Tassels from field donor plants before anther culture were preliminarily treated with low temperature (8 C) for 14 days. Anthers were explanted on solid nutrient medium UP according to Genovesi, Collins (Crop Sci., 1982, 22: 1137-1144). Up to 1993, the explantation of anthers was made beginning from the 1-cellular vacuolated stage, and after 1993 explantation was made beginning from the stage of the young 2-cellular pollen grain. The analysis concerned the percentage of responsible anthers (anther response, %) and the number of embryo-like structures per 100 anthers (ELS/100 anthers). The results of comparison of androgenic ability of reciprocal crosses are presented in Tables 1 and 2.
Table 1. Anther response (%) of maize reciprocal hybrids.
Table 2. Number of embryo-like structures per 100 cultivated anthers of maize reciprocal hybrids.
Significant differences were observed for H99xWf9 and its reverse combination in 1992, 1993 and 1995 for both indices of androgenic activity. In the other years, reciprocal differences could not be certified. For anther response, differences between B14xWf9 and Wf9xB14 were demonstrated in three of the six years of the investigation, for ELS/100 anthers in two of the six years. Reciprocal effects were not established for anther response between B14xAnd44, And44xWf9, H99xAnd44 and their reverse combinations which had been analyzed during 1-2 years. For ELS/100 anthers, differences between reciprocal crosses were observed only for B14xAnd44 in 1997 and Wf9xAnd44 in 2000.
It is necessary to emphasize that for the same reciprocal crosses in various years, some positive effects were shown by different maternal forms. In crosses H99xWf9 and Wf9xH99, B14xWf9 and Wf9xB14 all the lines being used as female plants caused the exceeding of values in different years. The results have demonstrated not very much exceeding of values due to the exchange of position of lines in the hybrid either. It was 0.34-4.07% for anther response and 0.34-9.87% for ELS/100 anthers.
Thus, reciprocal effect on the development of androgenic induction in
maize anther culture was unstable, which led to its manifestation only
in some years of the investigation in individual cross combinations. The
results represented here show that the main role in the determination of
androgenic ability in maize belongs to nuclear genes.
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