Determination of the effects of different wavelength light sources on germination and growing of tomato seeds

In this study, our main goal is to shorten the germination period of tomato seeds and to increase the germination rate and development rapidly. For this purpose, a germination cabinet was made by us and the germination and growth processes of tomato seeds were examined using different wavelength light sources. In the study, LED light sources with different colors were used instead of traditional light sources in artificial lighting. In addition, under different light spectrums, the effects on seed germination and the quality of tomato seedlings were examined according to the characteristics of the light. In the measurements, plant root length, total plant height, stem diameter, root collar diameter, number of leaves, marketable plant weight, root weight, number of leaves, crown width, chlorophyll amount and color (L, a, b) analyses were made in different colors and wavelengths depending on time. Within the scope of the thesis study, seeds of 3 local varieties, Karacadağ, Lice and Ahlat tomato varieties, which are still widely grown in various settlements in the region, were used as plant material. For the experiments, a plant growth cabin with light colors (red, cold white, blue, warm white (day)) was built on the ceiling of the shelves in the cabin consisting of four different compartments, with a height of 150 cm, a width of 75 cm and a depth of 31 cm, covered with a rigid heat insulation board. Seed germination and growth trays (violas) consisting of 6 x 12 cells were used to provide the necessary conditions for the growth of the seeds. The seeds were planted at a depth of approximately 1-1.5 cm. The tomato seeds were soaked 2 days before planting in the vials and left in a dark environment. After 2 days, 3 seeds were deposited into the soil filled in the vials to ensure initial germination. After planting, the vials placed in the growth environment were not exposed to light for 4 days. They were kept wet in a dark environment for 4 days and waited for emergence and sprouting. After the seeds emerged, they were moved to a light environment and an automatic timer was activated. With this, the durations of exposure to light and staying in the dark were also monitored. The plant was left in a closed growth environment with an automatic timer for 16 hours of light and 8 hours without light, average temperature 25 ºC and average humidity 57 rh. After the seeds were planted, plant growth characteristics were examined at 7-day intervals for 42 days. In the measurements, plant root length, total plant height, stem diameter, root collar diameter, number of leaves, marketable plant weight, root weight, number of leaves, crown width, chlorophyll amount, color (L, a, b) analyses were performed in different colors and wavelengths depending on time. The experiments were planned according to the randomized plot design and analyzed using the variance analysis method (ANOVA). Comparisons were made according to the DUNCAN test 5% and 1% significance level. According to the research results, the effect of time, variety and light type on the growing of plant length was found to be statistically very significant (p<0.001). In addition, the difference between the values of measurement time, variety and LED light colors used as light sources was found to be very significant (p<0.001). There was a significant increase in seedling lengths over time in all varieties and LED light colors. While the lowest seedling length for all varieties was obtained in the method using red light, the largest length was obtained in daylight. For example, while the plant height was measured as 8 cm in the Karacadağ tomato variety on the last measurement (6th Measurement), this value increased by more than 2 times in the same period and was measured as 17.50 cm in daylight. This situation shows that the effect of light color on the development of plant height is very important. While the lowest root length was obtained in red LED light for all varieties, the best development and length was obtained in daylight. The best values in terms of root length were measured in Karcadağ and Lice varieties, similar values. A decrease in SPAD values occurred in all varieties over time. The difference between them was found to be significant (p<0.001).