Unstable progeny of a dihaploid maize line

In the last summer, about 70 kernels of a self-fertilized plant which originated from a maize mutable plant height strain were sown. This maize strain, a dihaploid with 2n = 2x = 20, descended from a microspore-plant by natural chromosome doubling. Two weeks after sowing, 47 healthy seedlings were obtained, indicating a more than 60 percent seed viability. All of them looked alike. In other words, uniformity was persistent in the early stage of growth. However, about six weeks after planting, some plants began to show slow growth, leaf-chlorophyll deficiency and gradual weakening. Within a short period these plants would die.

When the living plants reached tasselling stage, only 21 individuals survived. Among them, variability in number of ears and plant height was striking. For plant height, it ranged from 27.5 to 183 cm, and for number of ears per plant, it ranged from 1 to 3. In addition, two of the 21 plants bore tassel seed. Self-pollinations for a selected number of plants were made. Further studies will be carried out on the progeny instability of the plants.

Y.C. Ting

Please Note: Notes submitted to the Maize Genetics Cooperation Newsletter may be cited only with consent of the authors.

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