| Among the synthesized wheats (rf. Table 2),
the seed fertilities of ABD-13 and ABD-22 could not be estimated as all
the F1 plants remained dwarf throughout the growing season and
did not head. ABD-1, ABD-16 and ABD-Golden Ball restored fertility up to
53.6%, 76.8% and 9.2% respectively, in the F1s. Though ABD-1
and ABD-9 have the same emmer parent, only the former restored fertility.
Therefore, the restoring gene (s) of ABD-1 is assumed to have been derived
from its squarrosa parent (Ae. squarrosa var. typica
strain No. 1). Similarly, ABD-14 and ABD-16 have the same emmer parent,
and only the later had restoring gene(s). In this line, too, the gene(s)
seems to have been derived from Ae. squarrosa parent. Fertility-restores for T. timopheevi cytoplasm: Out of 73 T. aestivum varieties or strains tested for T. timopheevi cytoplasm, only three, namely, BMUK Nos. 3769 and 3770 of Egyptian origin and BMUK No. 3801 from Turkey were found to possess very weak restoring gene(s), because their F1 hybrids restored some fertility (0.7, 3.4 and 12.6% respectively), all the rest gave completely male-sterile F1 hybrids (Table 1). In the other 6x species, only T. spelta var. duhamelianum was found to carry restoring gene and exhibited very high seed fertility (98.5%) in the F1. Among the 12 synthesized wheat strains tested (rf. Table 2), only ABD-Carleton was found to carry some weak restoring gene(s). KIHARA and TSUNEWAKI (1967) reported that T. dicoccoides var. spontaneonigrum, T. carthlicum and many others carry some restoring genes to T. timopheevi cytoplasm. On the other hand ABD-1 and other synthesized wheats did not behave as a restorer. MAAN and LUCKEN (1968) showed that T. aestivum Chinese Spring with T. timopheevi cytoplasm became completely male sterile, while its mono-7D restores some fertility. All these facts indicate that D genome in common wheat as well as in Ae. squarrosa carries some inhibitor to fertility restoration. It is interesting to note that none of the 92 varieties or strains of 6x wheats tested for Ae. ovata and T. timopheevi cytoplasms was found to carry restoring genes in common for these cytoplasms. The restorers, which induced partial or complete fertility in Ae. ovata cytoplasm, did not function in T. timopheevi cytoplasms and, similarly, the strains, which induced complete or partial fertility in T. timopheevi cytoplasm, did not show any sign of fertility-restoration in Ae. ovata cytoplasm. The interaction between restorer and malesterile cytoplasm is undoubtedly very specific. (Received September 8, 1969) |
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