First nuclear DNA amounts in diploid (2n = 2x = 14) Corchorus spp. by flow cytometry: genome sizes in the cultivated jute species (C. capsularis L. and C. olitorius L.) are ∼300% smaller than the reported estimate of 1100–1350 Mb

Abstract

We report the 2C values (nuclear DNA content) and haploid genome (1C) sizes of the Corchorus species (2n = 2x = 14), with a special reference to the two cultivated jute species, viz., C. capsularis L. (the white jute) and C. olitorius L. (the tossa jute). Flow cytometric analysis of propidium iodide-stained nuclei showed that the 2C values were between 0.502 and 0.695 pg for C. capsularis, and between 0.643 and 0.718 pg for C. olitorius. For both the cultivated species, however, mutants had higher amounts of nuclear DNA than that of the cultivars. Amongst the wild Corchorus species, the lowest 2C value was observed in C. fascicularis (0.384 pg), while the highest in C. pseudo-olitorius (0.712). The current 2C values of both the cultivated jute species are in disagreement with earlier estimates of 2.3 and 2.8 pg in C. capsularis and C. olitorius, respectively. Of the Corchorus species studied, C. fascicularis has the smallest haploid genome (~188 Mb) followed by C. aestuans (~194 Mb). Our results show that, on an average, genome sizes (1C values) of C. capsularis and C. olitorius are ~280 Mb and ~324 Mb, respectively, which are ~300% smaller than their corresponding reported estimates. The white jute cv. JRC-212 (or Branca) has the smallest genome (~246 Mb) among the economically important crop species.