Comparing methods for controlled capture and quantification of pollen in Cannabis sativa

PREMISE: Precise pollen collection methods are necessary for crop breeding, but anemophilous pollen is notoriously difficult to capture and control. Here we compared a variety of methods for the controlled capture of cannabis pollen, intended to ease the process of cross‐fertilization for breeding this wind‐pollinated plant, and measured the utility of light spectroscopy for quantifying relative pollen yield. METHODS AND RESULTS: In two independent trials, we compared a control method of pollen collection (hand collection) to either vacuum‐, water‐, or bag‐collection methods. We used visible light spectroscopy to quantify relative pollen yield, and validated this approach using microscopic pollen counts. We determined that pollen yield was highest when using hand collection or vacuum collection, but efficiency did not differ significantly among methods. CONCLUSIONS: To maximize yield, pollen should be collected by hand or vacuum, but all collection methods were equally efficient in a relative sense because yield increased with collection time. We also found that light spectroscopy is an accurate and rapid method of quantifying pollen abundance (R (2) = 0.86) in a liquid suspension.