Assessment of pollen viability of some sweet cherry cultivars used in plant breeding in Extremadura, Spain

Pollen performance depends on several factors, one of which is pollen germination capacity. Pollen germination on stigma is an essential event for proper fertilization in seed producing plants. In the context of plant breeding, it is of great importance to assess pollen viability of the different cultivars involved in breeding in the first stages of the program, and thus optimize resources. In this work we have analyzed the pollen viability of pollen from sweet cherry cultivars intended to be used in obtaining new cultivars to secure a suitable positioning of cherry in the coming decades in Extremadura. Through in vitro culture, staining, and microscopy methods we assessed the pollen viability of 16 cherry cultivars from two different collections. At the same time, we attempted to identy differences in the pollen viability of the same cultivars from both locations (a traditional cherry cultivation place and a much warmer and dryer field) and tried to link them to an eventual global warming scenario. Different germination percentages were found among both approaches, in different cultivars located in the same place and the same cultivars from two different locations. The cultivars '7-91-C', 'Celeste', 'Sweetheart' and 'Van' reached the higuest pollen germination levels in both locations, being therefore suitable cultivars to use in a regional breeding program.