Interactive Effects of Plant Growth Regulators and Varieties on Morpho-florimetric Traits and Flower Yield of China Aster (Callistephus chinensis L. Nees)
Rakesh Kumar
Department of Floriculture and Landscaping, Bihar Agricultural College, Sabour-83210 (BAU, Sabour), India.
Shashi Ranjan Pratap Singh *
Bhola Paswan Shastri Agricultural College, Purnea-854302 (BAU, Sabour), India.
Paramveer Singh
Department of Floriculture and Landscaping, Bihar Agricultural College, Sabour-83210 (BAU, Sabour), India.
Jai Prakash Prasad
Bhola Paswan Shastri Agricultural College, Purnea-854302 (BAU, Sabour), India.
Ravi Ranjan Kumar
Bhola Paswan Shastri Agricultural College, Purnea-854302 (BAU, Sabour), India.
Anand Kumar Jain
Irrigation research Station, Bikramganj, Rohtas-802212 (BAU, Sabour), India.
J.N. Srivastava
Department of Plant Pathology, Bihar Agricultural College, Sabour-83210 (BAU, Sabour), India.
*Author to whom correspondence should be addressed.
Abstract
The combined effects of plant growth regulators (PGRs) and varietal selection are important for improving ornamental crop productivity; however, variety-specific responses to PGRs have been less systematically examined in China aster. This study evaluated seven exogenous PGR treatments (T1–T7) and three varieties (V1–V3) using a two-factor experimental design to determine their effects on growth, flowering and flower yield. Eleven morpho-florimetric traits were recorded and analysed using two-way ANOVA, Pearson correlation, principal component analysis (PCA) and scree plots. PGR treatments and varieties significantly affected (p < 0.001) most traits, including plant height, leaf dimensions, branches per plant, flowering duration, flower diameter, flower weight, flowers per plant and total yield. Significant treatment × variety interactions (p < 0.05) were observed for plant height, branches per plant and flowers per plant, indicating differential varietal responses to PGR application. The T3V3 combination produced the highest flower yield (13.43 t ha⁻¹), whereas T1V1 recorded the lowest yield (8.01 t ha⁻¹). Flower yield was strongly and positively associated with flowers per plant (r = 0.91), flower weight (r = 0.85), branches per plant (r = 0.69) and flowering duration (r = 0.68). PCA indicated that the first two principal components explained more than 75% of the variance, with branches per plant, flower weight and flowers per plant contributing prominently to yield. These findings suggest that PGR recommendations for China aster should consider varietal responsiveness.
Keywords: China aster, Callistephus chinensis, gibberellic acid, naphthalene acetic acid, plant growth regulators, varietal response, morpho-florimetric traits, flower yield, treatment × variety interaction, principal component analysis