The aim of our investigation was to study the male gametophyte reaction at the pollen germination and pollen tube growth stages in high temperature stress condititons. The 346 and 502 inbred lines, and their waxy counterparts, as well as their MR3 progeny (obtained from irradiated immature embryos in vitro), were taken as the experimental material. Fresh collected pollen from each genotype was subjected to high (+35 C) temperature treatment for 20 minutes. After that pollen was cultivated on the nutrient medium (developed by Cook F.S., Walden D.B., Can J. Bot. 43:779-786, 1965) for 3 hours at 24 C to determine pollen viability.
As a result, a significant variability of male gametophyte viability among plants of MR3 generation was found. In general, the high temperature treatment resulted in decreasing of maize pollen viability. However, in some cases we have also observed increasing of viability. The reliable effect of genotype and temperature was revealed by two factor analysis of variance (Table 1). The results obtained indicated that pollen viability of MR3 progeny of inbred lines 346 and 502 was more genotype-dependent than that of their waxy counterparts. As the results also show, pollen viability of MR3 progeny of inbred line 502wx1 depends mostly on the temperature factor. The same character of the other waxy counterpart proved to be the most genotype and temperature interaction dependent.
Table 1. Genotype and temperature effect (%) on male gametophyte viability.
| MR3 progeny of inbred lines: | Factors | ||
| genotype | temperature | their interaction | |
| 346 | 73.44*** | 7.47*** | 16.61*** |
| 346wx1 | 47.76*** | 2.91*** | 56.19*** |
| 502 | 81.72*** | 4.34*** | 9.76*** |
| 502wx1 | 49.78*** | 52.62*** | 22.12*** |
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