Selection of potential pollinizers for ‘Hass’ avocado based on flowering time and male–female overlapping

Avocado production is dependent on the singular synchronous protogynous dichogamy of the species that promotes outcrossing. With the objective of selecting potential pollinizer avocado genotypes for ‘Hass’, the most important avocado cultivar worldwide, we have monitored during two consecutive years the flowering phenology of 27 avocado genotypes in South-eastern Spain. The average length of the flowering season was 45 days ranging from 18 days for ‘Harvest’ to 50 days for ‘Fuerte’. The earliest genotypes to flower were ‘Fuerte’ and ‘Shepard’ that started blooming during the third week of March. The latest genotypes to flower were ‘Colin V-33’, ‘Adi’, ‘OA184’ and ‘Harvest’, which started blooming in the second week of April. ‘Hass’ blooming lasted 30 days, from the first week of April until the second week of May. Since a good pollinizer must present not only an overlapping in the flowering season but also an overlapping in sexual stages with the pollinated cultivar, a group of 12 genotypes (‘Hass’, ‘Fuerte’ and 10 genotypes producing ‘Hass-like’ fruit with good overlapping in the flowering season with ‘Hass’) was studied with more detail determining daily the stages of male and female overlapping every 2 h. Results herein indicate that ‘Marvel’ and ‘Nobel’ showed a high sexual overlapping with ‘Hass’. Taking into account the flowering phenology, the overlapping in sexual stages and the fruit set obtained with hand-pollinated flowers in the field, those two genotypes could be an interesting alternative to the current use of ‘Fuerte’ as pollinizer for ‘Hass’ in South-eastern Spain.