Phenotypic Diversity and Morphological Performance Evaluation of Local Lotus (Nelumbo nucifera Gaertn.) Genotypes in Kerala, India

Abstract

The vast morphological diversity of Kerala’s indigenous Nelumbo nucifera Gaertn. genotypes makes suitable for waterscaping, floral arrangements, and sacred offerings. Despite these significant ornamental and functional attributes, the commercial, medicinal, and landscaping potential of these germplasms remains largely underutilized and requires systematic exploration. Hence, this study was aimed to evaluate suitability of local lotus genotypes for commercial purposes, specifically for landscaping and the loose flower trade in the floral market. Ten local lotus genotypes from various districts of Kerala were evaluated for their morphological performance. The experiment was conducted using a completely randomized design (CRD) with two replications per treatment. Significant morphological variations were identified through ANOVA and LSD tests, while cluster analysis categorized the germplasm based on phenotypic similarities.  Genotypes KAU Nn 6 identified as the most vigorous genotype, exhibited superior vegetative growth, with a plant height of 126 cm, maximum leaf production (14 leaves), and a leaf size of 41 cm and unique leaf pigmentation characterized by a red-edged margin. In contrast, KAU Nn 18 and KAU Nn 10 with compact growth habit (83 cm and 84 cm of plant height respectively) can be suggested to small ponds or pools for waterscaping due to their shorter plant height and specific structural attributes. From a floral perspective, the germplasm demonstrated significant phenotypic variability in flower type, bud shape, and color, which are essential for future crop improvement. KAU Nn 6 was particularly notable for its high flowering intensity, producing 12 flowers per year with flower production in dormant period also (November to January). Other genotypes such as KAU Nn 1 and KAU Nn 16 were double flowered types with distinct ovoid or conic bud shapes, but only single flower could produce during whole study period.  The diversity of flower bud colours ranging from green-yellow and green-purple to green-red and flower colour from pink to white or greenish white, further underscores the ornamental potential of these local genotypes since unopened flower buds are sold as loose flowers in floral market. KAU Nn 16 was found to be the premier ornamental choice for its exceptional flower diameter (28 cm) and rare double-white form. KAU Nn 5 exceled in producing the highest flower count (6 No’s) among double types, maximum petal density, and the earliest blooming cycle. Hierarchical cluster analysis and heat map visualization successfully categorized the ten lotus genotypes into three distinct groups based on their morphological and phenological traits. These findings highlight significant phenotypic diversity within the lotus germplasm of Kerala providing a framework for selecting superior genotypes for breeding and commercial waterscaping.