THE INFLUENCE OF SOWING DATES ON THE YIELD OF ROMAINE (LACTUCA SATIVA VAR. LONGIFOLIA) UNDER THE CONDITIONS OF UZBEKISTAN

Abstract

Research was conducted at the Scientific Research Institute of Vegetable, Melon Crops and Potato (Uzbekistan) in 2024–2025 to study the effect of sowing dates on the productivity of romaine lettuce (Lactuca sativa var. longifolia) varieties in comparison with leaf lettuce (Lactuca sativa L.). The experiment included five sowing dates: February 20, March 1 (control), March 10, March 20, and March 30, with a planting scheme of 70×30 cm. It was established that the onset of the technical ripeness phase depends on sowing dates and accelerates when shifting from early to later dates in the spring period. To obtain early bunched produce, sowing on February 20 provided a yield of leaf lettuce of 1.37 kg/m² and romaine varieties of 2.19–2.43 kg/m². Compared to the control (March 1), maximum yield was noted for sowing on March 10: for leaf lettuce variety Kok shokh – 1.82 kg/m², for romaine varieties Korolevskiy pir and Quintus – 2.89–3.15 kg/m², which enhances their agricultural value for cultivation..