Differential response of inbred and F1 hybrid embryos of Hibiscus sabdariffa L. to x-irradiation

Radio-response of HS 4288, HS 7910 and two F1 hybrid embryos of H. sabdariffa to X-ray doses (2-8 kR) was assessed. Reduction in shoot and root length and incidence of root injuries increased always with the increase of X-ray doses. LD50 values of HS 4288, HS 7910, F1 HS 4288 x HS 7910 and F1 HS 7910 x HS 428 were in between 5 and 6 kR, 2 and 4 kR, 6 and 8 kR, and 5 and 6 kR respectively. Judging by LD50 values and 100 per cent seedling abnormality, relatively HS 4288 and F1 HS 4288 x HS 7910 were resistant and HS 7910 and F1 HS 7910 x HS 4288 were susceptible. Induction of macro-mutations was different in two inbreds and also in two F1 hybrids. Role of cytoplasmic factors for the differential response are discussed. (author). 14 refs., 5 tabs