GENETIC-ANALYSIS OF CHLORINA MUTANTS OF DURUM-WHEAT

Chlorina mutants are useful for studies of photosynthesis and as genetic markers. Three chlorophyll-deficient-durum mutants (CDd1, CDd2, and CDd6) or tetraploid wheat (Triticum turgidum L.) that have the chlorina phenotype have been identified. The objectives of this study were to determine the inheritance, chromosomal location, and allelic relationships of the CDd mutants, and to determine if the mutated locus in CDd6 was allelic to the cn-A1 locus of hexaploid wheat (T. aestivum L.). To determine the inheritance and allelic relationships of the mutant genes, the mutants were intercrossed and crossed to 'Langdon' durum. The CDd6 mutant was crossed to Chlorina-1, a chlorina mutant of hexaploid wheat. Chromosomal location of the mutant genes in CDd1 and CDd6 were determined by crossing the mutants to Group 7 aneuploids of Langdon. The F-2 segregation indicated monogenic inheritance of each CDd mutation. The mutations in CDd1 and CDd2 were allelic, and dosage effects indicated that CDd6 was homoeoallelic to CDd1 and CDd2. The mutation in CDd1 was located in chromosome arm 7BL, and the mutation in CDd6 was located in chromosome arm 7AL. The mutation in CDd6 was allelic or tightly linked to the En-Al locus of hexaploid wheat. Because the mutations in CDd1 and CDd2 were homoeoallelic to the mutation in CDd6, CDd1, and CDd2 were probably mutations of the cn-B1 locus.