芥菜、苋菜是富集硝酸盐的蔬菜种类．在不同遗传型之间．硝酸盐含量差异可达１倍以上．硝酸盐含量是可遗传的数量性状，但遗传力很低．直接选择基本无效．通过对上述两种蔬菜各性状间的遗传相关及通径分析研究指出，选择生长速度快、叶片及分蘖数多、叶形大、叶片缺刻较浅、植株高大且单株重的植株可望获得低硝酸盐含量的芥菜类型．苋菜情况相反，叶柄短、植株紧凑，单株较轻且叶色淡的植株．硝酸盐含量较低． Mustard, amaranth is a nitrate-rich vegetable species. Between different genetic types. The difference of nitrate content can reach more than 1 times. Nitrate content is a heritable quantitative trait, but heritability is low. Direct selection of basic invalid. Through the genetic correlation and path analysis of the above two vegetables, it is pointed out that the plants with high plant height and single plant weight are expected to grow faster with more leaves and tillers, larger leaf shape, Mustard type with low nitrate content. In contrast, amaranth plants have short petiole, compact plants, light plants and pale leaves. Nitrate content is lower.