Effect of L-proline and L-glutamic acid on productivity of winter rapeseed

A higher level of fertilizers can have negative effects on the environment; therefore, selection of environmentally friendly preparations to increase plant productivity is very important. The aim of this study was to evaluate the effect of exogenously applied amino acids L-proline (30 mM L-1) and L-glutamic acid (1.5 M L-1) on the productivity of winter rapeseed (Brassica napus L. subsp. oleifera (Delile) Sinskaya) measuring number of siliques per plant, number of seeds per silique, 1000-seed weight, seed yield, crude fat content and crude fiber content. Treatments were applied at one or two growth stages of rapeseed. Higher 1000-seed weight and seed yield were obtained with L-glutamic acid in autumn and spring, while the higher number of siliques per plant was observed without amino acid application. Application of both amino acids led to an increase in seed yield of winter rapeseed from 3.5% to 11.8%. Principal component analysis showed that the first factor was highly and positively correlated with seed yield, 1000-seed weight, and crude fat and negatively with crude fiber, while the second factor was highly and positively correlated with silique per plant and negatively with seeds per silique. Higher values of crude fat content, seed yield, and 1000-seed weight were associated with application of glutamic acid on winter rapeseed, while crude fiber content was related to the application of proline. The study showed that higher 1000-seed, seed yield weight and crude fat content in seeds of winter rapeseed (P < 0.05) were obtained spraying plants with 1.5 M L-1 L-glutamic acid solution in autumn and spring.