Cytophotometric Estimation of Nuclear DNA in Different Species and Varieties of Agave

Abstract

Several taxa have recently been subjected to nuclear DNA estimation through cytophotometry (Iyengar and Sen 1978, Ohri et al. 1981, Resslar et al. 1981, Sharma and Chattophadhyay 1983, Sharma and Mukhopadhyay 1984, Mukhopadhyay and Sharma 1984). Such in situ estimation often provides a distinctive parameter for species differentiation (Chooi 1971, Ayonoadu 1974, Bennett et al. 1977, Rees et al. 1978, Raina and Rees 1983, Seal 1983, Sharma and Mukhopadhyay 1984). However, cases are also on record where the DNA values vary even at an intraspecific level (Miksche 1971, Furuta et al. 1975, Narayan and Rees 1976, Price et al. 1980, Sharma and Chattopadhyay 1983). In this regard, the role of repetitive fraction has been emphasized by different authors as well (Bullen and Rees 1972, Rees and Jones 1972, Rees et al. 1979, Resslar et al. 1981). The nuclear DNA estimation in Agave, a steroidal sapogenin yielding plant growing widely in India, was thought desirable in view of the commercial importance of this group as well as indication of cytological races already observed in this genus (Chattopadhyay 1983). Nine different species and varieties of Agave were subjected to the present investigation where the amounts of 4C nuclear DNA were estimated through in situ cytophotometric method and its correlation, if any, with different cytological parameters was analysed. © 1987, Japan Mendel Society, International Society of Cytology. All rights reserved.