The main goal of this study was to identify the unique gene pool of old and historically valuable Quercus robur L. and Tilia cordata L. to be able to characterise their genetic diversity in order to determine the polymorphism by expressed sequence tag-single sequence repeat (EST-SSR) markers and identify the most valuable specimens.
Morphological description, molecular genetic analysis, and statistical analysis were used in studies. The genetic distances between old-value trees of different Quercus L. and Tilia L. were determined based on EST-SSR markers and morphological characteristics.
Using polymerase chain reaction (PCR), alleles of the expected size were obtained. It was determined that four to eight alleles were obtained by seven SSR markers in the studied Q. robur L. samples. According to the calculated value of the locus polymorphism index (polymorphism information content [PIC]), the most polymorphic was the marker SSRQrZAG 65; the PIC was 0.84. The lowest value of PIC was observed in the marker SSRQrZAG 11; the PIC was 0.69. Intragenetic polymorphism was detected for all studied markers. Among the studied samples of linden, two to five alleles were identified. It was found that the highest value of PIC was obtained for the marker Ts920 – 0.72. The least polymorphic was the marker Ts927 (PIC was 0.28), which is not only due to the small number of alleles, but also their uneven distribution in the sample. Intragenetic polymorphism was detected in four of the six markers analysed for T. cordata L.
In this study, polymorphism was detected in all studied samples of Q. robur L. and T. cordata L., which allows to assess their genetic diversity based on the distribution of alleles.
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.