Analysis of genetic, developmental and spatio-temporal patterns of nitrate accumulation in cauliflower and cabbage genotypes

Vegetables, an essential constituent of the human diet, are regarded as reservoirs of nitrate. The nitrate worries are attributed to the irrational and unscientific use of nitrogen fertilizers. An experiment was performed to examine the genetic, spatial, temporal and developmental variations in nitrate accumulation patterns in cauliflower (sixteen genotypes) and white cabbage (eleven genotypes). Test plants were supplied with varying levels of nitrogen (0, 60, 120, 180 kg N ha −1 ) or 60 + 40 kg N ha −1 (split application). Nitrate content, nitrate reductase (NR) activity and SPAD value for chlorophyll level were examined in different organs of all genotypes of test plants at various growth stages and time periods. The nitrate content showed a significant variation among the genotypes and was highest in VRCF-427 and the lowest in Pusa Deepali genotype of cauliflower; whereas in cabbage genotype Early Golden Acre and Pusa Drumhead were identified as the high and low nitrate accumulating genotypes respectively. In all the genotypes of both the test plants, a negative correlation was found between NR activity and nitrate content, which showed an age-dependent increase, being the highest at marketable yield stage, thus posing a serious concern.