Determination of intraspecific nuclear DNA content variation in common vetch (Vicia sativa L.) lines and cultivars based on two distinct internal reference standards

Abstract

The 2C nuclear DNA contents of 40 common vetch (Vicia sativa L.) lines and cultivars were determined by using both safflower (Carthamus tinctorius L.) and barley (Hordeum vulgare L.) as internal reference standards in flow cytometry analysis and correlated with plant morphological characters and 1000-seed weight. The t-test results showed a significant difference between the mean DNA values of the barley and safflower standards (t = -16.74, P = 0.0001). Data analysis also indicated significant (P < 0.01) intraspecific nuclear DNA content variation within the common vetch lines and cultivars for both internal standards used. The DNA content values ranged from 3.342 pg to 3.652 pg and from 3.600 pg to 4.002 pg for the internal standards of safflower and barley, respectively. The DNA differences within the internal standards were 0.310 pg and 0.402 pg for safflower and barley, respectively. The internal standard of barley constantly produced higher DNA content values than the values of safflower standard for all vetch lines and cultivars. Nuclear DNA content differences between 2 internal standards for the same plant material reached as high as 15.59% (0.540 pg), which is equivalent to 528.12 Mbp DNA. No significant correlations between 1000-seed weight and the nuclear DNA contents of barley (P < 0.51) or safflower (P < 0.76) were detected.