Evaluation of SPAD Index for Estimating Nitrogen and Magnesium Contents in Three Blueberry Varieties (Vaccinium corymbosum L.) on the Andean Tropics

Abstract

In the Ericaceae family, blueberries are the most commercially important species. Estimating the nutritional and physiological status of plants is a common practice carried out by producers. However, conventional methods are destructive, costly and time consuming. In recent years, methodologies such as measurements with the SPAD chlorophyll index have become available, which has proven to be an easy, fast and non-destructive method for estimating chlorophyll, N and Mg contents in the field. Therefore, this research aimed to estimate variations in SPAD readings between varieties and to determine whether Chlorophyll Index (SPAD) values are associated with Nitrogen and Magnesium contents in blueberry plants (Vaccinium corymbosum L.) from the varieties ‘Biloxi’, ‘Legacy’ and ‘Victoria’ in the vegetative phase under the conditions in the municipality of Paipa-Boyacá (Colombia). The varieties presented statistical differences in the SPAD index values, with a linear correlation between the SPAD index and the contents of N and Mg with a coefficient of determination (R2) greater than 0.8 in the three varieties. This result confirmed the usefulness and importance of using SPAD as a nutrition management tool in the evaluated varieties based on the SPAD readings, with a subsequent relationship with the threshold values of the foliar N and Magnesium status under field conditions.

Protein Hydrolysates from Crambe abyssinica Seed Cake as Potential Biostimulants for Root Development

“…The three hydrolysates determined, even if with different percentages, root shortening and increased branching, thus modifying the root architecture system and consequently stimulating nitrogen uptake in the roots and shoots, too. Furthermore, treatments increased the SPAD index in leaves, which is correlated with the nitrogen and chlorophyll content and thus plant photosynthesis [69]. Previously, Ertani et al [41,70,71] showed the effect of protein hydrolysates of vegetal or animal origin and phenol-containing organic substances on nitrogen and carbon metabolisms and nutrient uptake in maize hydroponic culture, suggesting a possible role of endogenous IAA, phenols, amino acids, and small peptides.…”

Can SPAD Values and CIE L*a*b* Scales Predict Chlorophyll and Carotenoid Concentrations in Leaves and Diagnose the Growth Potential of Trees? An Empirical Study of Four Tree Species

“…However, there are relatively few reports on tree species. An investigation of Vaccinium corymbosum confirmed the rationality and importance of using SPAD as a nutrition management tool [36]. Based on chlorophyll and SPAD measurements, Fe sufficiency threshold values were established in these two clones of hybrid poplar [73].…”

“…A considerable amount of SPAD measurement data has been reported for cereals (e.g., Hordeum vulgare var. coeleste, 26.30-55.95 [43]), vegetables (e.g., Spinacia oleracea, 23.48-39.08 [27]; Solanum tuberosum, 26.45-41.66 [37]), and horticultural crops (e.g., Vitis vinifera, 22.6-34.3 [20]; Vaccinium corymbosum, 57.4-73.1 [36]). Compared to herbaceous crops, the SPAD value of tree species seems to be much higher.…”

“…Most of the SPAD-related research focused on cereals [31][32][33][34][35], fruit crops [20,36], and vegetables [37], with some investigations on forest trees [38][39][40][41][42]. In addition, compared to the determination of SPAD values, the determination of CIE L*a*b* values in plant leaves has received little attention [20,27,43].…”