DISOMIC AND DITELOSOMIC ADDITIONS OF DIPLOID AGROPYRON ELONGATUM CHROMOSOMES TO TRITICUM AESTIVUM

Abstract

A set of disomic addition lines was produced in which each chromosome of Agropyron elongatum (2n = 14) was added to the chromosome complement of Triticum aestivum cv. Chinese Spring. In addition a complete set of ditelosomic addition lines involving Agropyron chromosome arms IS, IIα, IIIα, IVS, IVL, VS, VL, VIS and VIIα, was developed. Except for disomic addition line VII which is similar to Chinese Spring, each added alien chromosome pair was found to have a specific effect on plant morphology. Five disomic addition lines had reduced fertility. Agropyron chromosome arms carrying genes for anthocyanin production, waxless foliage, tenacious glumes, and several other traits were identified. The single Agropyron chromosomes in the monosomic addition lines usually have either minor effects or no effect on plant morphology and fertility.The disomic addition lines are similar in many characters to tetrasomics of the corresponding homoeologous wheat chromosomes and show characters that are not present in either Ag. elongatum or the amphiploid, T. aestivum × Ag. elongatum. Thus many of the effects are due to gene dosage. If individual disomic addition lines are compared with the amphiploid a significant role of interchromosomal gene interactions is apparent.In combination with knowledge of the homoeologous relationships among wheat and alien chromosomes, sets of disomic addition lines can provide valuable information on the evolutionary past of genomes in Triticinae. In monosomic addition lines only Agropyron chromosome IV paired with a wheat chromosome and it is concluded that it is improbable that Agropyron genomes played any role in the evolution of the polyploid series of Aegilops and Triticum.