Effect of the Nitrate Reductase Genes (Nia) on the Quality of Different Lettuce Genotypes for Low Nitrate Content

Abstract

Genotypic variation in nitrate concentrations of different lettuce genotypes belonging to four types (Butterhead, Cos/Romaine, Crisphead, and Stem lettuce) and its relationship to nitrate reductase genes (Nia) for low nitrate concentrations of leaves was investigated. The results showed that the Romaine genotype ' Lobjoit's Green' exhibited the lowest leaf nitrate concentration (4877.7 mg/kg dry weight). The highest nitrate levels were recorded in the Butterhead genotypes 'Augusta and Kennedy'. Nitrate concentrations in the roots were significantly higher in the Romaine genotype ' Little Gem' and the Butterhead genotypes 'Augusta and Merveille Des Quatre Saisons' than the other lettuce genotypes. Total N concentrations were higher in the Butterhead and Crisphead genotypes than in the Romaine and Stem lettuce genotypes. A significant positive association (r = 0.80, p > 0.01) was observed between leaf NO