Browsing by Subject "Secale cereale"

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Appreciable genetic correlation between inbred lines and testcrosses facilitates breeding for resistance to Fusarium head blight in hybrid rye (Secale cereale)
(2021) Miedaner, Thomas; Rose, Marvin; Overbeck, Franziska; Koch, Silvia; Gruner, Paul; Eifler, Jakob
Hybrid breeding is based on selection of inbred lines in early generations. A sufficient genetic correlation between inbred lines and testcrosses is, however, the prerequisite for a higher selection gain in the hybrids. Therefore, we investigated this crucial parameter for Fusarium head blight (FHB) resistance on 60 inbred lines each of the heterotic groups Petkus and Carsten and their corresponding crosses with two testers each at four (inbred lines) or six (testcrosses) environments (location × year combinations). FHB severity measured as percentage of infected spikelets per plot was used as resistance trait, and a correction was made by using flowering time as covariate. Variances for genotype and genotype–environment interaction were high, and the heritability was estimated .84 and .74 for the line per se performance (Petkus and Carsten) and .71 and .78 for the general combining ability (GCA). For both inbred lines and testcrosses, negative correlations with plant height were found ranging from −.20 to −.51. FHB severity was considerably higher for the inbred lines than for the testcrosses. Genetic variance was lower for testcrosses, and dominance effects of the testers and heterosis may be key factors reducing the general infection level of three‐way hybrids. The effect of the tester (i.e., difference between testers) was very small and only significant for the Carsten group. The variance for specific combining ability (SCA) was very small, too. This, and high genetic correlations between line per se and GCA (r = .82 for Petkus and r = .72 for Carsten), does allow or even favour the selection based on line per se performance. Still, in the last generation before the official trials, testcrosses should also be tested for FHB resistance and mycotoxin contents to reliably improve food and feed quality in rye.
Ergot infection in winter rye hybrids shows differential contribution of male and female genotypes and environment
(2020) Kodisch, Anna; Wilde, Peer; Schmiedchen, Brigitta; Fromme, Franz-Joachim; Rodemann, Bernd; Tratwal, Anna; Oberforster, Michael; Wieser, Franz; Schiemann, Andrea; Jørgensen, Lise Nistrup; Miedaner, Thomas
Contamination of ergot (Claviceps purpurea) in grains continues to be a problem in outcrossing plants like rye, especially in years of favorable infection (cold, rainy) conditions. The problem is not the yield loss, but the contamination of the grains by toxic alkaloids leading to strict critical values within the European Union. This study was conducted to (1) partition the variation of genotype, inoculation treatments and environment for ergot infection of 12 winter rye genotypes, (2) the effect of varying proportions of a non-adapted restorer gene on ergot, and to (3) reveal within the genotype the relative importance of male pollen fertility and female receptivity on the ergot reaction of single crosses bearing different restorer genes. In total, 12 rye genotypes and two factorial crossing designs with each of five female and four male lines differing in their restorer genes were tested by artificial infection in up to 16 environments in four European countries. High and significant genotypic variation regarding the ergot severity and pollen-fertility restoration were observed. Furthermore significant general combining ability and specific combining ability variances and interactions with environment were obtained. The pollen-fertility restoration of the male had by far the highest importance for ergot severity, the female component, however, also revealed a significant effect. In conclusion, selecting for superior restoration ability is the most promising way on the short term, but there are also possibilities to improve the maternal site in future breeding programs.
Markergestützte Vererbungsanalyse der Pollenfertilitätsrestauration bei Winterroggen (Secale cereale L.)
(2001) Wolf, Markus; Geiger, Hartwig H.
In rye (Secale cereale L.) as in a number of other crossfertilized crops, hybrid breeding allows a targeted use of heterosis for improving yield and yield stability. The creation of hybrids in outbred rye requires an efficient system of pollination control because of the monoclinous inflorescence. In commercial seed production, mostly the Pampa (P-) Cytoplasma is used, which induces cytoplasmatic male sterility (CMS). Restoration of pollen fertility is achieved by means of pollinator lines carrying nuclear dominant restorer genes. To obtain information about the number, localization, and efficacy of the restorer genes, molecular marker based inheritance analysis in rye was performed. The results were compared to already localized restorer sources in rye and other species. Ninety-two marker loci were mapped by RFLP technique, which covered a genome-length of 845 cM. QTL (quantitative trait loci) analysis revealed a major gene on the short arm of chromosome 1R. Two RFLP markers, psr596 and bcd1124, were linked with a distance of about 0.3 cM to this major gene. Moreover, two modifying minor genes on chromosome arms 3RL and 5RL were detected. One of these minor genes showed epistatic interaction with the above mentioned major gene.