Karyotypic and Nuclear DNA Variations in Lathyrus sativus (Fabaceae)

Abstract

Karyotypic studies were performed on 20 grasspea (Lathyrus sativus L.) genotypes (15 genotypes from ICARDA and 5 from Iran) labeled G1-G20. All genotypes examined were diploid (2n = 2x = 14), having mean chromosome length (TL) of 6.03 μm (4.7–6.7 μm) and total chromosome volume mean (TCV) of 24.2 μm3 (18.1–35.1 μm3). The largest value of chromatin length was detected on G8 (93.3 μm) while G3 demonstrated the smallest value (65.2 μm). Karyotype formula was determined as “14m” in 19 genotypes and “12m + 2sm” in G20, using Levanet al. chromosome nomenclature. Satellite numbers varied between 1 to 2 pairs. Karyotypes were classified as 1A of Stebbins classification. The scatter diagram of A1 and A2 asymmetry indicated 5 groups of genotypes: G2 and G19 with the most asymmetrical and symmetrical karyotypes, respectively. Results of multivariate analysis and scatter diagram of TL with CI indicated 3 groups of genotypes according to their chro- mosomal parameters. Flow cytometric studies were performed, using PI staining method and Pisum sativum cv. Ctirad (2C DNA = 9.09 pg) as a reference standard. The mean 2C DNA content of all genotypes was 14.7 pg, ranging from 13.8 pg (G1) to 15.6 pg (G20). Significant positive correlations were found between 2C DNA content and either stomatal cell area or longitude. © 2011 Taylor and Francis Group, LLC.