Gamma ray induction of translocations in the corn earworm, Helicoverpa armigera (Hubner), (Lepidoptera: Noctuidae)
1997
Bella, A.P. | Jerusalem, G.L. | Barrion, A.A. | Ocampo, V.R. | De Leon, J.B. (Philippines Univ. Los Banos, College, Laguna (Philippines). Inst. of Biological Sciences)
Male pupae (pharate adults) of the corn earworm, Helicoverpa armigera (Hubner), were subjected to 100 and 150 Grey (Gy) of gamma irradiation. Karyological analyses of the normal homogametic male prepupae revealed diploid genomic complement 2n=62 (30IIA + ZZ), small homomorphic chromosome with mean relative length ranging from 0.022 to 0.044 and regular first meiotic behavior. The same were exhibited by the first generation progenies of the crosses between normal males and females. On the other hand, the progenies of matings involving normal females and 100 Gy or 150 Gy irradiated males possessed spermatocytes with heterozygous reciprocal translocations. These translocations appeared as chains and rings at diakinesis. At 100 Gy gamma radiation, the 900 spermatocytes of 30 first generation H. armigera exhibited 71.30 percent chain, 9.8 percent ring, 4.9 percent chain and ring and 14 percent normal; at 150 Gy gamma radiation, the spermatocytes showed 84.87 percent chain, 2.71 percent ring, 12.42 percent chain and ring and 1.67 percent normal. Thus, the inheritance of induced partial male sterility was inferred, translocations being markers of gametic infertility
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