is a species hybrid that causes a destructive root and collar rot disease of alders throughout Europe. Its subspecies,
alni (Paa), P. alni
can be distinguished on the basis of phenotypic and genotypic traits. In this study, we report evidence of an unusual genomic combination of two subspecies occurring in two
isolates from Hungary. These isolates, which had previously been identified as
using hybrid-specific PCR primers and morphological traits, exhibited a mitochondrial DNA restriction pattern identical to that of
However, RAPD patterns and isozyme profiles of nuclear genes encoding glucose-phosphate isomerase (Gpi) and malate dehydrogenase (Mdh) of the two atypical isolates were identical to those found in all
isolates. Isozyme analysis also revealed a novel allele at the putative
isolates. The atypical
isolates have likely emerged as a result of hybridization events in the
Chlorophyll content is positively correlated with photosynthetic rate. However, little is known about the genetic correlation between grain yield and chlorophyll content in the same wheat mapping population. The primary goal of the study was to detect the genetic basis of grain yield and chlorophyll content and their possible roles in the genetic improvement of grain yield in wheat. Here, quantitative trait loci (QTLs) for grain yield and chlorophyll content were studied using a set of 168 doubled haploid (DH) lines derived from a cross between two elite Chinese wheat cultivars, Huapei 3×Yumai 57. The DH population and parents were evaluated for grain yield and chlorophyll content in three environments. A total of 11 additive QTLs and 6 pairs of epistatic QTLs were detected for grain yield and chlorophyll content. Loci, such as
on chromosomes (e.g. 2D, 4A, and 5D) simultaneously controling grain yield and chlorophyll content, showed tight linkages or pleiotropisms. Three novel major QTLs,
, closely linked with the PCR marker
on chromosome 5D, accounted for 10.32%, 12.95%, and 23.29% of the phenotypic variance, respectively. The favorable alleles came from Yumai 57.
Authors:T. Efremova, N. Trubacheeva, E. Chumanova, E. Badaeva, L. Rosseeva, V. Arbuzova and L. Pershina
As a result of crossing substituted lines Saratovskaya 29 (S29) 5R(5A) and S29 5R(5D) with line L2075 (T1RS·1BL), two homozygous wheat-rye lines were obtained in the F7 generation and identified as T5AS·5RL + T1RS·1BL and 5R(5D) + T1RS·1BL, respectively. The rye chromosomes yare of different origins: 5R originated from spring rye Onohoskaya and 1RS from winter rye Saratovskaya 5. A new Robertsonian translocation was obtained where the 5RL arm was translocated to the short arm of wheat chromosome 5A, resulting in the T5AS·5RL translocation chromosome. Two translocations, T5AS·5RL and T1RS·1BL, and one chromosome substitution, 5R(5D), were identified and confirmed to be compensating on the basis of genomic in situ hybridisation, C-banding and 1RS- and 5R-specific PCR markers. Evaluation of resistance to fungal diseases revealed that homozygous T5AS·5RL + T1RS·1BL and 5R(5D) + T1RS·1BL lines are resistant to leaf rust and powdery mildew.
Wheat yellow rust resistance gene Yr17 was originated from the wheat-Aegilops ventricosa introgression, and still effective on the adult plant in Southern China. The previous studies located the gene Yr17 on the translocation of 2NS-2AS using the molecular and cytological markers. In the present study, we screened new PCR-based markers to map the gene Yr17 region from the investigation of a segregating 120 F2 population. All markers including four EST-PCR markers, a SCAR (sequence characterized amplified region) and a PLUG (PCR based landmark unique gene) marker specific to Yr17 gene were mapped on the chromosome 2AS, and located on the chromosomal deletion bin 2AS5-0.8–1.00 region. Based on the wheat-rice collinearity, we found that the sequences of the Yr17 gene linked markers were comparatively matched at rice chromosome 4 and chromosome 7. However, the identified closely linked genomic sequence of Yr17 gene is most likely collinear with genomic region of rice chromosome 4. The newly produced PCR based markers closely linked to Yr17 gene will be useful for the marker-assisted selection in wheat breeding for rust resistance.
Authors:F. Nocente, L. Sereni, A. Matere and M. Pasquini
Regular disease monitoring is currently carried out in the most important Italian wheat growing areas. In 2007–08 stem rust was absent in all locations tested except Montelibretti (Rome, Central Italy), where two common wheat varieties “Arsenal” and “Compair” had stem rust infections. Two stem rust pathotypes were identified by testing in the greenhouse a set of differential lines/varieties carrying known genes for resistance to Puccinia graminis. These pathotypes corresponded to races MSK and PTK on the basis of the North American classification system. Genes Sr24 and Sr25 (both derived from Thinopyrum ponticum) and Sr31 (from Secale cereale), were resistant to the Italian pathotypes, and the lines carrying Sr38 (from Triticum ventricosum) were susceptible.Tests were carried out to determine the seedling stem rust response of durum and common wheat cultivars grown in Italy. Many durum wheat genotypes were resistant to MSK and PTK, while several common wheats were susceptible. The different response of the two species could be due to the source (common wheat) of stem rust inoculum. Molecular PCR markers, linked to Sr24, Sr25, Sr31 and Sr38, were used to detect their presence/absence in the genetic background of the durum and common wheat cultivars. The presence of Sr31 was shown in only two common wheat cultivars (“Colledoro” and “Sollario”), while several genotypes carried Sr38. No common wheat genotype was positive (to PCR analysis) for the presence of Sr24 or Sr25 genes, whereas no durum wheat was positive for the presence of Sr24, Sr25, Sr31 or Sr38.
Talbert, L. E., Bruckner, P. L., Smith, L. Y., Sears, R., Martin, T. J. 1996: Development of PCRmarkers linked to resistance to wheat streak mosaic virus in wheat. Theor. Appl. Genet. , 93 , 463-467.
Development of PCRmarkers
Authors:I. Cernák, J. Taller, I. Wolf, E. Fehér, G. Babinszky, Z. Alföldi, G. Csanádi and Z. Polgár
Flis, B., Hennig, J., Strzelczyk-Żyta, D., Gebhardt, C., Marczewski, W. (2005) The
for extreme resistant to
Y maps to potato chromosome XII and is diagnosed by PCRmarker GP122