Ledebouria Roth is a complex genus and it shows a wide range of chromosome counts. Present paper reports chromosome number 2n (6X) = 90 in L. revoluta (L.f.) Jessop a number that is not known so far in the entire genus Ledebouria which exhibits highly asymmetrical (2C) karyotype. The karyotype symmetry of the chromosomes and extreme level of polyploidy indicates that the L. revoluta is actively evolving in varied climatic and geographical regions.
Two diploid mulberry varieties namely, V1 and M5 have been analyzed for detailed meiotic studies. Based on the chromosome configuration and other meiotic behavior x = 14 have been considered as basic number of the genus Morus. Meiosis shows marginal differences. Various meiotic abnormalities like occurrence of one mega chromosome pair at diakinesis, chromosomal bridge and chromosomes grouped more than four poles at anaphase II have been observed.
Seeds of Pisum sativum L. were treated with different doses (5, 10, 15, 20, 25, 30, 35 and 40 kR) of gamma rays. Three translocation heterozygotes were observed at meiotic division in a population raised from 20, 25 and 30kR treated seeds. The induced translocations showed a ring or chain of 4 chromosomes and 5 bivalents in most of the cells at diakinesis/metaphase I. The orientation of ring and chain quadrivalents predominantly showed the alternate type of orientation. The induced mutants showed delayed flowering, low flower number, low pod number as compared to control plants. The highest doses of gamma rays such as 35kR and 40kR caused death of all seedlings and no seed germination was observed.