Core Ideas Diagnostics of mineral nutrition in field is poorly developed for potato group Andigenum. Critical dilution curves for N, P, and K were validated in potato group Andigenum. The critical dilution curve serve to identify macronutrient status and to predict yield of potato in the tropics. The critical dilution curves (CDC) for nitrogen (Nc), phosphorus (Pc), and potassium (Kc) obtained from total dry biomass (W) and leaf area index (LAI) were used as a diagnostic tool to determine nutrient status and to adjust fertilization rates in two cultivars of potato (Solanum tuberosum L.) group Andigenum. The research determined allometric ratios of Nc, Pc, and Kc (%) and nutrition index (NI) based on W and LAI in cultivars Diacol Capiro (Capiro) and Pastusa Suprema (Suprema). Additionally, optimal fertilization rate was evaluated to achieve maximum yields during two growth cycles in contrasting environments of the Andean zone of Colombia. The CDC was validated using W in Capiro: Nc = 6.23W −0.320; Pc = 0.523W −0.198; Kc = 9.02W −0.269 and in Suprema: Nc = 6.74 W −0.327; Pc = 0.536W −0.186; Kc = 6.58W −0.135 and presented higher robustness than the CDC obtained from LAI. Capiro presented a lower dilution coefficient b for Kc than Suprema. The NI ranged between 0.25 and 1.32 with better fit in Capiro and relative yields (RY) starting from 40% without fertilization; for Suprema, null to marginal response to fertilization was obtained, indicating a luxury uptake of N (NI 1–1.5) with RY starting from 70%. Except for this research, Nc, Pc, and Kc have not been validated for cultivars of group Andigenum. The CDC for this cultivated group could serve to identify deficiency, sufficiency, or excess of N, P, and K, and to predict final yield per cultivar under highland equatorial conditions.

No abstract

Water availability is one of the main limitations of potato yields due to the high sensitivity of this crop to water deficit. The objective of this study was to determine the effect of water deficit on some physiological and biochemical responses in yellow diploid potato plants (Solanum tuberosum L. Group Phureja) of the cultivars Criolla Colombia, Criolla Dorada and Criolla Ocarina. Plants at tuber initiation were subjected to two treatments: continuous irrigation and water deficit imposed by withholding water at tuber initiation for 17 d. The results showed that plants under water deficit increased chlorophyll concentration, malondialdehyde and proline content. However, these plants showed a decrease in stomatal conductance, leafarea, total dry mass and exhibited a higher root/shoot ratio in all potato cultivars. In addition, all the cultivars also showed a decrease in yield, which was associated with sensitivity to water stress. Although the high content of proline and high root/shoot ratio may be associated with tolerance to water deficit, this association was not observed in these cultivars, probably due to the high reduction of stomatal conductance, which limited the production of photoassimilates, plant growth, and,therefore, the yield.

The relationship between tuber growth and demand for NPK in andigena group of potato (Solanum tuberosum L. ssp. andigena) is poorly documented under conditions of the Andean region of Colombia. It is necessary to establish a specific nutrient management for high yields to changes in edaphic-environmental supply and improve the production of Capiro and Supreme cultivars. Twelve treatments were evaluated at different stages (75-100-125-150 days after planting) of tuber growth using a repeated measures design with three factors: two cultivars (Capiro, Suprema); three locations with contrasting soils (Subachoque, Facatativá, and Choconta) and two levels of fertilization, F0 (unfertilized) and F1 (fertilized) of incomplete nature by differential fertilization by soil type. A positive correlation between fresh weight, dry weight and extraction of N, P and K (kg ha-1) by the tubers, beside harvest extraction index (HEI) was determined. Under optimal conditions of fertilization significant differences (P<0.001) between factor interactions cultivar x phenology x location for accumulation of N and P were detected, where Suprema was less demanding in the HEI of N (1,92 kg t-1 harvest) and HEI of P (0.38 kg t-1 harvest) than Capiro and was better adapted to acid soils of low fertility, in contrast the HEI of K Between 5.28 and 5.34 kg t-1 harvest did not show differences between cultivars due to the genotypic characteristics in the accumulation of dry biomass and starch that make them suitable for industrial use, in addition it was verified that the nutritional extraction depends on the genetic potential determined by the interaction with the environmental and edaphic supply.

No abstract