Ex-situ evaluation of genetic diversity in indigenous Nerium accessions

Abstract

In the current investigation, 22 Nerium accessions gathered from different places in Tamil Nadu were evaluated. Regarding the assessment of accessions, a higher plant height of 209.25 cm was recorded in NI-13, and the greatest number of shoots per plant (7.40), plant spread in East-West direction (118.15 cm) and plant spread in North-South direction (123.85 cm) occurred in NI-16. The highest average leaf length (28.60 cm) was seen in Accession NI-1, whereas Accession NI-6 had the largest average leaf width (3.25 cm). Among the accessions, NI-13 recorded earliness in bud initiation (66.60). Accession NI-1 had the most flowers per spike (18.15), whereas accession NI-16 had the longest blooms (4.70) and highest individual flower weight (0.96 g) was recorded in the accession NI-3. Flower yield was highest in the accession NI-15 (4.10 kg) and the retentivity of the flowering rate were noted to be elevated in accession NI-1 (3.25 days). The PCA analysis revealed that four principal components showed 75.44% of total variation. From this, we identified that plant height, No. of shoots, plant spread (East-West) and plant spread (North-South), internode length, No. of spikes yield/plant/year, flower weight, and leaf width in different principal components are highly contributing traits for total variation. The clustering pattern was very effective, with a cophenetic correlation coefficient 0.705. The cluster analysis was displayed in four major clusters based on their specific geographical locations. The above-found accessions and traits could be utilized in the nerium varietal improvement programmes.