INTERACTION EFFECTS IN HEXAPLOID WHEAT INVOLVING AEGILOPS COMOSA CHROMOSOMES AND CYTOPLASM

Abstract

Interaction studies of nucleus and cytoplasm in aIIoplasmic hybrids involving one or two chromosomes of cytoplasm donor, Aegilops comosa (2n = 14), and genomes of seven varieties of common wheat, Triticum aestivum (2n =42), were made. The plants normally exhibited delayed heading, reduced vigour, complete male.sterility and partial or complete male fertility. On the contrary, however, some of the 43- and 44-chromosome plants showed considerable restoration of male fertility with normal or increased vigour and set normal seeds after selfing. Meiotic analysis showed two critical comosa chromosomes involved in interaction for fertility restoration which were identified to be median or submedian and satellite (nucleolus organizing) chromosomes. In addition, some undesirable side effects on the morphology of some plants were also observed which need rectification.