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Chromosome pairing and fertility in some interspecific
hybrids of synthesized hexaploid wheats Jun-ichiro TABUSHI Kyoto Kasei College, Uji, Kyoto, Japan In the past, interspecific hybrids among synthesized hexaploid wheats have not yet been studied, except ABD-2 x ABD-3(TABUSHI 1965) and ABD-1 x ABD-4 (TABUSHI 1968). In this paper the results of chromosome pairing and fertility of F1 hybrids between ABD-1 or ABD-4 and various other synthesized hexaploid wheats or a common wheat species are described. Chromosome pairing in F1 hybrid between ABD-1 and ABD-4, ABD-5, ABD-11 or T. vulgare erythrospermum (T.v.e.) was poor as compared with that in ABD-1. Namely, the range of chromosome pairing was wide, and many univalents was found often in each PMC as shown in Table 1, e.g. 20II+2I-6II+30I. On the other hand, chromosome pairing in F1 between ABD-4 and ABD-9, ABD-10, ABD-12 or ABD-13 was somewhat poor, but F1 between ABD-4 and ABD-11, ABD-16a, ABD-16b, ABD-21 or ABD-23 showed good chromosome pairing roughly similar as ABD-4 (Table 2). ABD-1, ABD-9, ABD- 10 and ABD-12 are the progeny of the same cross combination of T. dicoccoides spontaneonigrum x Ae. squarrosa, though varieties or strains of Ae. squarrosa used in the crosses were different. As given in Tables 1 and 2, F1 hybrids between above mentioned synthesized hexaploid wheats (ABD-1, ABD-9, ABD-10 and ABD-12) and other synthesized hexaploid wheats showed almost always poor or somewhat poor chromosome pairing. In all the F1 hybrids involving ABD-1 except ABD-1(female) x ABD-11 (male), namely ABD-1(female) x ABD-4(male) and its reciprocal, ABD-1(female) x ABD-5(male) and ABD-1(female) x T.v.e.(male), showed poor pollen fertility (Tables 3 and 4) and seed fertility (Tables 5 and 6). F1 hybrids ABD-4(female) x ABD-11(male), ABD-4(female) x ABD-16b(male), ABD-4(female) x ABD- 21(male) and ABD-4(female) x ABD-23(male) showed good fertility, but ABD-4(female) x ABD-9(male) and its reciprocal, ABD-4(female) x ABD-10(male), ABD-4(female) x ABD-12(male), ABD-4(female) x ABD-13(male) and ABD-4(female) x ABD-16a (male) showed poor or somewhat poor fertility. (Received September 30, 1969) |