Many investigators who have worked with Mo17 have been impressed by the extent to which it suppresses the expression of a wide variety of mutations. Factors whose expression is reduced in this background include seed and plant color factors (A, C, R, B, Pl), chlorophyll mutations (g, g2, cl), dominant morphological mutations (Cg, Tp1 Tp2) and disease lesion mutations (Hoisington, pers. commun.). If this trait is indeed general, then it is not only of fundamental interest but is also of considerable practical importance. It is often desirable, for example, to suppress the expression of a mutation in order to maintain or manipulate stocks. This is true in the case of Cg, Tp1 and Tp2, which do not produce pollen in many genetic backgrounds. The fact that the suppressive ability of Mo17 is associated with an extremely high combining ability suggests that this trait may also be useful for breeding purposes. The idea of using suppressive ability as a way of selecting elite inbreds is not new. Zuber tried to use a set of knotted mutations for this purpose some time ago, apparently without much success. Nevertheless, it might be worthwhile to try this approach again using a combination of different types of mutations.

Scott Poethig
 
 

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