A SELF-FERTILE TRIGENERIC HYBRID, TRITICUM-AESTIVUM X AGROPYRON-MICHNOI X SECALE-CEREALE

Trigeneric hybrids between the (Triticum aestivum x Agropyron michnoi) F1 (CM, 2n = 5x = 35; ABDPP) and two winter rye (Secale cereale L., 2 n = 2x = 14; RR) cultivars, 'Wugong 774' and 'AR-132', were synthesize d. Such trigeneric hybrids could be used to transfer resistance genes for powdery mildew from rye to CM and subsequently to common wheat and to identify (1) the effects of the P genome of Agropyron on the self- fertility of the hybrids and (2) the differences in genetic background between rye cultivars with marked differences in pollinating habit. T he trigeneric hybrids varied widely in morphology and showed a high le vel of resistance to such diseases as barley yellow dwarf virus (BYDV) , stripe rust, leaf rust, stem rust, and powdery mildew. Selfed and ma ny backcross derivatives were obtained from the trigeneric hybrids. Th e results indicated that rye cvs 'Wugong 774' and 'AR132' arose from d ifferent gene pools and that the P genome of Agropyron carries gene(s) responsible for chromosome segregation, leading to functional gamete formation and self-fertility of the hybrids. The F2 and BC1 plants cou ld be obtained in two ways fusion of the unreduced gametes and the ass umed apomixis of unreduced female gametes in the trigeneric hybrid pla nt II-4 which indicates that this trigeneric hybrid may be a special g enetic stock. Chromosome pairing in the trigeneric hybrids and ways of producing wheat/rye and wheat/Agropyron translocations are discussed.