While I was checking pecan budbreak, I cut shoots from two popular pecan cultivars (photo at right). These two cultivars represent the two flowering types pecan cultivars can exhibit. Kanza is a protogynous cultivar, meaning that female flowers become receptive before pollen is released. Hark is protandrous which means that pollen is shed before pistillate flowers become receptive. These two cultivars will pollinate each other. The early pollen shed by Hark will pollinate the early female flowers set by Kanza. Later in the pollination season, Kanza pollen will be released just in time to pollinate the late female flowers on Hark.
During bud break you can already see clues to the flowering habit of any cultivar. The catkins of protandrous cultivars will be large and fat right at bud break. In contrast, the catkins on a protogynous cultivar at this time of year will be small and thin. One close up look at the photo and you can easily see the difference. Remember, you can click on any photo in this blog to get a larger image of that photo.