The objective of this study was to characterize Dr. Loesh’s o2 converted lines relative to their recurrent parents and to verify that they have the o2 genotype. To accomplish this, I planted one row of each line adjacent to one row of the corresponding recurrent parent at the Iowa State University Agronomy Farm in the summer of 2001. The resulting plants were characterized phenotypically on the basis of their plant height, ear height and pollination date (see Table). With the exceptions noted in the table, the inbreds were phenotypically similar to their recurrent parents.
In order to verify that the Loesh inbreds carried the o2 mutation, each of these lines was crossed to an o2 mutant tester from the Maize Co-op Stock Center (701D). In all cases, the o2 genotype was confirmed.
These lines will be valuable for comparing the effect of different genetic backgrounds on the o2 mutation, and may also be useful to breeding programs aimed at improving nutritional quality with the o2 mutation. Seed of these lines has been sent to the Maize Co-op Stock Center for maintenance and distribution.
Table. Phenotypic characterization of inbred lines and their o2
|Pedigree||plt hta||ear ht||pol dateb||comments|
|B14A||**||NS||-2||o2 small kernels|
|B46||*||NS||2||O2 red cob, o2 white cob|
aPlant and ear height measurements are the average of the first five plants in the row. NS indicates the difference between the inbred line and its o2 conversion is not significant, ** significant to P=0.05, * significant to P=0.1
bPollen date = (number of days after planting when half the
plants in the O2 row first shed pollen) — (number of days after
planting when half the plants in the o2 row first shed pollen)
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