Seasonal variation in chiasma frequency among three morphotypes of Eclipta alba

Abstract

Natural variation in recombination frequency in Eclipta alba has been assessed by analyzing chiasma frequency variation among three morphologically diverse morphotypes i.e. erect, intermediate and prostrate. The study revealed that the chiasma frequency varied between 18.8-21.4, 18.9-20.9 and 19.3-21.7 in the three morphotypes, respectively. It is found that the chiasmata frequency for prostrate type remain higher throughout the year in comparison to intermediate and erect types. There was no signifi cant variation in mean chiasma frequency between plants within accessions, but there was signifi cant variation between accessions. Presently observed the cyclic variation in the average chiasma frequencies, recombination index and excess chiasma in the three morphotypes of Eclipta alba clearly depict the infl uence of environmental factors on the process of recombination.