Sucrose-Metabolizing Enzyme Activities in Response to Plant Growth Substances in Pigeonpea Genotypes

Pigeonpea (Cajanus cajan) is one of the most important pulse crops. Though the crop accumulates maximum biomass, a proportionally low final yield is obtained due to higher partitioning of dry matter towards vegetative growth and flower and fruit/pod drop. Therefore, there is a need to reduce the plant height and improve the source–sink relationship. In the present study, the effect of foliar spray of growth substances such as mepiquat chloride (200 ml/ac), ethrel (200 ppm) and stance (200 ml/ac) at 60, 60 + 75 and 75 days after sowing (DAS) on physiological parameters as well as on sucrose-cleaving enzymes in two pigeonpea genotypes (PAU 88I and AL 201) was investigated. It was observed that the foliar spray of ethrel @ 200 ppm (60 + 75 DAS) significantly decreased the height of PAU 881 and AL 201 by 16.07% and 15.04%, respectively. Higher activities of sucrose synthase (in leaves and stem) and invertase (in leaves, stem, pod wall and developing seed) were observed with ethrel (60 + 75 DAS) treatment in both genotypes. The foliar sprays of growth substances significantly reduced the plant height and improved the fruiting branches/pods, leading to enhanced yield irrespective of genotype. © 2018, The National Academy of Sciences, India.