Comprehensive Analysis of Genetic variability, Trait interactions and Phenotypic diversity in Marigold (Tagetes spp.) genotypes

Marigold (Tagetes spp.) is a popular ornamental plant known for its vibrant flowers. This
study evaluates genetic variability and correlation among key morphological traits affecting
flower yield in 38 marigold genotypes. Significant differences were observed across all traits,
indicating substantial variability within the genotypes while phenotypic coefficient of
variation exceeded genotypic coefficient of variation for all traits, suggesting environmental
influence on trait expression, though genetic factors remained dominant. Heritability
estimates were high for most traits, with number of ray florets per flower exhibiting highest
heritability (99.12%) coupled with highest genetic advance (121.24%), indicating that
selection for this trait is likely to result in substantial genetic improvement. Correlation
analysis revealed significant positive associations between flower yield per plant and traits
such as plant height (0.453), fresh flower weight (0.582), and number of flowers per plant
(0.414) at both genotypic and phenotypic levels. Path coefficient analysis highlighted fresh
flower weight and number of flowers per plant as key determinants of yield, with direct
positive effects of 1.267 and 0.988, respectively at genotypic level. Principal component
analysis identified first three principal components explaining 74.61% of total variability,
with days to flower initiation (PC-I), fresh flower weight and flower diameter (PC-II), and
number of flowers per plant (PC-II) contributing most to observed variation. The study
suggests that selection for these traits, especially fresh flower weight and number of flowers,
could significantly enhance marigold productivity in future crop improvement efforts. It
addresses complexity of trait interactions, offering key insights for genetic improvement.