Assessing karyotype diversity in the genus Lathyrus L. (Fabaceae)

Abstract

Although substantial information on the karyological measures of Lathyrus is available, no study has collected and analysed such data to assess the relationship among its taxa. Hence, the present study examined the degree and trends of chromosome diversity in this genus in congruence with Kupicha's sectional classification. Karyo-morphological data for 74 species representing 11 sections of Lathyrus were collected through the literature survey. The karyological measures included were the total haploid chromosome length (THL), somatic chromosome number (2n), basic chromosome number (x), and five other parameters of karyotype asymmetry (CV_CL, CV_CI, M_CA, A₁, and A₂). Basic chromosome number (x = 7) and somatic chromosome number (2n = 14) remained stable throughout the genus. Mean karyotypes revealed marked variations in karyotype structure among the 11 sections of Lathyrus. Further, key differences were identified during comparisons of various measures of karyotype asymmetry. Phylogenetic and principal coordinate analyses exhibited substantial variation among different sections of Lathyrus and out-group genera. Overall, current findings indicated that the karyotype asymmetry measures can serve as an efficient tool to assess the relationship among different sections of Lathyrus.