# The Impact of Effective Microorganisms on Flesh Color and Chemical Composition of Raw Potato Tubers
## 4 Discussion  
Public concerns about the use of chemicals in the environment and their economic and social impact have prompted farmers, researchers, and consumers to look for alternative farming methods and systems. Sustainable, ecological and biodynamic farming systems are considered environmentally friendly technologies. According to many authors [2; 3; 4; 11; 25], these cultivation systems have a positive effect on the biological activity of soils and plant biodiversity, and the harvested crops may have higher energy, nutritional, sensory, and rheological value. [PERSON] et al. [22] in testing EmaPlus and EMFarma in different concentrations in the cultivation of _Ageratum houstonianum_ Mill., proved that spraying plants 3 times with the EMFarma products at a concentration of 2% significantly increased the number of flower baskets in the main canopy and the weight of the aboveground part of the _Ageratum houstonianum_. On the other hand, [PERSON] et al. [23] and [PERSON] et al. [24] suggest that probiotic microflora cannot optimize the soil if it does not contain biodegradable organic matter. The results obtained in this research proved that effective microorganisms (EM) can be an alternative in fighting potato blight and simultaneously improve the quality values of tubers intended for processing, as confirmed by the results of studies by other authors [8; 20; 21; 25]. Still, EM's role in increasing resistance to this pathogen is less known [44]. The triple use of fungicides used in standard cultivation practice contributed to a significant darkening of the color of the raw tuber flesh (L*) compared with combined cultivation practices using effective microorganisms. There are no data on this subject in the available literature. [PERSON] and [PERSON] [45], as well as [PERSON] et al. [46] proved that in the tissues of plants infected with potato blight spores, a blue fluorescent zone is created between healthy and diseased tissue, which constitutes a type of barrier between the two types of tissues [47]. Hence, the flesh of raw tubers became darker. We believe that further work is needed to prove that effective microorganisms are helpful in creating a barrier for _Phytoophthora infestans_ spores and in providing better conditions for tuber yield growth and quality. The conducted research proved that the genetic features of the studied cultivars had the greatest impact on the color parameters of raw tuber flesh. In contrast, the chemical composition of tubers was modified only in the third order, after cultivation practices and conditions in the research years, without considering their interaction with each other. It proves the high genetic stability of the tested cultivars. The medium-early cultivar 'Tajfun' accumulated significantly more dry matter, starch, and vitamin C, while the early \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Dependent Variables** & **Regression Equation** & **Significance Level** &
\begin{tabular}{c} **Coefficient of** \\ **Determination (\%)** \\ \end{tabular} \\ \hline y1 & Y1 = 89.134 \(-\) 10.36 \(\times\) 1 \(-\) 0.359x4 & 0.001 & 66.42 \\ y2 & Y2 = 2.798 \(-\) 0.339x1 & 0.035 & 31.07 \\ y3 & Y3 = 44.125 \(-\) 3.471x1 & 0.022 & 37.78 \\ \hline \hline \end{tabular} x\({}_{1}\)—DM, x\({}_{2}\)—starch, x\({}_{3}\)—total sugar; x4—reducing sugars; x5—saccharose; x6—vitamin C; y1—L*, y2—a*; y3—b.  
\end{table} 
Table 15: Relationships between raw tuber flesh color indices and their quality elements. cultivar 'Bellaroosa' accumulated more total sugars, reducing sugars, and sucrose. The tested cultivars also showed a differentiated response to cultivation practices, especially in the interaction of genetic properties with the meteorological conditions prevailing in the years of the study. It should be assumed that the tested cultivars use effective microorganisms in different ways, e.g., for protection against potato blight (_Plyotrophlora infestants_ Mont de Bary) and _Alternaria solani_ and _Alternaria alternata_, which significantly shorten the growing season of potato.