Chestnut Hill, Massachusetts
Transposable element in maize anther
culture-derived microspore-plants and their progenies
--Ting, YC, Tran, L
In the last few years, selection of stable
inbred maize from anther culture-derived progeny plants was made (MNL74:73).
This inbred line was descended from a single self-fertilized PO (first
generation of microspore-plant) plant of KH-13. Every summer, more than
100 progeny plants were grown in the field for observation. Among them,
five to 10 percent were classified as dwarf-yellow-green. These potential
mutants were weak, had barren stalks and had sterile male inflorescences.
It was almost impossible to make any further genetic evaluation on them.
However, in each summer, three to five of the normal sib plants were selected
and self-pollinated. In the next year, those self-fertilized kernels were
employed for further testing. More than 100 plants were grown again for
study. The dwarf-yellow-green plants reappeared in the new progeny . When
a X2-test was made, the frequency of the appearance of these mutant plants
did not fit the expected ratio of either monohybrids or dihybrids. The
above experiments were repeated for more than five years. Last summer,
the same procedures were followed. It was surprising to find that no dwarf-yellow-green
variants were observed. In other words, the selected progeny plants had
become a stable line. Its immediate offspring were close to 100 percent
fertile and uniform in morphology. It is concluded that the previous segregations
of dwarf-yellow-green vs. normal plants were an indication of the presence
of a transposable element in the parental plant. This element was originally
silent and activated through anther culture. It is conceivable that after
being through more than five generations of self-fertilization, the transposable
element was thrown out by irregular meiotic division. Furthermore, it is
tenable to say that anther culture of maize may lead to the production
of useful inbreds. These inbreds can be employed to facilitate the improvement
of food supplies.
Please Note: Notes submitted to the Maize Genetics Cooperation Newsletter may be cited only with consent of the authors.
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