VARIATION IN CHEMICAL COMPOSITION OF LUCERNE VARIETIES IN CONDITIONS OF WATER DEFICIENCY STRESS (original) (raw)

Variation in chemical composition of four Bulgarian lucerne varieties (Prista 2, Obnova 10, Dara and Pleven 6) was studied in conditions of optimum moisture (75-80% WHC) and water deficiency stress (37-40% WHC). The trial was carried out in pots in the greenhouse of the Institute of Forage Crops, Pleven (2006-2007) and was laid out on a total background of nitrogen, phosphorus and potassium fertilizing. It was found that under water deficiency stress the content of crude protein increased in top biomass, as well as in roots of plants. In the top biomass, the greatest increase was found for variety Dara- by 7.8%, and in the roots- for variety Prista 2 by 17.2%. Under water deficiency stress, the nitrogen content in the yield of dry top biomass decreased for all tested varieties, being the slightest for variety Dara. Only for variety Dara, the values of Ca and P content were very close at both levels of water supply. On average, the plants of variety Prista 2 (0.2509) had the lowest index of sensitivity to water deficiency stress, followed by those of variety Dara (0.2595). Key words: lucerne varieties, water deficiency stress, crude protein, calcium, phosphorus, index of sensitivity to water deficiency stress