Genetic diversity of standard leaf nutrients in Coffea canephora genotypes during phenological phases

Abstract

Diagnosing foliar nutritional status is essential for fertilizer recommendations and for the identification of nutrient imbalances. This study aimed to verify genetic diversity and establish mean standards (leaf nutrient contents; LNCs) and relationships among leaf nutrients (LNC relationships; LNCRs) in seven conilon coffee genotypes during both pre-flowering and bean-filling stages. Twenty crops from several cities in the northern region of Espírito Santo State, Brazil, with crop yield either equal to or greater than 100 bags per hectare (during two harvests) were assessed. A total of 140 samples were collected during each evaluation period for quantification of leaf nutrient contents (N, P, K, Ca, Mg, S, Fe, Zn, Cu, Mn, and B). The Ward procedure, a hierarchical genetic clustering method, was used to quantify the genetic diversity among genotypes. To examine differences between the LNCs and LNCRs, F-and Scott-Knott tests were used. LNCs and LNCRs showed significant differences among the conilon coffee genotypes during the evaluation periods. Additionally, the 8V, 10V,and 12V genotypes exhibited the highest values for most of the nutrients, especially for N, P, and Cu. Therefore, the clustering method revealed genetic diversity among genotypes for standard leaf nutrient levels, implying that leaf diagnosis could be specific to each genotype and phenological stage.

Research Article Genetic diversity as tool to identify standard leaf nutrients in cassava genotypes

“…Considering both N and P, Scott-Knott test resulted in two groups, corroborating with clustering analysis of the genotypes by the UPGMA method, however, with difference in number of genotypes in each group (Table 2). Such discrepancy was also reported by Gomes et al (2016) who assessed the genetic diversity of standard leaf nutrients in Coffea canephora genotypes during phenological phases. The genotypes 1, 3, 4 and 8 showed the higher N content values while the genotypes 1, 3, 4, 6 and 12 showed the higher P content ones.…”

“…Regarding the NR, significant differences were only observed in P/Zn and K/Ca relationships, where the genotypes 2, 3, 4, 5, 10, 11 e 12 showed the highest NR values for P/Zn, while the genotypes 3 and 10 showed the highest NR values for K/Ca (Table 3). The NR have been confirmed be useful in demonstrating the plant nutritional status since such method takes into account the relationships among nutrients rather than considering themselves in isolation (Partelli et al, 2006(Partelli et al, , 2007Gomes et al, 2016). That said, our NR values can represent an adequate nutritional status of cassava genotypes, even though small differences were observed.…”

“…Plant nutritional diagnosis depends on reference values such as critical level and sufficiency range for the nutrients concentration, especially in the leaves (Partelli et al, 2006;Gomes et al, 2016). However, these reference values are usually established in calibration experiments under controlled environments (Bhargava and Chadha, 1988), so that obtained values are of limited use.…”

“…Therefore, the nutritional requirements can be different among cassava genotypes so that researches aiming at evaluating standard leaf nutrients are essential for establishing adequate nutrient supply for each genotype. Recent study done with coffee plants showed leaf nutrients diagnoses can be genotype-specific and depend on phenological stages (Gomes et al, 2016).…”

“…Considering other crops such as coffee, the leaf nutritional status can be interpreted using the "sufficiency range" method, which generates leaf nutrient contents that are used as a reference (Partelli et al, 2006), although it does not consider genetic diversity (Gomes et al, 2016). Regarding to this latter aspect, multivariate methods has been used as useful tool for quantifying genetic diversity (Carvalho et al, 2012, Guedes et al, 2013Rodrigues et al, 2016;Kurosawa et al, 2017).…”