Performance and Evolutionary Adaptation of Bulk Populations of Wheat

Abstract

The aim of this study was to investigate the potential of highly heterogeneous bulk populations ("Composite CrossPopulations", CCP) to increase sustainability and resilience of wheat cropping, a so far largely neglected approach. For this purpose, 10 CCP, generated in 2001, based on the same set of 20 older varieties, but evolved under different environmental conditions were compared with 10 recent cultivars and 10 inbred lines extracted randomly from the populations. The trials were performed over 2 years at 4 locations. Despite the older germplasm, the yields of the CCPs were similar to those of recent commercial varieties with comparable protein content, and considerably higher than that of the inbred lines. CCPs that had evolved in different environments differed in some morphological and phenological traits, indicating that adaptation to environmental conditions had taken place through natural selection. The yield stability and health of CCPs was on average higher than that of commercial varieties and considerably higher than that of inbred lines, the latter indicating that the higher stability was due to their high genetic diversity, not to their genetic background. Higher crop densities and a stronger soil cover in the juvenile stage indicate that niche complementarity among the genotypes occurs, which may contribute to an improved use of the available resources. We conclude, that the cultivation of CCP or similar heterogeneous populations represents an important opportunity to increase the resilience of wheat cultivation, which should be given greater consideration in future research and breeding.