Genetic diversity analysis of marigold (Tagetes sp) genotypes using RAPD and ISSR markers

The genetic diversity of 15 genotypes of Tagetes erecta L. (African marigold; Af/ws-1, Af/ws-2, Af/ws-3, Af/ws-4, Af/ws-5, Af/ws-6 and Af/ws-7) and Tagetes patula L. (French marigold; Fr/ws-1, Fr/ws-2, Fr/ws-3, Fr/ws-4, Fr/ws-5, Fr/ws-6, Fr/ws-7 and Fr/ws-8) were assessed using PCR based RAPD (Random Amplified Polymorphic DNA) and ISSR (Inter Simple Sequence Repeat) markers. Twenty three RAPD primers were used to generate polymorphism and mean per cent polymorphism was found as 57.72% ranging from 33.33% (OPF-2) to 83.33% (RAPD-07). Five most informative primers (OPA-02, OPA-04, OPO-10, RAPD-07 and RAPD-18) were identified on the basis of level of polymorphism detected by individual primer. Twelve ISSR primers were also used to generate polymorphism and mean per cent polymorphism was 60.48% ranging from 40.00% (ISSR-02, ISSR-17) to 90.00% (ISSR-03). The five most informative primers (ISSR-03, ISSR-06, ISSR-12, ISSR-31 and ISSR-18) were also identified on the basis of polymorphism. The dendrogram obtained from UPGMA cluster analysis of Jaccard's similarity values based on 23 RAPD and 12 ISSR markers grouped 15 genotypes into two clusters species wise (Tagetes erecta and Tagetes patula) which confirm the reliability of PCR based molecular markers. PCA analysis also confirmed the grouping of genotypes as they were present in same group as revealed by RAPD and ISSR markers.