The study focuses on the polymorphism in soybean (Glycine max (L.) Merr.) cultivars based on molecular and morphological marker traits. The evaluation of soybean cultivars by DNA markers was carried out with the aid of polymerase chain reaction (PCR) analysis using four microsatellite markers (Satt 228, Satt 726, Satt 063 and Satt 114) and 20 morphological traits. The frequency of identified alleles varied from 0.02 to 0.28; polymorphism index by the markers under study averaged 0.89. Genetic distances between the cultivars by simple sequence repeat (SSR) markers and morphological markers were determined using cluster analysis. According to the obtained distribution by microsatellite markers, the largest distance (3.87) was between cultivars 'Alaska' and 'Alinda'. The most related were cultivars forming the same cluster with the value of 2.00, namely DH 530 and 'Abelina', 'OAC Leikviu' and 'Monarkh', 'SG SR Picor' and 'Hieba'. Cluster analysis of soybean cultivars by morphological traits showed that 'Abelina' was the most distant from the group of investigated cultivars with a value of genetic distances ranged from 2.8 to 11.0. Cultivars 'Amadeus' and DH 530, which formed a cluster and were at a distance of 1.4, appeared the most morphologically similar. Analysis of genetic distances by SSR markers and morphological traits showed a positive correlation by Mantel test. Description of morphological traits and microsatellite markers is useful for the identification of soybean cultivars, building-up collections of well-known cultivars and determination of the differences between them.

The purpose of study was to assess the genetic diversity of potato varieties of different maturity groups by SSR markers. Twenty-four potato varieties of different maturity groups (very early, yearly, medium, late) were investigated by 8 SSR markers (STM0019, STM3009, STM2005, STM2028, STM3012, STM3023, STM5136, STM5148) for genetic diversity assessment. To assess the genetic diversity of studied varieties, the cluster analysis was performed and the genetic distances between varieties were determined. As results of PCR analysis from 6 to 10 alleles were determined with an average of 7.88 alleles. The most polymorphic marker was STM2028 with PIC 0.89. The lowest value of PIC (0.78) was obtained for STM3012 marker. For other studied markers values of PIC were from 0.82 to 0.88. It was found, that the most similar varieties are varieties with genetic distance 3.74: Pravda and Riviera, Pravda and Vzirets. The most different varieties turned out to be Vzirets and Lilly, ESMEE and Opilla varieties with genetic distance 6.00. Thus, it was found that the major of studied varieties formed cluster grouts according their maturity groups.

An advanced approach to the assessment of varieties for the determination of their differences both within the DUS test and breeding is a combination of morphological traits and DNA markers. An implementation of this approach includes a correlation assessment between genetic distances matrices. To this end, the Mantel test is applied. The purpose of the study was to identify the main advantages and disadvantages of different software products for the Mantel test based on correlation investigation between DNA markers and morphological traits of lettuce varieties and maize lines. As a result of correlation calculation between 8 SSR markers and 36 morphological traits of 100 maize lines by XLSTAT (software for Microsoft Excel) p-value (probability of obtaining test results) was 0.0005. The value of this indicator obtained by PASSaGE software was 0.034. There was a pvalue of 0.045, which was calculated by GenAlEx 6.5 in Microsoft Excel (MS Excel). A similar result (0.036) was obtained by software environment R. The pvalues, which were calculated between 7 EST-SSR markers and 32 morphological traits for four lettuce varieties by XLSTAT, PASSaGE, GenAlEx, and R, were 0.033, 0.039, 0.038, and 0.035, respectively. In the study, the upper-tailed test served an alternative hypothesis type, the level of significance α was 0.05, the type of correlation was Pearson correlation, and the Monte Carlo method was used for p-value computation. Thus, the obtained p-values allow to reject the null hypothesis (H0) and adopt the alternative hypothesis Ha of correlation (p α). The correlation coefficient for maize lines was 0.05 and for lettuce varieties 0.65. Therefore, XLSTAT and software environment R are the most suitable instruments for correlation assessment between genetic distances.

The main factor which causes to decrease maize grain yield is drought. In most regions where maize is grown, the water stress during the growing period is caused by both lack of soil moisture and high air temperature. The purposes of our study were the estimation and selection of maize lines for drought and heat tolerance based on DNA markers and determination of the correlation between CAPS markers and plant ability to resist the water stress. As the result of study, the significant differences were found between leaf temperature of maize lines which contained favorable alleles by both CAPS markers in 2018 and 2019 (35.72 and 34.41ºC respectively), LSD0.05=1.27. The leaf temperature of maize lines which had SNP (A) by dhn С397 (36.95ºC) differenced significantly with lines contained favorable allele by rspC1090 or lines with no favorable alleles in 2018 (33.68 and 34.35ºC respectively). Based on analysis by seeds germinating in sucrose solution the significant differences were observed between the amount of sprouted seeds in lines contained SNP(G) by rspC1090 and lines without any favorable allele (4% and 2.25% respectively), LSD0.05= 1.70. As the result of correlation analysis, the positive correlation was determined between SNP(A) by dhnС397 marker in maize lines and leaf temperature in 2018-2019 (r=0.16). The positive correlation was observed between SNP(G)byrspC1090 and the percent of sprouted seeds in sucrose solution (r=0.31). Thus, for complex estimation and maize line selection for drought and heat tolerance it could be recommended to use two CAPS markers dhnC397 and rspC1090.

The carotene is a very important nutrient that provides the activity of molecular and biochemical processes in cells. Therefore, the estimation of genetic determinants involved in the management of the carotene synthesis is necessary for the selection of maize. DNA markers allow to select lines with high carotenoids content in grain for breeding purposes. 110 maize lines with a high content of carotenoids in grain using DNA markers lcyε-5'TE, lcyε-SNP216, lcyε-3'INDL and crtRB1-3'TE were studied. The dynamic and carotenoid content in simple hybrids and lines were determined by the absorption spectrum of β-carotene. Carotenoid content in grain of the lines under study ranged from 0.7 to 7.15 μg/mg. The highest values of the average content of carotene were obtained in the maize lines containing favourable alleles for the marker combinations lcyɛ-SNP216+lcyɛ-3'INDL and lcyɛ-SNP216+crtRB1-3'TE. For the marker lcyε-5'TE, no favourable allele was found among the studied genotypes. With the aid of spectrometry, the dynamics of carotenoid accumulation as a function of the grain development stage. Among the lines under study, the highest carotenoid content was recorded on the 15th and 23rd days after pollination (DAP). For the genotypes involved in the study, the total content of carotenoids in hybrids was higher than in their parent components. Therefore, DNA markers lcyε-SNP216, lcyε-3'INDL and crtRB1-3'TE are informative for assessing the maize genotypes for high carotenoid content in grain.