Quantitative-trait loci (QTL) mapping of important agronomical traits of the grain and biomass production in winter rye (Secale cereale L.)

摘要

Rye is an important crop in Northern and Eastern Europe and mainly used for food and feed and became most recently important for biogas production. Hybrid rye varieties dominate the cultivated area, which is mainly on light and sandy soils, because rye has a relatively high tolerance to biotic and abiotic stress factors. Climate change will also affect Central Europe, causing higher temperatures and less precipitation in spring and summer. Rye will be influenced more by these effects than other cereals because it is mainly grown on marginal environments.Rye has a high potential for being used as a biogas substrate, but detailed information on improving this trait in hybrid rye is missing. Until now, no study that analyzed phenotypic and genotypic agronomic traits for using rye for biogas production exists. Further, there is only one study, which dealt with the influence of periodic drought stress in rye cultivated areas. Beside this, we analyzed yield stability over a wide range of environments in consideration of drought stress in Central Europe. We analyzed an interpool hybrid population (Pop-D) in 2011 and 2012 at seven environments in Germany for the biomass yield and grain yield (Publication I). This study showed low correlations between grain yield and dry matter yield (r = 0.33). Higher correlations were obtained with two plant height measurements (at heading time, r = 0.64; before harvest, r = 0.52) and dry matter yield. The indirect selection via plant height was superior in contrast to the direct selection of dry matter yield by factor 1.24. Genotypic results confirmed phenotypic results as no overlapping QTL for grain yield and dry matter yield were detected (Publication II). However, we identified common gene regions for plant height and dry matter yield due to the high correlation between both. Plant height is a promising trait for indirectly selecting high biomass yielding varieties. The paradigm shift from shorter plants with high grain yield to taller hybrids as a resource for biogas substrate needs additional breeding efforts for lodging resistance.In Publication III we analyzed two intrapool populations (Pop-A and -B) and one interpool population (Pop-C) at 16 – 18 environments (location x year combinations) under irrigated and rainfed conditions in Germany and Poland. Yield stability was high over a wide range of environments, even when drought stress environments were included. This illustrates the adaption of rye to marginal and drought stress environments. The analyzed populations showed no differences within yield stability, but yield differences between inter- (Pop-C) and intra-pool (Pop-A and -B) crosses were visible. Selection for yield stability is possible due to the genetic variance for this trait within all three populations. Therefore, it is important to select genotypes with low genotype x environment interaction. All three populations showed high yield stability on a high yield level and were already well adapted to extreme weather events caused by climate change. It is recommended to use highly diverse environments with irrigated and rainfed conditions to select on yield stability and high yielding varieties under optimum and drought conditions