Pigeonpea (Cajanus cajan (L.) Millspaugh) genotypes (twelve), of which were divided into three groups based on the duration for flower initiation i.e. Short duration (ICPL151, ICPL87, ICPL1, ICPL6), Medium duration (T21, HY2 mutant, Pusa agheti, C11) and Long duration (ICPL270, ST1, PDM1, LRG30) were selected and was raised at the Experimental Farm of the Department of Botany, Andhra University, Waltair, Visakhapatnam, A.P., India for the present investigation on different enzymes like Malate dehydrogenase, Glycolate oxidase, Total chlorophyll content, Photosynthetic rate, Ribulose bisphosphate carboxylase activity and Phosphenolpyruvate carboxylase of the 10th leaf at three selected phases of crop growth i.e. vegetative, flowering and seed maturation phase. The malate dehydrogenase activity recorded an increase from the vegetative to flowering phase followed by a decrease at the seed maturation phase. In all the genotypes glycolate oxidase activity of the 10th leaf exhibited an increase at the flowering phase followed by a decrease at the seed maturation phase. Total chlorophyll content was gradually decreased with age in all the genotypes. The photosynthetic rate was decreased from vegetative to seed maturation phase in all the genotypes. The greatest fixation rate was observed in the ICPL87 of short duration genotypes and the lowest rate was observed in the ST1 of long duration genotypes. The ribulose bisphosphate carboxylase activity was decreased from vegetative phase to the seed maturation phase. Among the genotypes the ICPL87 of short duration and the ST1 of long duration genotypes recorded the maximum and minimum values respectively at the vegetative phase of crop growth. Phosphoenolpyruvate carboxylase activity of the genotypes increased from vegetative to flowering phase followed by a decline on the seed maturation phase. The enzyme activity recorded greater values on reaching the flowering phase.
