THE CYTOGENETICS OF A DITELOTETRASOMIC LINE IN BARLEY

Abstract

A ditelotetrasomic line (14+2−1S) carrying two telocentric chromosomes in addition to the normal complement was isolated in the selfed progeny of a monotelotrisomic (14+1S) of barley. The plants were shorter and later maturing than the disomic, and highly sterile. In diakinesis and metaphase I cells at meiosis, the extra telos showed a high frequency of pairing with each other and with their normal homologues, resulting in 6″ + (t″ + 1″) and 7″ + t″ as the most frequent configurations. Regular meiotic behavior at subsequent stages resulted in a 42.2% frequency of pollen transmission of the extra telos. Selfed progenies gave rise to 7.1% diploids, 45.7% monotelotrisomics and 47.2% ditelotetrasomics.