II. 16. Genetic analysis of some induced mutants.
H. Häuser and G. Fischbeck, Lahrstuhl fur Pflanzenbau und Pflanzenzuchtung, Technische Universitat Munchen, 805 Freising-Weihenstephan. "R"
1. Globe shaped grain, (glo)-mutations
Two additional glo mutants were identified
a. 1114/66, recessive mutant from X-ray treatment of cultivar Donaria, globe-shaped grain, undulated awns,
b. 1296/65, recessive mutant from X-ray treatment of cultivar Donaria, globe-shaped grain, lax ear.
Crosses with a translocation tester set indicated localization of mutant 1114/66 on chromosome 2, mutant 1296/65 on chromosome 7.
Results of test crosses with earlier glo-mutants
The segregation in cross 1114/66 x glo-cl004 indicates independent inheritance of both mutants. Therefore, a second glo-locus on chromosome 2 may be assumed. We therefore suggest to use the designation glo-dl006 for mutant line 1114/66.
In the cross mutant 1296/65 x glo-bl002 no segregation (normal or double recessives) occurred, indicating a position which is allelic or very closely linked to locus glo-b. We therefore suggest to designate line 1296/65 glo-bl007.
The criteria we use to determine globe-shaped mutants are mainly based on measuring length and width of 4 x 25 kernels and comparing the quotient L/W of parental and mutant lines. As an example, results obtained with some of our mutants in three subsequent years may be quoted:
From these results it is concluded that mutant 1339/62 and 1558/74 are carried on different loci on chromosome 6. However, a significant lack of normal and double recessive segregants in the F2 of this cross indicates linkage between both loci.
