Cytological study in some species of Lactuca L. (Asteraceae) from high altitudinal regions of Kinnaur district, Himachal Pradesh, India

Cytological study in some species of Lactuca L. (Asteraceae) from high altitudinal regions of Kinnaur district, Himachal Pradesh, India

The Present study includes cytomorphological analysis on five species of Lactuca L. (Asteraceae) from the hilly district of Kinnaur, Himachal Pradesh (India). Lactuca orientalis (Boiss.) Boiss. (2n=18) which has been counted chromosomally for the first time from India also adds a new intraspecific 2x cytotype to the earlier tetraploid chromosomal report of (2n=36) from outside of India. The chromosome counts for L. dissecta D. Don (n=8), L. dolichophylla Kitam. (n=8), L. macrorhiza (Royle) Hook. f. (n=8) and L. serriola L. (n=9) confirm the earlier reports from India and other parts of the world. The wild accessions of L. serriola L. from the region exhibit considerable morphological variability in leaf characters but shared the same diploid chromosome number (2n=18). Such variation in morphological characters where morphovariants grow under similar ecological condition could be attributed to genetic reasons. Meiotic analysis reveals that chromosomes are small-sized in L. dissecta, and L. dolicophylla compared to L. macrorhiza, L. orientalis and L. serriola which possessed larger sized chromosomes. Besides, L. orientalis and L. serriola depict relative differences in the size of bivalents in a genome which could be attributed to unequal reciprocal translocations.