By backcrossing to the F
1s of (
Triticum Timopheevi×
T. vulgare) with their parents, 24 BF
1 plants were obtained, of which 21 plants were raised by the pollen of
T. vulgare. And our cytological observations were carried out principally on them.
Consequently it ws found that these 21 BF
1 plants were consisted of the plants having 2
n=37 (1 plant), 2
n=38 (4 plants), 2
n=39 (7 plants), 2
n=40 (4 plants), 2
n=41 (4 plants) and 2
n=42 (1 plant) respectively, the mode of 2
n chromosome number being in 39. From this, it can be infered that of the gametes formed in F
1 plants, these having 18 chromosomes play best their function as female.
Moreover, the behaviour of chromosomes at MI of P.M.Cs. was observed somewhat in detail on the 7 plants with different chromosome numbers, of which 1 plant having 2
n=30 chromosomes was the one backcrossed by
Timopheevi (see Table 2 and 3).
As a result of these observations, it became evident that by backcrossing the numbers of univalents and multivalents in BF
1 plants decreased considerably, but the numbers of bivalents, especially of closed bivalents increased in comparison with those in F
1s, and therefore the fertility of BF
1 plants was raised strikingly.
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