| Tracing the genetic behaviour of these mutant fonns in the M3
we established that they were not constant since they segregated 3 mutant
plants and 1 plant with standard phenotype, this being an indicator for
the dominant inheritance of these mutant forms. From all the 411 plants
received, 293 were with a sphaerococcum phenotype and 118 possessed a phenotype
typical of the initial MT 47 Triticale plants. The cytological analysis has shown the availability of 42 chromosomes in the somatic cells. The described for the first time mutants sphaerococcum type in 6x Triticale are of certain interest in connection with clarifying some philogenetic and taxonomic aspects of genus Triticum L. The presence of A, B and R genomes in 6x Triticale gives suggests the following possibilities with respect to the gene determining the sphaerococcum character: a it is most likely the gene determining the sphaerococcum effect to be localized in the A or B genomes of the 6x Triticale, similar to the already described by us sphaerococcum mutants in T. monococcum L., and T. detrum (GEORGIEV 1979, 1980) . b) it is also likely that not all the chromosomes from D genome of wheat are substituted by the chromosomes of the R genome of rye in MT/47, which givs us grounds to consider that the sphaerococcum effect is determined by a gene(s) localized in chromosomes of the D genome. In this case the sphaerococcum effect of the mutant described by us is determined by a new gene with a dominant character of inheritance, which shows that it is not allelic to the recessive gene in 3D chrpmosome of T. sphaerococoum Perc., described by SEARS (1947). c) it is much less probable the sphaerococcum effect to be determined by a gene localized in chromosomes of R genome of 6x Triticale. The localization of this gene will be a subject to our future research. Literature Cited BOZZINI A. 1965. Sphaerococcoid a radiation - induced mutation in T. durum Desf., Radiation Botany, 5, 375. GEORGIEV, S. and H. NICOLOFF. 1975. EMS - induced sphaerococcum mutation in T. molcococcum L. Comptes rendus de L'Academie bulgars des Sciences, 28, 10, 1415-1417. GEORGIEV, S. 1976. EMS - induced mutants of the sphaerococcum type in T. aestivum L. Genetics and Plant Breeding, 9, 218-227. GEORGIEV, S. 1979. EMS - induced sphaerococcum mutation in T. monococcum L. Cereal Research Communications, 7, 3, 183-189. GEORGIEV, S. 1980. Cyiology of structural sphaerococcoid mutants produced in T. durum by EMS treatment. Genetics and Plant Breeding, 4, 280, 286. PRABHAKARA RAO, M.V. 1977. Mapping of the sphaerococcum gene "S" on chromsome 3D of wheat. Cereal Research Communications, 5, I. 15-17. SEARS, E.R. 1947. The sphaerococcum gene in wheat. Genetics, 32, 102-103. SWAMINATHAN, M.S., A.D. JAGATHESAN and C.V. CHOPRA. 1963. Induced sphaerococcoid mutations in T. aestivum and their polygenic and breeding significance. Curr. Science, 32, 539-540. |
| <-- Back |