Microscopic Characterization of the Cultivated and Wild Brassica Species: Cytological and Stomatal Analysis

Abstract

The Brassicaceae family comprises a wide array of diploid, amphidiploid, and wild species that serve as vital component for crop improvement and understanding plant genome evolution. This genus contains six different species in which there are three diploid species (Brassica nigra (genome BB; 2n= 16), Brassica oleracea (genome CC; 2n= 18) and Brassica rapa (genome AA; 2n=20) and three amphidiploids (Brassica carinata (genome BBCC;2n=34), Brassica juncea (genome AABB; 2n=36) and Brassica napus (genome AACC; 2n=38) species, which are derived from two diploid species. The present study aimed to examine the cytological analysis and analyse the stomatal features across 19 Brassica species, including both cultivated and wild types. The mitosis analysis were done and the chromosome number was counted for each species. The chromosomal parameters were analysed for cultivated and wild species and ideograms were preparade for respective species. Secondly, the stomatal analysis was performed, including the number of chloroplasts in each guard cell of leaf sample of each species. Image-based measurements revealed that amphidiploid species exhibited significantly higher chloroplast numbers and guard cell dimensions compared to diploid and wild species. Two-way ANOVA confirmed highly significant differences across species, traits, and their interaction. The pearson’s correlation coefficient (PCC) analysis showed that the chloroplast number is a marker for ploidy estimation. The findings will contribute valuable insights into Brassicaceae cytogenetics, supporting the application of these traits in species differentiation, ploidy determination, and utilization of the CWRs in Brassica crop improvement programs.