(1) Early microsporogenesis events are important to establish the shape of the tetrad, the polarity within the tetrad and consequently to determine the aperture pattern of the pollen grain.(2) Early in meiosis, each pair of homologs comes together to form a tetrad containing two pairs of sister chromatids.(3) a tetrad of distinct elements(4) Two-thirds of the tetrads gave rise to four normally growing spores and one spore that formed a microcolony of 10 cells.(5) In both strains, haploid phenotypes from tetrads yielding four viable spores may be used to measure the strength of crossover interference.(6) Sterile plants produce microspores aborted in tetrads , no visible pollen shed, and parthenocarpic pods bearing no seeds.
