Pollinating the silk of an ear with five marked pollen components with a possibility to differentiate the seeds
--Toma Dankov, Miglena Kruleva, Zlatka Bojilova

Determining the genotype of a given maize plant, used as a pollinator on defined female testers, is reached quickly and easy by dividing the pollen. This, however, is realized slowly if the plant is male sterile and can be used only as a mother component. Some possibilities in that direction are given by the availability of more than one ear on a plant (Dankov, MNL, 47:6-7, 1973). Up to now the pollination of the one ear from two different pollinators by dividing the silk was used. Greater possibilities in that direction are proposed by the great number of markers on the embryo, endosperm and seedlings.

Since 1988 we have been working on the creation and utilization of such markers in connection with haploidy. In 1993 and 1994 we realized the pollination of 3-4 ears from A632 cms-C and B37 cms-C lines with 5 pollinators for each ear - self pollen (without marker), colored embryo, embryo-endosperm marker and protruding embryo. The silk was divided into 5 parts by lightly binding with thread (Fig. 1), after which a cardboard separator was used to pollinate each part separately (Fig. 2). For one ear we obtained 30-50 seeds, which we distinguished by a dominantly inherited marker of the pollinator. Only about 3% of the seeds remained undefined, possibly connected with an embryo-endosperm marker or the heterofertilization.

The transfer of markers continues on the following C-type sterility testers:

N rf4 rf4 Rf5 Rf5 Rf6 Rf6 (endosperm marker)
N Rf4 Rf4 rf5 rf5 Rf6 Rf6 (coloured embryo)
N Rf4 Rf4 Rf5 Rf5 rf6 rf6 (protruded embryo)

Figure 1.

Figure 2.


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