| Chromosome pairing and fertility in the hybrid between
the new amphidiploid-SlSlAA and Emmer-wheat
Masatake TANAKA Laboratory of Genetics, Faculty of Agriculture, Kyoto University, Kyoto, Japan The present writer has obtained an amphidiploid from the cross, Aegilops longissima (genome formula. SlSl x Triticum aegilopoides (genome formula, AA). Data on chromosome pairing and fertility in the amphidiploid (genome formula, SlSlAA) are summarized in Table 1. Crosses between the amphidiploid (SlSlAA) and T. durum (AABB) were made to test the chromosome homology (Table 2). In the hybrid, SlSlAA x T. durum, 5-9 (mode at 7) bivalents were observed (Fig. 2 on the cover), and the F1 hybrid was entirely sterile. The 7 pairs of chromosomes observed might be attributed to allosyndesis between the A genomes of the parents. This indicates that the A-genomes of the parents are homologous. However, from the genome-analytic point of view, the Sl-genome cannot be homologous to B-genome. From the morphological point of view, the S group, incl. Ae. speltoides (S), Ae. Aucheri (S), Ae. bicornis (Sb), Ae. longissima (Sl) and Ae. sharonensis (Sl), especially Ae. longissima and Ae. sharonensis, has some characteristics of the B-genome of Emmer-and Dinkel-wheats. For example, Ae. longissima has a hollow straw with a thick wall, which is one of the main characteristics of the B-genome. The amphidiploid resembles the Emmer wheat in some characteristics, i.e., the empty glume is narrow and has an apical tooth in place of awn, but the keel is sharp, the palea does not split, and the ears break according to the wedge type. But it differs from the Emmer wheats in other characteristics. The ears are long and narrow, and as the awns of the lemmas are of equal length, the tips of the awns are not at the same level, and the straw is slightly hollow. |