| Transmission of monosomes and trisomes in an Emmer
wheat, T. dicoccum var. Khapli K. TSUNEWAKI National Institute of Genetics, Misima, Japan As reported earlier (KIHARA and TSUNEWAKI 1960, 1962; TSUNEWAKI 1962), several aneuploids of an Emmer wheat, T. dicoccum var. Khapli were produced among polyploids by N2O-treatment of artificially pollinated spikes. Three monosomics and 6 trisomics were obtained so far. Transmission of the monosomes and trisomes to their offspring has been studied. The result is summarized in Table 1. No monosomics were recovered in the offspring of all 3 monosomics, although 2 trisomics were found. No transmission or a very low one of monosomes seems to be due to the low fertility of chromosome-deficient female gametes, becaus seed fertility of the monosomics was very low (about 30%) even at artificial pollination with pollen giains from disomic Khapli. This fact indicates that monosomics of, at least, this Emmer wheat are not suitable for genetic investigation, except that they might serve as a source of trisomics. On the other hand, many trisomics (24% on the average) were obtained in the offspring of trisomics. A single tetrasomic was also found. Transmission rates of the trisome through female and male gametes were estimated to be 23% and 2%, respectively. Transmission rate of the trisome in this Emmer wheat is much lower than that reported for common wheat but is almost the same as in barley. Trisomics of the employed Emmer wheat, therefore, may be convenient for genetic study. |