Natural Genetic Diversity and Crop Improvement

With the human population expected to exceed 9 billion by 2050, food production will need to increase significantly in the coming years. In particular the forecast doubling in cereal demands requires improvement of yields of the top four cereal crops, maize, rice, wheat and barley. This goal is made more challenging by global environmental changes and the connected abiotic and biotic stresses. In this chapter we briefly discuss two different breeding strategies to increase cereal yield: the heterosis approach in maize and the ideotype approach based on knowledge of the genes controlling yield components in rice. We further discuss the importance of crop genetic diversity in connection to studies of the domestication history of maize, rice, wheat and barley. We present examples of how crop genetic resources including landraces and wild relatives have been used in genetic improvement of yield and adaptation to biotic and abiotic stresses. More extensive deployment of such resources to face future challenges is now empowered by new genomic tools enabling efficient exploration of genetic variability and innovative approaches to direct collection and conservation of genetic resources for food and agriculture.

Keywords: Adaptation, Barley, Breeding, Conservation, Crop genetic resources, Genetic diversity, Grain yield, Maize, Rice, Wheat.