There is reason to predict that some kinds of crossover deficient meiotic mutants might lead to regular production of unreduced eggs. Mutations which block crossing over, in the presence of normal homologue pairing and synaptonemal complex formation, might have such an effect (see Chromosoma 65:173-183, 1978 and Exp. Cell Res. 112:297-308, 1978). Homozygotes for such mutations, in the presence of the additional features of capacity for diploid embryo and diploid endosperm development, would be expected to produce viable seeds without fertilization. The probability of natural occurrence of the fortuitous combination of events required is of course vanishingly small, but self-pollinated mutagen treated material is a somewhat more promising potential source. This leads to the suggestion that investigators who grow large mutagen treated progenies, and bag numerous earshoots, which are left bagged but unpollinated, may have a rare opportunity to find a parthenogenetic stock source, simply by checking for development of ears from unpollinated (covered) earshoots. This can probably be done effectively by feeling, without picking or husking. It is the purpose of this note, not only to suggest that such a search be made for a parthenogenetic stock source, but also that I would be very interested in studying its meiosis.

Marjorie Maguire

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