| Aneuploidy and fertility in amphidiploid wheat-rye
hybrids K. D. KROLOW Institut fuer Vererbungs- und Zuechtungsforschung der Technischen Universitaet Berlin Fakultaet fuer Landbau Berlin - Dahlem, Germany [I] Investigations on aneuploidy and fertility of octoploid wheat-rye amphidiploids gave the following results : l. Populaion plants out of 35 different lines of amphidiploid wheat-rye showed a frequency of aneuploidy on an average of 83.3%. 2. A selection of highfertile single plants decreased the percentage of aneuploids in the offspring to an average value of 60.6%. 3. The most effective method of selection was to select hignfertile single plants from progenies with highest fertility. The percentage of aneuploids in the offspring of these plants could be diminished to an average value of 40.3%, 4. It was not possible to select an amphidiploid wheat-rye line which was completely constant in the chromosome number. The best line showed even now 36.4% aneuploids in the offspring. 5. In relation to the fluctuation of the chromosome number in the offspring triticale lines with relative low variation in the chromosome number were found to be very little influenced by the genetic constitution of the amphidiploids. The progenies of single plants with highly different genetical origin showed nearly the same proportion of aneuploids. 6. In the offspring of the most plants the distribution of somatic chromosome numbers showed a tendency to revert to lower chromosome numbers. In populations the proportions of plants reverted to chromosome numbers of wheat was found on the average of 2.6%. 7. Between somatic chromosome number and fertility an intimate correlation could be observed. Hypo- and hyper-aneuploids with 55 respectively 57 chromosomes showed already a reduction in fertility of on an average 11 resp. 15%. 8. Between euploid and aneuploid plants the differences in plant height were lower than the differences in fertility. Aneuploid plants with 55 chromosomes showed a reduction in plant height on an average of 4%. Aneuploids with 57 coromosomes showed a reduction of 7%. 9. With increasing aneuploidy a further reduction m fertility and plant height seems to take place. |
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