[A fundamental change in construction of the barley flower in the mutanttricomposiflora].
FollowingX-ray treatment of caryopses of the winter barley 'Dominator' a mutant was selected which is characterized by an extreme morphological alteration in flower structure. The plants do not form any reproductive organs but replace them by secondary flower triplets between glume and lemma. This type of ramification can continue to make spikeltes of the fifth order. Consequently the mutant was given the name "tricomposiflora" and the genetical symbol "tric" proposed. The type of ramification resembles a manifold composed umbel. The mutant is absolutely sterile and can only be propagated by heterozygous individuals. Further morphological alterations of the mutant compared with the original form are described.The genetic behaviour of the mutant was checked on heterozygous progenies. In theF 2-generation the mutant types occurred according to the 9:7 (normal: mutants) segregation ratio. The genetical analysis of the following generations (F 3,F 4) fitted very well the assumption of a dihydbrid segregation pattern with two homomeric genestric 1 andtric 2.The discussion is mainly concerned with different types of ramification in barley induced by mutation, the importance of such alterations in forming new characters and their evolutionary significance.
Institut für Pflanzenzüchtung der Martin-Luther-Universität Halle-Wittenberg in Hohenthurm bei Halle, Saale.
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Krausse