RELATIVE BIOLOGICAL EFFECTIVENESS OF HEAVY PARTICLES FROM THE REACTION <sup>10</sup>B(n, α) <sup>7</sup>Li FOR CYTOGENETIC EFFECTS IN A PLOIDY SERIES OF THE GENUS <i>TRITICUM</i>

Abstract

Seeds of T. monococcum (2X), T. durum (4X) and T. aestivum (6X), with and without enrichment of 10B were exposed to thermal neutrons or X-rays. The RBE values of heavy particles from 10B (n, α) 7Li reaction compared with X-rays were determined at each ploidy level for reductions in seedling height and seed setting in the M1 generation and also with respect to induction of chlorophyll mutations in the M2 generation. The RBEs reported here are generally lower than those reported earlier for the use of re-dried seeds. Although no definite relationship was found between RBE values and ploidy levels, thermal neutrons were very effective in 10B-enriched seeds with respect to induction of chlorophyll mutations even in the hexaploids. There was a positive relation between the occurrence of the M1 spike mutations and of chlorophyll or skipe mutations among their progenies, especially in thermal neutron treatments of 10B-enriched seeds. The relative biological effectiveness and the tolerance of the polyploids were discussed and compared with other results reported in the literature.