Genetic Variability and Interrelationships among Morphological and Agronomical Characteristics in Rhizome Lotus (Nelumbo nucifera Gaertn.ssp.nucifera) Germplasms

Rhizome lotus (Nelumbo nucifera Gaertn.ssp.nucifera) has been cultivated for more than two thousand years as a food in China.The genetic variability in sixty-eight rhizome lotus germplasms from different regions of China,were evaluated using nineteen morphological characteristics.The associations of whole rhizome weight (TW) with main stem weight (MW),main stem length (ML),and width of the main stem section between the third and fourth knot (RW) were positive and highly significant.The path analysis revealed that MW had the highest positive direct effect on TW (0.982).Four principal components analyses (PCA) accounted for 77.33% of the total variability.Characteristics that showed high negative direct effect on TW were MW/TW (-0.296).A cluster analysis based on the morphological characteristics revealed five continuous groups according to evolutionary direction.