Potential Selection System for Mutants with Increased Lysine, Threonine, and Methionine in Cereal Crops¹

Abstract

Simultaneous addition of lysine and threonine inhibits growth in maize ( Zea mays L.) callus cultures and embryo cultures from several cereals. Methionine or homoserine reverses lysine‐threonine inhibition. Isolation of feedback inhibition resistance mutants is proposed for several cereals by selecting callus or seedlings which grow in the presence of lysine‐threonine. Resulting mutants may be overproducers of lysine, threonine, or methionine.