Morphology and Fertility of Pollen of Avocado (Persea americana MILL.)

Abstract

1) Studies on the pollen morphology and fertility in four cultivars of Avocado (‘Zutano’, ‘Bacon’, ‘Fuerte’and‘Mexicola’) using scanning electron microscope (SEM) and optical microscope were carried out from 1986 to 1987 in Japan.
2) The dried pollen grains were mainly spherical in shape with a thorny or granular surface depending on the cultivars, and they were binucleate. Based on microscopic observations, no germ pores was delicated on the surface of the pollen grains.
3) The fertility rate during flowering was higher than that before flowering for each cultivar, and it was higher in‘Fuerte’, followed by‘Zutano’, ‘Bacon’and‘Mexicola’in this order.
4) The size of the pollen grains of all the cultivars ranged from 25 to 72μm in diameter, and the fertile pollen grains were larger than the sterile (infertile) ones.
5) The number of pollen grains of the fertile pollens reached a peak when the pollen grains model sizes of 44μm, 39μm, and 37μm for‘Fuerte’, ‘Zutano’, and‘Bacon’, respectively, and no peak was observed in‘Mexicola’. Additionally, the higher fertility rate and the larger the grain size of pollen the higher the fruit yield of the cultivars.