Agronomy and Horticulture Department


Date of this Version



Published in Genetics (1958) 43: 728-736.


Comparisons of the biological effects of X-rays and thermal neutrons on dormant seeds of barley have been made by seedling height studies, root tip cytological analyses, and cytological studies of pollen mother cells in the first generation following irradiation and by seedling mutation studies the second generation after irradiation. The results of these studies have been reported by Caldecott, Frolik and Morris (1952) and Caldecott, Beard and Gardner (1954). The objective of the research reported in this paper was to extend the comparison of these two types of radiation by studying their effects on dormant seeds of four widely different crop species: barley (Hordeum vulgare L.), maize (Zea mays L.), mustard (Brassica juncea Coss) , and safflower (Carthamus tinctorius L.).