SSR 标记UDP96-018 (300 bp) 与有毛性状连锁, 遗传距离4.5 cM, SSR标记UDP98-407 (680 bp) 与白肉性状连锁, 遗传距离为2.2 cM; 根据拟南芥雄性不育序列标记设计的引物扩增出的两个片段NNJ-I (600 bp ) 和NNJ-I (900 bp) 与桃无花粉性状之间的遗传距离为0 cM。这些标记的获得为桃分子标记辅助育种提供了有效的筛选手段。     

Molecular assessment of polymorphism among local Jordanian genotypes of the common fig (Ficus carica L.)

This research was conducted to assess polymorphism among local genotypes of common fig available in Jordan (one of countries of origin). Leaf samples were collected in spring for DNA isolation from 20 different local genotypes (5 cultivars and 15 landraces). Two more wild types and one foreign cultivar were included. The genotypes were assessed using the randomly amplified polymorphic DNA (RAPD) technique. Six of the 19 screened primers showed reproducible polymeric profiles. Out of 62 amplified bands, 48 were polymorphic (77%). They generated 1104 data entries (591 for present and 513 for absent bands). After determining Jaccard similarity index, some genotypes showed high genetic similarity (90% between F20 and F22), while other were less similar (3–18% between F11 and all other genotypes). Moreover, the primers were evaluated for their discriminating power, where primer RAPD06 showed the weakest power (0.431), while highest values of 0.989 and 0.996 were achieved for primers RAPD02 and RAPD13, respectively.     

朝鲜鹌鹑遗传多样性微卫星标记分析

选用鹌鹑上的12个微卫星位点,对随机选取朝鲜鹌鹑的40个个体进行多态性检测,共检测到55个等位基因,每个座位平均等位基因数为4.583个。该群体平均多态信息含量和平均杂合度分别为0.6945和0.7111,表明朝鲜鹌鹑属多态性较丰富的群体。     

Microsatellite markers based assessment of genetic diversity in Iranian olive (Olea europaea L.) collections

To study the genetic variation in Iranian olive collections and some foreign olive cultivars, 47 accessions of 18 local cultivars from 6 olive collections of Iran (Roudbar, Zanjan, Ahvaz, Dezful, Kazeroon and Shiraz), were analyzed along with 30 imported cultivars using 16 microsatellite primer pairs. All the used microsatellite loci revealed polymorphism in the studied genotypes, except GAPU14 and GAPU113 markers. Fourteen microsatellite primers amplified 126 polymorphic alleles in the 87 selected olive accessions. The average number of alleles per locus was 9, ranging from 3 to 14. Polymorphic information content (PIC) was 0.85. The genetic similarity based on Jaccard coefficient ranged from 0.15 to 1. The genetic relationships among accessions were investigated using cluster analysis and principal component analysis (PCA). Most of the accessions with the same name were grouped together; some exceptions were also observed. As expected, close relationship was observed among accessions within same cultivar. Most of the Iranian olive accessions were clustered to a main distinct group. Two-dimensional scatter plot of principal component analysis revealed a clear separation of most of the Iranian olives from Syrian and other introduced cultivars. These suggest that Iranian cultivars have different origin related to West Mediterranean basin cultivars and have evolved independently from the others. Between and within Iranian and foreign cultivars (cultivars including three or more accessions) genetic diversity was analyzed using analysis of molecular variance (AMOVA). AMOVA revealed higher within cultivar genetic variation (62.76%) as compare to that between cultivar variations (37.24%). The intra- and inter-cultivar variance tested by permutation test showed significant genetic variation at both levels. The high level within cultivar genetic variance could be due to mislabeling and presence of homonyms in cultivars produced by vegetative propagation from original plants.     

Molecular characterization and genetic relationship among almond cultivars assessed by RAPD and SSR markers

RAPDs and SSRs were used to study the genetic diversity of Iranian almond cultivars and their relationship to important foreign cultivars and three related species. Eight unidentified almond Shahrodi cultivars and three wild almonds (Prunus communis, Prunus orientalis and Prunus scoparia) were also included. Of the primers tested, 42 (out of 80) RAPD and 18 (out of 26) SSR primers were selected for their reproducibility and high polymorphism. A total of 664 polymorphic RAPD bands were detected out of 729 bands. The number of presumed alleles revealed by the SSR analysis ranged from 3 to 10 alleles per locus with a mean value of 6.64 alleles per locus. Both techniques discriminated the genotypes very effectively, but only RAPDs were able to discriminate the cultivars Monagha and Sefied. Results demonstrated an extensive genetic variability within the tested cultivars as well as the value of SSR markers developed in peach for characterization of almond and related species of Prunus. Dice similarity coefficient was calculated for all pair wise comparisons and was used to construct a UPGMA dendrogram. For both markers a high similarity in dendrogram topologies was obtained although some differences were observed. All dendrograms, including that obtained by the combined use of both the marker data, depicted the phenetic relationships among the cultivars and species, depending upon their geographic region and/or pedigree information. Almond cultivars clustered with accession of P. communis showing their close relationship. P. orientalis and P. scoparia were clustered out of the rest of P. dulcis.     

Detecting<Emphasis Type="Italic">Orobanche</Emphasis> species by using cpDNA diagnostic markers

Some species of the genusOrobanche are among the most devastating parasitic weeds, causing extensive damage in agricultural fields. Considering the difficult control due to seed longevity in the soil, small seed size, high fecundity and a subterranean phase that allows them to parasitize the host before they emerge and become evident, the development of diagnostic markers is highly recommended. In our study we identified potential molecular diagnostic markers from the plastid genome in order to distinguish among the most importantOrobanche species attacking crops in Andalusia, the southern region of the Iberian Peninsula. The study has consideredO. crenata, O ramosa andO. cumana causing serious losses in legumes, solanaceous crops and sunflower fields, respectively, andO. minor that, although abundant in Andalusia, has to our knowledge not yet been found parasitizing agricultural hosts. We amplified a non-coding region from the plastid genome, studied sequence differences among the amplified fragments and digested those of the same length with selected restriction enzymes. Here, we propose a molecular protocol to distinguish the main parasitic plants in crop fields of southern Spain. Different applications such as identification ofOrobanche seeds in soil or crop seed lots are discussed in order to offer right crop recommendations or to prevent new infestation of parasite-free fields. Recommendations for further development of these diagnostic markers are also considered. http://www.phytoparasitica.org posting Jan. 15, 2007.     

Bulked Segregant Analysis to Detect QTL Related to Heat Tolerance in Rice （Oryza sativa L.） Using SSR Markers

The study was undertaken to assess the genetic effect of quantitative trait loci （QTLs） conferring heat tolerance at flowering stage in rice. A population consisting of 279 F2 individuals from the cross between 996, a heat tolerant cultivar and 4628, a heat-sensitive cultivar, was analyzed for their segregation pattern of the difference of seed set rate under optimal temperature condition and high temperature condition. The difference of seed set rate under optimal temperature condition and high temperature condition showed normal distribution, indicating the polygenic control over the trait. To identify main effect of QTL for heat tolerance, the parents were surveyed with 200 primer pairs of simple sequence repeats （SSR）. The parental survey revealed 30% polymorphism between parents. In order to detect the main QTL association with heat tolerance, a strategy of combining the DNA pooling from selected segregants and genotyping was adopted. The association of putative markers identified based on DNA pooling from selected segregants was established by single marker analysis （SMA）. The results of SMA revealed that SSR markers, RM3735 on chromosome 4 and RM3586 on chromosome 3 showed significant association with heat tolerance respectively, accounted for 17 and 3% of the total variation respectively. The heat tolerance during flowering stage in rice was controlled by multiple gene. The SSR markers, RM3735 on chromosome 4 and RM3586 on chromosome 3 showed significant association with heat tolerance respectively, accounted for 17 and 3% of the total variation respectively. The two genetic loci, especially for RM3735 on chromosome 4, can be used in marker-assistant-selected method in heat tolerance breeding in rice.