Impact of genotype and micronutrient applications on nitrate reductase activity of tea leaves

Tea flush shoots comprising three leaves and a bud were collected from various clones (cultivars) from different experimental fields and analysed for nitrate reductase (NR) activity. Most of the cultivars of Assam type had higher NR activity, followed by Cambod and China types. NR activity was maximum in the clone UPASI-9. It was found that NR activity could be used as a biochemical tool to predict the yield potential of cultivars at the initial stage of selection for a breeding programme. The activity was higher in the youngest part of the tea plant. With the existing methodology it was not possible to measure the NR activity in stem portions of the tea plant. There was a strong positive correlation between NR activity and amino acid contents of tea shoots. Inclusion of molybdenum in the foliar applied micronutrient mixture was found helpful in triggering the NR activity in a few clones and seedlings. Copyright