INFLUENCE OF PLANTING SPACES ON GROWTH, YIELD AND BACTERIAL SOFT ROT INFECTION OF LETTUCE (Lactuca sativa L.)

Abstract

The experiment was conducted to evaluate the growth, yield, and bacterial soft rot infection of Lettuce (Lactuca sativa L.) in the organic system of the multi- span house without chemical fertilization and without heating, planting was in different planting spaces. The research was directed from 14th November (sowing seeds in the nursery) 2018 to 14th of March 2019 (harvesting). The experiment was designed in randomized complete blocks (RCBD), with eight treatment planting spaces 10, 15, 20, 25, 30, 35, 40, 45cm planting spaces, the cultivars (TERESA) were used in the experiment, with four replication for each treatment. The obtained results were analyzed averages were compared by Duncan Multipliers and the least significant difference(LSD) at the possibility>0.05 level. The evaluated characteristics in this experiment were marketable fresh weight per plant, per square meter, plant height, number of leaves, plants infected with soft rot, roots length, outlet leaves, and number of heads. The highest fresh weight 511.3 gr plant, the highest number of leaves/plant 39.4l, root length 9.1 cm, leaf length 31.3 cm obtained with the wide spacing, but the highest yield 10671.4 gm/m2 and plant height were obtained with the smaller spacing 10.15 cm. Lettuce may present a yield decrease due to the occurrence of lettuce soft rot disease caused by Pectobacterium carotovorum subsp. carotovorum. This study was designed to determine the perfect sample size for evaluating disease occurrence in fields in the last spring months to collect and store heads. The soft rot infection percent was higher in low spacing 3% because the high densities of plants make contact with the plants and lowest or no infection in high spacing.