Genetic evaluation and characterization using cluster heat map to assess NaCl tolerance in tomato germplasm at the seedling stage

Abstract

Salinity is a serious problem that limits crop growth and yield. The present study used plotting to evaluate 25 tomato (Solanum lycopersicum L.) accessions for various morpho-physiological parameters at the seedling stage and identify significantly salt-tolerant tomato lines at three different salinity levels. The pot experiment had a completely randomized design with three replicates in a factorial arrangement under greenhouse conditions. Tomato plants were exposed to 0 (control), 8, and 12 dS m-1 as NaCl stress at the seedling stage. The morpho-physiological traits, such as root and shoot length, root/shoot ratio, number of leaves, fresh and dry shoot weight, fresh and dry root weight, leaf area, Na + and K + concentrations, K + /Na + ratio, and tolerance index, were recorded to examine salt tolerance. According to principal component analysis (PCA), there were six principal components (PCs) with Eigen values > 1 and 77.2% of total cumulative variability. The PC1 (24.3%) revealed the highest variability followed by PC2 (16.2%).

Uncover the salt tolerance potential of accessions based on photosynthetic attributes and interaction plot in tomato (Solanum lycopersicum)

“…Moreover, cluster heatmap was conducted to distinguish a group of accessions with similar behavioural patterns, which further verified the PCA findings (Rehman et al., 2019). There are multiple advantages of using cluster heatmap which includes, immediate analysis of numerous attributes targeting to enhance accession grading, accession grouping under different environmental conditions and reliable assessment of accession screening on the basis of various salinity levels (Fellahi et al., 2019; Zeng et al., 2002).…”

“…Cluster heatmap analysis represents structurally pairwise dissimilarities and screened the accessions or variables under available clustering methods (Rehman et al., 2019). The cluster heatmap was plotted among 25 accessions on the basis of eight photosynthetic pigments under three levels of salinity stress.…”

“…(2017) and Rehman et al. (2019). One study investigated that photosynthetic pigments such as chlorophyll a and chlorophyll b , β‐carotene and pheophytin contents (chlorophyll breakdown product with no magnesium group) were significantly decreased under high salinity stress conditions as compared to the control in damiana plants ( Turnera diffusa Willd.)…”

“…On the other hand, plant germplasm innate genetic mechanism must be sufficient to tackle against different environmental stresses and standard procedure utilization to detect positively responding accessions (Akinci et al., 2004; Raza et al., 2017). Previous studies revealed variations in salt tolerance in tomato (Raza et al., 2017; Rehman et al., 2019); while, impacts of NaCl constraint on tomato varieties were investigated and found that due to rise in salt concentration, there was a progressive decrease in the growth parameters (Ahmed et al., 2020; Akinci et al., 2004). The analyses of variance revealed significantly altered behaviour of accessions, salinity levels and even accession into salinity level interaction in almost all the traits investigated except root and shoot lengths, and number of leaves per plant ( p < .01) (Table 1) and represented polygenic behaviour involved in salt tolerance (Salam et al., 1999).…”

Early Growth Stage Characterization and the Biochemical Responses for Salinity Stress in Tomato

“…Hence, the use of principal component analysis (PCA) can illustrate the most significant plant attributes governing salt tolerance [ 28 ]. In PCA, a three-way interaction plot aided with clustering can provide efficient prediction of the responses of salinity stress tolerance of the cultivars relying on trait associations existing between morpho-physiological traits and Na + stress [ 29 , 30 ]. To select relatively stress tolerant genotypes, various strategies have been proposed.…”