| T. zhukovskyi x T. aestivum: Among the 17 plants grown from
the second backcross, T. zhukovskyi x T. aestivum variety
"Justin3", one plant (Pl. No. 1965C-4-150) was partially male
fertile and set a few seeds on a bagged head. The remaining 16 sibs were
completely male sterile. Of the four plants that grew to maturity from the
selfed seed (produced on Pl. No. 1965 C-4-150), two plants with 20II+1I
or 19II+3I produced anthers with good pollen. Of the
other two plants, one was partially fertile and the other male sterile.
One male sterile plant (msz-Justin3-Pl. No. 1965C-4-154-1)
was crossed with pollen from Justin, and the eight msz-Justin4
plants were completely male sterile. These included two with 2 n=42 (21II)
and six with 2n=41 (20II+1I or other configurations).
The presence of hairs on leaves of the two fertile second backcross F2
plants and the purple color anthers on one of them indicated the presence
of chromosome (s) or chromosome segment (s) from T. zhukovskyi in
these plants. T. boeoticum-type x T. durum: The T. boeoticum-type diploid wheat (2n=14) was reciprocally crossed with T. durum. The F1 hybrids from crosses with the diploid as female grew slower and headed later than those from the reciprocal cross. The diploid wheat had dark brown awns and glumes, and the T. durum had normal glume and awn color (white). The F1 plants had dark black glumes and awns at maturity. All the F1 plants were highly male and female sterile. However, eight seeds were obtained from the cross, (T. boeoticum-type x T. durum) F1 x T. durum, and six of them produced mature plants. Four of these plants had 2n=29 chromosomes,one had 2n=27 and one was not studied cytologically. The latter two plants had complete male and female sterility, thin grassy leaves and straw, small narrow heads and bushy stunted growth. The chromosome pairing, fertility and vigor of these six plants are described in Tab1e 2. Only one plant (No. 3095) produced functional pollen and set seed on bagged heads. All other plants had minute anthers with nonstaining (I2KI2) empty pollen. Second Backcross: From the cross of plants 3083 and 3087 with T. durum pollen, 30 seeds were germinated and grown to maturity in the greenhouse during the summer, 1966. In general, the seedlings were weak but all survived to maturity. All plants from these crosses were completely male sterile. The anthers were extremely small in size and were dry when the florets opened. Two of these 30 plants had 2n=29 (14II+1I) chromosomes. The remaining 28 plants had normal chromosome pairing (2n=28, 14II). Obviously the transmission of the extra chromosome was low. |
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