scholarly journals Genetic Diversity of the Pm3 Powdery Mildew Resistance Alleles in Wheat Gene Bank Accessions as Assessed by Molecular Markers

Diversity ◽  
2010 ◽  
Vol 2 (5) ◽  
pp. 768-786 ◽  
Author(s):  
Navreet K. Bhullar ◽  
Michael Mackay ◽  
Beat Keller
Plants ◽  
2021 ◽  
Vol 10 (10) ◽  
pp. 1988
Author(s):  
Antonín Dreiseitl ◽  
Zdeněk Nesvadba

The main problems of crop gene banks comprise heterogeneity of accessions, resulting from mechanical admixtures or out-crossing during their multiplication, and especially the mislabeling of accessions. These discrepancies can adversely affect the results of many expensive research and breeding projects that are based on the use of gene bank resources. To tackle these problems, 860 single-plant progenies (SPPs) of 172 accessions of the Czech winter barley core collection were grown and tested with a set of 53 isolates representing the global virulence/avirulence diversity of powdery mildew. Seventy-one resistance phenotypes encompassed the diversity of known specific resistances and their combinations. Based on testing groups of five SPPs, 94 accessions had one phenotype found in all five SPPs (homogeneous accessions), whereas in 78 accessions (45.3%) more than one phenotype was identified (heterogeneous accessions). In three varieties, specific resistances against the whole set of isolates were detected, but due to high adaptability of the pathogen, they are not recommended for breeding resistant cultivars. Selected SPPs were integrated in the gene bank and are now a reliable source of genotypically pure seed with defined powdery mildew resistance genes that can be used by breeders and researchers. The results obtained can be used to verify authenticity of accession genotype and pedigree, particularly for older varieties for which no other original criteria are available.


Plants ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 1227
Author(s):  
Monika Höfer ◽  
Henryk Flachowsky ◽  
Susan Schröpfer ◽  
Andreas Peil

A set of 680 apple cultivars from the Fruit Gene bank in Dresden Pillnitz was evaluated for the incidence of powdery mildew and scab in two consecutive years. The incidence of both scab and powdery mildew increased significantly in the second year. Sixty and 43 cultivars with very low incidence in both years of scab and powdery mildew, respectively, were analysed with molecular markers linked to known resistance genes. Thirty-five cultivars were identified to express alleles or combinations of alleles linked to Rvi2, Rvi4, Rvi6, Rvi13, Rvi14, or Rvi17. Twenty of them, modern as well as a few traditional cultivars known before the introduction or Rvi6 from Malus floribunda 821, amplified the 159 bp fragment of marker CH_Vf1 that is linked to Rvi6. Alleles linked to Pl1, Pld, or Plm were expressed from five cultivars resistant to powdery mildew. Eleven cultivars were identified to have very low susceptibility to both powdery mildew and scab. The information on resistance/susceptibility of fruit genetic resources towards economically important diseases is important for breeding and for replanting traditional cultivars. Furthermore, our work provides a well-defined basis for the discovery of undescribed, new scab, and powdery mildew resistance.


2021 ◽  
Author(s):  
Mateusz Maksymilian Dyda ◽  
Mirosław Tyrka ◽  
Gabriela Gołębiowska ◽  
Marcin Rapacz ◽  
Maria Wędzony

Abstract Combining to tolerance to biotic and abiotic stresses is important target for modern triticale breeding. Cultivation of varieties resistant to fungal pathogens is economically and environmentally important and may lead to reducing of the use of fungicides. Molecular markers are necessary for accumulation of advantageous alleles in the best genotypes by means of marker-assisted and genomic selection approaches. In present research, QTL regions associated with the powdery mildew resistance at adult plant stage were evaluated in order to provide the effective selection tools. Testing of DH population in multiple environments under natural infestation revealed 20 QTL on wheat (4A, 3B, 4B) and rye (2R, 4R, 5R, 6R) chromosomes. Regions explained 8.1% - 29.3% of phenotypic variation depending of the trait, localization and year of the experiment. Main QTL with effect exceeding 15% were found on chromosomes 3B, 4B, 2R, 5R and 6R. QTL and candidate genes located on chromosomes 4B, 2R, 5R and 6R are so far reported for the first time as regions associated with PM resistance in the adult triticale plants. Additionally, within all QTL, 21 candidate genes associated with the PM resistance were revealed. Predicted function of protein encoded by these genes include triggering a defense system which restricts the pathogen growth, enzyme activity, regulation of hormone-activated pathways, transcriptional corepressor complex and cell wall construction. Availability of QTL, molecular markers together with candidate genes linked with the powdery mildew resistance can be validated on triticale lines and varieties and then, used in MAS to improve modern breeding.


Author(s):  
Doan Thi Thuy Linh ◽  
Tran Thi Truong ◽  
Chu Hoang Ha ◽  
Le Van Son

Powdery mildew disease, one of the major diseases of soybean in Vietnam was caused by Microsphaera diffusa. SSR (Simple sequence repeats) marker, because of their co-dominance, polymorphic and stability have been wildely used to measure genetic diversity in crop. In the present study, genetic basis of 36 soybean genotypes varying in powdery mildew resistance was studied using 14 SSR markers. A total of 61 alleles with an average of 4,36 allele/locus, which indicated hight genetic diversity of the studied genotypes. PIC value of each marker ranged from 0 (Sat_396, Satt183, Sat_298) to 0,711 (Sat_224) with an average of 0.364 which shown high genetic diverrsity among the studied genotypes. At genetic similarity coefficient of 0.75, 36 soybean genotypes divided into 8 distint groups. Group 1 and group 2 included 21/25 genotypes which was resistant to powdery mildew. Groups 1, 2, 4, 5 and 8 include powdery mildew resistance genotypes.  


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