• Evaluation of Air Threshing for Small Lots of Winterfat Fruits

      Booth, D. T.; Griffith, L. W. (Society for Range Management, 1984-05-01)
      Air threshing, using an air gun scarifier, is an improved method for threshing small lots of winterfat [Eurotia lanata (Pursh) Moq.; Ceratoides 1. (Pursh) J.T. Howell] fruits for laboratory analysis. The technique is faster than hand threshing and causes insignificant damage to the seed in contrast to hammer mill threshing which damages about 25% of the seed.
    • Threshing Damage to Radicle Apex Affects Geotropic Response of Winterfat

      Booth, D. T. (Society for Range Management, 1984-05-01)
      The acute end of a winterfat [Eurotia lanata (Pursh) Moq.; Ceratoides 1. (Pursh) J.T. Howell] seed is formed by the apex of the radicle and of the cotyledons. It is postulated that this shape makes the embryo root cap especially susceptible to damage during threshing and that such damage is the cause of a high percentage of threshed germinated seed (germinant) lacking positive geotropism. This study consisted of examining germination behavior and post germination anatomy of the root apex of germinants with and without positive geotropism. The radicle apex was found to be damaged in 25% of the threshed seed. Eighty-five percent of the germinants from undamaged seed had positive geotropism as compared to 53% from the damaged seed. The latter had a range of anatomical aberrations in which the root cap was missing or seriously abnormal. It is concluded that the standard method of hammer mill threshing of winterfat fruits results in 25% of the seed sustaining damage to the radicle apex. This damage causes a loss of root cap functions, particularly the sensing of gravity. It is recommended that plantings be made by broadcasting whole fruits, rather than by drilling threshed seed.