Cytogenetic analysis of somaclonal variation in regenerated plants of Berseem clover (Trifolium alexandrium L.)

Abstract

The potential of somaclonal variation was studied in Berseem clover (Trifolium alexandrinum L.) which is one of the important forage plants of Iran, cultivated in different regions of the country. Different tissue culture media and different sources of explants were used to regenerate plants. Petiole and inter-node explants were able to produce callus. Good callus growth occurred in the MS media having 2 mg/l NAA+ 30 gm sucrose. The calli of MS media having 0.5 mg/l NAA+0.5 mg/l KIN could produce plants. The roots were produced in the MS media having 0.1 5 mg/l BAP+1 mg/l IAA which were used for further analysis. Karyotypic analysis of Berseem clover showed the presence of 2n = 2x = 16 chromosome number having 7 pairs of metacentric and 1 pair of sub-metacentric chromosomes. The size of chromosomes ranged from 2 ±0.62 μm to 3.66 ±0.18. Cytogenetical analysis of the tissue culture regenerated plants showed the presence of different somatic chromosome numbers ranging from 2n = 16 to 2n = 48, the latter chromosome number only occurred in 12 weeks culture time-period. Partial or complete endomitosis may be the reason for the change in chromosome numbers observed.

Key words:

• berseem clover
• cytogenetics
• somaclonal variation