Effects of paclobutrazol and prohexadione–calcium applications on lettuce (Lactuca sativa L.) seedlings quality and plant growth

In this study, it was examined the effects on seedling growth and quality of Pro-Ca (0, 50, 100, 150 ppm) and PBZ (0, 25, 50, 100 ppm) applied in different seasons (autumn and spring) time (seed, germination, true leaf and germination and true leaf) and dosage to control staining at lettuce seedlings. In addition, sprayed lettuce (uygulama yapılmış) was grown in a hydroponic system and it was determined how long the application lasted until the harvesting period. In the study, seed application was found to be less effective on the parameters examined compared to leaf application. On the lettuce seedlings, it was determined that the inhibitory effect of leaf application of both chemicals increased is directly proportional to its application time and doses. It was found that the inhibitory effect of PBZ on the growth parameters in the seedling stage was higher than that of the Pro-Ca treatments, and this effect removed in the Pro-Ca treatments during the harvest period but continued at high doses in the PBZ treatments. As a result, germination + true leaf application time is the time to apply both stoppers at the highest level, they are not recommended to be used both suppress the growth above desired level and continue the stopping effect especially in PBZ applications even during the harvesting period. It has been determined that applications in true leaf stage give better results on seedling quality than other application times. The application doses for Pro-Ca is recommended as 100 and 150 ppm for season and condition which development is fast and as 50 and 100 ppm for conditions which development is slow. 25 and 50 ppm doses for PBZ should be preferred in the season and condition which development is rapid and 25 ppm and lower doses should be preferred for conditions which development is slow.