Studies on the production of amphidiploids as the sources of resiStance to leaf-ruSt in wheats : I. Cytogenetical studies on the F₁ hybrids and the amphidiploids, Triticum Timopheevi ZHUK. X Aegitops squarrosa L.

Abstract

The present writers attempted to synthesize 6x amphidiploids with the similar genome constitutions. AAGGDD, to the common wheats. AABBDD, by the artificial hybridization between Triticune Timopheevi ZHTJK. (AAGG, 2 n = 28) and Aegilops squarrosa L. (DD, 2n=14) as one of the means to obtain the sources of resistance to leaf-rust in wheats. By applying 0.05% colchicine solution to the F₁ seeds obtained, 152 amphidiploids in addition to one haploid plant were obtained successfully, although the appearance df the haploid plant was contrary to our expectations. The chro.mosome association and the fertility of F₁s and amphidip.loids were shown in Table 13 in comparison with the results of MCFADDEN et SEARS (1947). Laggards and bridges were frequently observed both at Ist and 2nd anaphase or telophase in Fls and amphidiploids.As a result of such irregularities in meiosis, in Fls there appeared triads, tetrads with micronuclei, and polyads such as pentads, hexads and heptads, above all pentads and hexads being observed domparatively frequently.