Influence of planting schemes and time of tubers on some photosynthetic parameters in potato plants
The paper presents studies on the influence of tubers' planting schemes and planting time on some photosynthetic parameters in different potato plant varieties. We found that depending on the planting scheme and planting time of different potato varieties, the growth dynamics of the leaf area and the accumulation of total dry biomass do not differ significantly. However, the maximum value of these indices in both varieties pertains to the flowering phase of plants. Then, with the wilting of the above-ground mass of potato plants, the leaf size and area and the total dry biomass sharply decrease. In addition to those mentioned above, the planting time and scheme of potato tubers have a noticeable effect on the leaf area of Amiri-600 and Sevindge varieties. According to the indicators, the Amiri-600 variety exceeds the Sevindge variety for the entire growing season. The minimum leaf area is observed in April and at the end of June, strictly in the phases of tillering budding and the biological maturity of tubers. The third variant differs in the size of the leaf area, where potato plants were planted in the 70 × 30 cm scheme (except for the flowering phase in the Amiri-600 variety, whereas the maximum leaf area for this variety is noted in the 70 × 25 cm scheme-37.5 thousand m2/ha). A similar situation is observed in the dynamics of accumulation of total dry biomass, but without exception, which is indicated in the case of leaf area. We found that the value and variability of the photosynthetic potential in the studied varieties significantly change depending on their characteristics and the planting time and schemes of potato tubers. The maximum value of the photosynthetic potential in both varieties (Amiri-600 and Sevindge) was observed in the 3rd variant (where the plants are placed in the 70 × 30 cm scheme). The minimum value was observed in the 4th variant (where the potato tubers were planted on February 14-15). We also found that the average value of net photosynthetic productivity in plant ontogenesis in all five variants was higher in the Amiri-600 variety (7.5-10.1 g/m2 per day) than in the Sevindge variety (6.3-8.5 g/m2 per day).