Potato (Solanum tuberosum L.) is a key crop for global food security. Therefore, under actual climatic changes, it is important to search for genotypes with steady characteristics in contrasting weather conditions. The aim of the present study was to establish the relationship between the development of the biomass and the number, respectively the weight of the tubers in order to introduce into the breeding program new genotypes, future varieties, with increased adaptability to environmental factors. The paper presents the results of a field study conducted to NIRDPSB Braşov, Romania, between 2021-2022, to evaluate some agronomic traits in potato genotpyes. A total of 15 potato genotypes (1901/6, 1930/3, 1901/12, 1927/1, 1897/2, 1979/5, 1891/1, 1927/3, 1901/11, 1941/8, 1895/4, 19-1876/7, 1939/2, 21-1895/1, 21-1901/7) along with one commercial cultivar (Braşovia) were evaluated. The experiment was laid out in a randomized complete block design with three replications. Data was recorded on plant height, main stem number per plant, tuber number and weight per plant and total tuber yield. Significantly positive phenotypic correlations for the height and mass of the plants were observed to the both determinations in the both years (r=0.90175, r=0.889, r=0.54505, r=0.562). The number and the weight of tubers were in an evolutionary process during the two experimental years. Genotypes 21-1901/7 (45.55 t/ha in 2021 and 34.17 t/ha in 2022) and 1939/2 (47.93 t/ha in 2021, respectively, 30.70 t/ha in 2022) recorded significantly high productions and even in the extreme conditions of 2022 maintained their high production capacity. The present findings show the existence of proper genetic variability and divergence among traits, and the identified traits can be used in a potato improvement program.

Thirteen potato genotypes with different level of resistance to potato late blight (Phytophthora infestans) pathogen were characterized using non-invasive method to determinate the chlorophyll content and the late blight influence. Field experiment was conducted to NIRDPS Brasov, Romania between 2021-2022. During the vegetation were applied the usual maintenance works (hilling, herbicides), including three treatments for Colorado beetle unless late blight control with fungicides. With SPAD 502 Plus meter (Chlorophyll Meter) were carried out 3 determinations on the leaves of the middle level of 3 plants from each genotype taken into the study. For the evaluation of the results, analysis of variance and Pearson’s correlation analysis were used. In 2021, following the measurements, closely negative correlations were observed between SPAD values and genotypes (-0.058), respectively the date of the observations (-0.126), while in 2022, the correlation was negative between the values regarding the date of the observations (-0.065), but positive at genotypes level (0.030).

At the National Institute of Research and Development for Potato and Sugar Beet – Brasov, Romania field experiments were carried out in order to collect data on quantitative traits (plant height, number tubers, tuber size, tuber weight) and yield of some new potato genotypes. It was used a complet randomized block design with four replicates. The number of steams varied between 14.5 steams / hill on genotype 1947/2 and 5.5 steam / hill on genotypes 1979/5 and 1901/12. The lowest value of the median leaf length was recorded at clone 21-1901/7 (56 cm) and the highest at clone 1947/2 (181 cm). Brasovia variety (control) has a poorly developed root system (48 g), also the genotypes 1891/7, 21-1895/1, 21-1901/7. Instead, genotypes 1901/6, 1927/1, 1971/9, 1965/16 have a high weight of the root system. Most spectacular production was provided by the line 1979/5 (77.90 t/ha), followed by the lines 1901/7 (45.55 t/ha) and 1939/2 (47.93 t/ha). The lines 1895/4, 1876/7, 1971/9, 1927/1, 1968/2, 1897/2, 1968/1 and 1947/2 also recorded significantly high productions.

In the present study thirteen potato clones were evaluated for resistance against late blight caused by Phytophthora infestans. Field experiment was conducted to NIRDPS Brasov, Romania, under natural epiphytotic conditions. The first symptoms of potato late blight disease were observed at 58 days after planting on Sasa x Pamela and R7Sasa x Orchestra clones. Out of 13 genotype, the incidence showed 2 genotpyes (Sasa R3 x Oceania and Sasa R7 x Orchestra) as highly susceptible, 2 varieties as moderately susceptible (Agria x Rustic (Cl1) and Agria x Rustic (Cl2)), 1 genotype as susceptible (Sasa x Pamela), 5 genotpyes relatively resistant (Sasa R3 x Rustic (Cl2), Sasa (R3) x Rustic (Cl3), Sasa (R3) x Orchestra, Sasa (R8) x Orchestra) Sasa (R6) x Orchestra) and 3 genotpys resistant (Sasa (R3) x Rustic (Cl1), Sasa x Fribel, Sasa x Florice). The Area under the disease progress curve (AUDPC) value was less for R3Sasa x Rustic, Sasa x Fribel and Sasa x Florice compared to other clones, indicating their higher level of resistance.