Influence of an Extra Pair of Fragment Chromosomes on Grain Yield in a Hexaploid Oat

Abstract

Three hundred panicles were selected from a population of CI 9192, a hexaploid oat (Arena sativa L.) with 42+2 fragment chromosomes. When panicle progenies were treated as lines and tested for uniformity of crown rust reaction, 258 lines were found resistant to race 264B of the crown rust fungus (Puccinia coronata Cda. avenae Fraser and Led.), and the remaining 42 were susceptible. The susceptible lines had lost both chromosome fragments and were normal hexaploids. All lines were grown in rust‐free conditions in a hill‐plot test. No differences betweent he rust‐resistant and rust‐susceptible groups were detected for plant height and heading date, but the susceptible group was significantly higher yielding than the resistant group.