Investigation of cold tolerance in sorghum bicolor considering survival rate under frost for genetic studies and the impact of different cytoplasm

There are currently no locally adapted varieties of sorghum, with cold sensitivity being one of the biggest problems facing sorghum production in Germany. Therefor it is necessary to increase the cold tolerance during juvenile and reproductive stage. For early sowing, it is important to find genotypes that can also survive frost temperatures for a short time. For this field and greenhouse trials have been done to investigate the survival rate of several hundreds of genotypes to identify genetic regions, which could have an impact of cold tolerance in juvenile stage. These results are used for genome wide association studies and for crossings to increase the cold tolerance in the current breeding program of the university. Another part is the comparison of different cytoplasm in isonuclear hybrids. Here the aim is to analyse the effect of the cytoplasma for juvenile and reproductive cold tolerance. These trials are done in the fields and in the climate chamber. Important traits for reproductive stage is the panicle harvest index, pollen fertility, as well as thousand kernel weight and for juvenile stage the emergence and survival under cold conditions. Both traits are not correlated to each other, so an increase in both stages is necessary to find influencing parts to cold tolerance for developing genotypes which are adapted to colder regions.