| Hybrids between synthesized 6x wheat, ABD No.
4, and a Japanese commercial wheat variety, Norin No. 25 Jun-ichiro TABUSHI Kihara Institute for Biological Research, Kyoto, Japan Chromosome pairing and fertility: One of the synthesized hexaploid wheats, ABD No. 4 (Triticum persicum var. stramineum x Aegilops squarrosa No. 2), was crossed with a Japanese commercial wheat variety, Norin No. 25. The F1 plants were vigorous and showed fairly good chromosome pairing at MI (Table 1). Pollen-fertility of one of the F1 plants was 80.0%, and its seed-fertility by selfing was 84.2%. 39 F2 individuals derived from this F1 plant also showed fairly good chromosome pairing, but the pollen-fertility fluctuated from 48.9 to 100%, and the seed-fertility by selfing from 5.0 to 100.0%, with an average of 90.0%. F3 plants showed comparatively high fertility. Characters of F1, F2 and F3 plants: Some of the F1, F2 and F3 plants were examined for a few characters in comparison with their parents as given in Table 2. F1 was intermediate in the flowering time, but in size and weight of the seeds and in flintiness it was superior to the parents. 5 out of 39 F2 individuals were still better with respect to the flowering time, size and weight of the seeds and the flintiness. 3 out of 30 F3 offspring derived from F2-4 were as good as the mother plant in certain respects (Table 2). |