| Natural hybridization of male sterile lines of common
wheat Ae. cylindrica x HOST Kosta GOTSOV and Ivan PANAYOTOV Wheat and Sunflower Institute, Tolbouhin, Bulgaria Natural hybrids of soft wheat x Aegilops, as VAVILLOV States (1966), were observed over hundred years ago. This warranted some scientists to suggest and, thereafter, experimentally prove that some species of this genera had taken part in the origination of wheat. We have been facing, in our expansive scale research work at the Wheat and Sunflower Institute, with natural hybrids of wheat x Aegilops cylindrica, quite a bit recently. This Aegilops has, to our conditions, a wide spread, particularly in the field margins and roads where no cultivation is carried out. It goes into a nearly simultaneous blossoming with wheat and favourably pollinates male sterile lines with cytoplasm of T. timopheevi. Natural hybrids of common wheat x Aegilops have not been evident in this country so far, but male sterile plants have a continuous blossoming with widely open flowers, thus enabling the pollination of other plant species and obtaining of intergeneric hybrids with a pretty good density at that. An example of this is the 1971 counting of plants from a relatively small plot, where of the 13,100 available plants of the male sterile line of Bezostaya 1,65 proved hybrids, which represents a 0.5 per cent value. These hybrid plants differ greatly to those of wheat and Aegilops. They manifest a far big hybrid vigour, the plants being up to 1.10 or 1.20 m. in height; see Fig. 1. The number of the tillers per plant goes as far as 20 or 30, or even more; the plants are completely sterile, with a pollen fertility of 2.4 per cent. Additional investigations were carried out in 1971 for a fuller elucidation of the problem of common wheat x Aegilops cylindrica hybridization as well as of the nature of the hybrids obtained. The results on Table 1 present the seed set, through manual pollination of the male sterile line of Bezostaya 1variety be almost equal (0.70 per cent) to that of the natural pollination. A comparatively bigger amount of seed set may be obtained by a reciprocal combination when Aegilops cylindrica was used as a mother plant; the seed set then amounts up to 12 per cent. Very few seeds were obtained when a backcross was made by using wheat (RB1) or Aegilops (SB1). The frequent cases of natural hybridization of sterile common wheat x Aegilops is not, of course, an obstacle for our program of producing hybrid wheat, but very probably will influence on the homogeneity and uniformity of the hybrids and should be taken into consideration for our future investigations. Literature cited VAVILLOV, N. I. 1966. Izbranije sochinenija "Genetika and Selaktsija", published by "Kolos", Moskow. (Received January 11, 1972) |