Comparative study of lettuce cultivars under out of season production

Ivanka Mitova, Nidal Shaban

Abstract: Lettuce (Lactuca sativa L.) is one of the oldest vegetable crops. Due to its valuable nutritional, dietetic and healing properties grown in the middle Ages. Salad as a vegetable culture found in almost all countries. The largest areas occupy in Europe, North America and New Zealand. On alluvial-meadow soil in conditions of field experience with spring cultivation, a study achieved with 19 varieties of head lettuce (Lactuca sativa var. Capitata) type Batavia (Batavia). Studies were conducted on 19 lettuce varieties in the Educational experimental field of the University of Forestry, located in the region of Sofia field. The plants were planted at three different conditions with three repetitions without treatments (three types of greenhouses – two unheated greenhouses and low tunnel covered with a polymer foil).The influence of soil and climatic conditions on the growth indicators and some of the indicators characterizing the quality of the production has been established. According to the indicator, mass of plants during harvest in the phase of technical maturity, lettuce plants arranged in nine homogeneous groups. The highest plant masses at the end of the study reported in the varieties Funride - 294.1 g/plant and Florine - 266.4 g/plant or 46.6% and 32.8% larger than the average weight (200.6 g/plant) for the experiment. At a confidence level of 95.0%, the experimental varieties are divided into 10 homogeneous groups according to the indicator number of leaves, as the variety Isi-45194 has the largest number - 54.4 leaves in its rosette. The measured nitrate content in the leaf mass of lettuce varieties is below the permitted concentrations for spring cultivation and ranges between 277.6 mg NO3-/kg fresh weight in the Hettie variety and 1248.0 mg NO3-/kg and 1234.8 mg NO3-/kg in the varieties Satine and Kriska. The nitrate nitrogen content is also low - between 6.9% (Aquarel variety) and 19.9% (Satine variety).

Keywords: mass of plants; nitrates; plastid pigments; salad varieties; total sugars

Date published: 2022-05-30