Mutations Affecting the Root System
Many thousands of mutants of a large number of different crops are known that show alterations in the shoot system in the broadest sense of this term, hundreds of them being of direct interest for realizing specific aims of breeding. It can be assumed that a relatively large proportion of genes of a genome controls the development and functionability of the root system of a plant. Mutations of these genes should realize distinct alterations of this plant organ. Pleiotropic effects influencing both shoot and root in a corresponding way may exist in exceptional cases. In general, however, it can be expected, that the characters of the shoot and the root system of our crops are controlled by different genes which mutate independently from each other. The small number of findings available in this field confirm this assumption. It is conceivable that the effectiveness of the root system with regard to water and nutrient uptake could be improved under the influence of some mutant genes. In this way it could be possible to improve the physiological capacity of a crop to some extent.