Development of the Primary Root System After Pre-Sowing Electromagnetic Treatments of Cotton Seeds Stored Under Natural Ageing Conditions

This paper presents the results obtained from laboratory studies after pre-sowing electromagnetic treatments of cotton seeds of the variety „Chirpan 539“. The lengths and mass of the plant roots were studied. The seeds were divided into three groups and were stored under natural aging conditions. The first group of seeds was stored for 3 years, the second group for 2 years and the third group for 1 year until the date of the test. A three-step electromagnetic treatment of the seeds was applied with controlled variables voltage $\mathrm{U}, \mathrm{KV}$ and duration of exposure $\tau, \mathrm{s}$. The parameters of the pre-sowing electromagnetic treatments, which produced a stimulating effect on the sowing properties of old seeds, were established. In seeds stored for 1 year prior to the pre-sowing electromagnetic treatment, a positive effect on the length and mass of the roots was found. These increased to $117.6 \%$ /C and $119.9 \% / \mathrm{C}$, respectively. For a positive effect of the pre-sowing electromagnetic treatment of cotton seeds of the variety, „Chirpan 539“, treatment with values of the controlled variables as per variant 4 is proposed: $U_{1}=6 \mathrm{KV}$ and $\tau_{1}=5 \mathrm{~s}, \mathrm{U}_{2}=4.5 \mathrm{KV}$ and $\tau_{2}=15 \mathrm{~s}, \mathrm{U}_{3}=3 \mathrm{KV}$ и $\tau_{3}=25 \mathrm{~s}$.