Compensating ability in pollen fertilization between group-6 and-7 homoeologous chromosomes of barley and wheat

By using alpha -amylase isozymes as markers for chromosomes of homoeologous groups 6 and 7, we analyzed the segregation of chromosome constitution in the progenies from crosses between double-ditelosomic or ditelosomic lines of hexaploid wheat cultivar 'Chinese Spring' (CS) as the female parent and double-monosomic F-1 hybrids of CS x wheat-barley substitution lines for ba rley chromosomes 6H or 7H. From this analysis we estimated the transmission rate via pollen of barley chromosomes 6H and 7H in the double-monosomics a nd evaluated the compensating ability between barley and wheat chromosomes in homoeologous groups 6 and 7. The results indicated that both 6H and 7H s howed their highest compensating ability for their respective homoeologous wheat chromosomes 6A (37.5% transmission rate) and 7A (39.4%), intermediate for 6D (34.1%) and 7D (29.6%), and lowest for 6B (26.6%) and 7B (22.6%) ch romosomes.