Analyses morphologique, cytogénétique et moléculaire du Lens culinaris Medik(Ssp Macrosperma et Microsperma)

Abstract

Lentil (Lens culinaris), one of the main food leguminous crops grown in Algeria. The objective of this work is the evaluation of the genetic variability of 12 cultivars through agro-morphological, cytogenetic, biochemical and molecular approaches. Many works are carried out at different levels (plant, seed, cell, chromosome, protein and DNA). This work consists of studying the agro-morphological characterization carried out on 15 quantitative parameters, establishing a detailed cytogenetic study (karyotype analysis, NORs, Nbanding and C-ban ding, meiosis and palynology), biochemical analysis to highlight protein content by SDS-PAGE technique. At the same time, a molecular characterization carried out using seven proposed microsatellite markers. The Idlep3 and Flip90-31 cultivars revealed a high yield potential and the existence of a significant difference according to the morphological parameters which explain a significant inter-genotypic variation, the PC1 (F1) and PC2 (F2) scores are calculated as 36 .87 and 21.93% of the total variance, respectively. According to the ascending hierarchical clustering, the analysis revealed five major groups with differentiation of seed types (Macrosperma and Microsperma). Cytogenetic results show regularity between mitosis and meiosis. The karyotypes are symmetrical. a positive correlation is demonstrated between the level of heterochromatin and the number of NOR. from bands C and N. Our results are original, dismaying the determination of marker chromosomes 1,2,3,4, while chromosomes 5,6,7 do not have any. Also note, the presence of satellites and type B chromosomes (euchromatic and heterochromatic), in this case, could be explained as a manifestation of their adaptation. In addition, we observed meiotic abnormalities and the existence of variability by studying the biometric characters of pollens of different cultivars, which reflects the great diversity. Polymorphism of the protein banding pattern (84%) revealed inter-genotypic variability. The gel obtained showed forty bands ranging from 13 to 21 with a molecular weight of 10 to 120 KDa. The Idlep3 genotype is characterized by specific bands, followed by the Flip90-31 cultivar. A large genetic variability characterizes lentil genotypes. The number of alleles per locus ranges from 2 (SSR317-1) to 6 (SSR19,SSR 151) and the PIC index ranges from 0.42 to 0.75. The frequency of the most common allele at each locus ranges from 42% (SSR317-1) to 75% (SSR28, SSR19). Based on the 44% genetic similarity coefficients, the dendrogram analysis revealed a large diversity observed among the cultivars, and it separates the cultivars into five groups. Note that there is no relationship between the geographical origin of the cultivars and the genetic distance. The genetic relationship discovered in this study could form the basis of future systematic lentil breeding programs. The Idlep3,Dahra and Flipe90-31 cultivars show the highest yields and are characterized by specific bands (or specific markers), which suggests that they are the most suitable cultivars. Therefore, we can offer them to agronomists to use them in lentil crosses for plant breeding