Selective Absorption of K over Na in Sugar Beet Cultivars and its Relationship with Yield and Quality in Two Contrasting Environments of Central Greece

Abstract

Selective absorption (SA) of K over Na (i.e. the preferential absorption of K over Na) has been proposed as a Na tolerance mechanism but genotypic variation for this trait has not been assessed with sugar beet in the field. Thus, the aim of this study was to explore the variation of SA in 14 sugar beet cultivars and to relate SA with yield and root quality in two sites of central Greece (Amfithea and Pyrgetos). Genotypic variation for SA was significant and the SA values were higher in Pyrgetos, the site with the lower soil K and Na concentrations. In Pyrgetos, a favourable environment for sugar beet growth, cultivars yielded more and root quality was better. In that site, a negative relationship between SA and yield (fresh root weight, sugar yield) was found indicating that strong Na exclusion from root is a disadvantage for high yielding. Negative SA–yield relationships were evident in Amfithea when five cultivars with very low SA values (<1.00) were excluded from the analysis. Combined all the cultivars, curvilinear functions were the best‐fitted curves for the SA–yield relationships. In Amfithea, where sugar beets had lower water content in root (WCR), a significant, positive correlation between SA and % sucrose content in fresh root weight was found. This finding was ascribed to the dilution of sucrose in roots due to the increased WCR as a result of the increased root Na concentration. In both sites, SA was positively related with root K concentration and negatively with Na concentration. The positive correlations between SA and root α‐amino N concentration indicated that sugar beet N nutrition could be affected by the genotypic ability to exclude Na from the root.

A Prominent Role for Leaf Calcium as a Yield and Quality Determinant in Upland Cotton (Gossypium hirsutum L.) Varieties Grown Under Irrigated Mediterranean Conditions

“…Exclusion of Na in favour of K was beneficial for SY up to a K/Na ratio value of 5.74. Yet, higher ratios negated this impact on yield in accordance with findings in the semi‐halophytic sugar beet (Tsialtas and Maslaris ). Given the ability of Ca 2+ to block Na + ‐permeable (non‐selective) NSCC channels (Demidchik and Tester ), higher leaf Ca 2+ may be also beneficial for retaining more Na + in leaves, to be used for osmotic purposes.…”

Root Yield and Quality of Sugarbeet Hybrids with Pollinators Selected for Sodium, Potassium, or Amino-nitrogen Concentration

“…However, in most cases, altering only one of the impurity components resulted in only small changes in the traits normally associated with the economic value of the crop, i.e., root yield, sucrose concentration, loss-to-molasses, and recoverable sucrose per ton. Environment (years in this study) also can have a large impact on the concentration of some variables and change relationships among the components, as was observed with the potassium:sodium ratio and its relationship with sucrose, amino-nitrogen, and dry matter concentration (Tsialtas and Maslaris, 2009). A four-year trial with the pollinator lines used in this study provides further evidence that environment influences associations among impurity components and their relationships to processing quality.…”

“…Carter (1986) observed that an increase in the sodium concentration, or a decrease in the potassium:sodium ratio, decreased dry matter concentration and reduced sucrose concentration. Tsialtas and Maslaris (2009) concluded that cultivars that limit potassium uptake while favoring sodium absorption had lower sucrose concentrations due to the dilution of sucrose caused by a decrease in dry matter concentration. The correlation between the ability of a cultivar to limit sodium in the root and amino-nitrogen concentration was positive.…”

Sugar beet response to different K, Na and Mg ratios in applied fertilizers

“…Those results might be explained by dilution of sucrose due to the increased water content in storage roots (Tsialtas and Maslaris 2009). The content of melassogenic substances such as K and Na in storage roots were significantly modified by interaction between K-Mg-Na ratios and locations (F 12,180 = 1.97; P < 0.05 and F 12,180 = 6.24; P < 0.001).…”