Growth, yield and fruit quality of Mexican tomato landraces in response to salt stress

Abstract

The Mexican tomato landraces ‘Campeche’, ‘Oaxaca’, ‘Puebla’, and ‘Veracruz’, and the commercial hybrid ‘Vengador’ were evaluated in response to four levels of NaCl (0, 30, 60 and 90 mM) applied through the nutrient solution in a hydroponic system under greenhouse conditions. Yield and dry biomass weight of roots, stems and leaves were reduced by increasing salinity stress, while fruit quality characteristics were improved, with the magnitude of the changes being genotype-dependent. The landrace ‘Veracruz’ produced the lowest yield, 1.06 t ha-1 under control conditions and 0.59 t ha-1 when treated with 90 mM NaCl, amounting to a 44% reduction that was, however, the lowest yield decrease among all genotypes tested. Paradoxically, ‘Veracruz’ was the only landrace displaying a reduction in the root/shoot ratio when exposed to high salinity, indicating more sensitivity to salinity as compared to the other landraces and the hybrid tested. ‘Campeche’ performed the poorest in response to salinity with the most pronounced yield reductions, recording 71.1%, 80.1% and 89.6% yield decreases when comparing plants exposed to 30, 60 and 90 mM to the control, respectively. Although at each salinity level the ‘Veracruz’ fruits showed the highest °Brix value as compared to the other landraces and the hybrid, ‘Oaxaca’ and ‘Puebla’ fruits had a greater increase in °Brix between the control and 90 mM NaCl (109.2% and 110.4%, respectively). With 90 mM NaCl, ‘Oaxaca’ fruits also registered the highest decrease in pH (6.1%) and the highest increase in total soluble sugars (106.7%) with respect to the control.

Physico-Chemical, Nutritional, and Sensory Evaluation of Two New Commercial Tomato Hybrids and Their Parental Lines

“…The values for carbohydrates, based on glucose plus fructose levels in this experiment, demonstrate the strong influence of genotype and individual genetic heritage of cultivars on the potential to accumulate a certain amount of carbohydrates. Apart from crop and growth conditions and genotypes, the levels of glucose and fructose, other useful compounds in tomatoes can vary greatly depending on some stressors [40,45]. The stress factors can be represented by water, saline, thermal stress, etc.…”

Effect of Saline–Alkali Stress on Sugar Metabolism of Jujube Fruit

“…In a previous study, after sprayings with different concentrations of an NaCl solution, the fructose, glucose, and sucrose in grapefruit increased under low salinity (20~60 mM) and decreased under high salinity (100~150 mM) [6,7]. Differences in the sugar contents of fruits caused by different concentrations of salt stress have also been reported for tomatoes [4,8,9], Lycium chinensis [5], and figs [10]. These differences are often related to the activities of sucrose-metabolizing enzymes and gene expression levels [11].…”

“…Sugar is an important factor of fruit quality that is often affected by external environments such as light, water, salinity, and temperature [2]. Some natural phenomena in production and previous studies have shown that [3][4][5][6] mild salt stress can improve sugar accumulation in fruits and severe salt stress can decrease the sugar content. In a previous study, after sprayings with different concentrations of an NaCl solution, the fructose, glucose, and sucrose in grapefruit increased under low salinity (20~60 mM) and decreased under high salinity (100~150 mM) [6,7].…”

Evaluation of Tomato Germplasm for Salinity Tolerance at the Seedling Stage

“…In tomatoes at the pre-flowering stage, the salinity of 6 dS/m and 12 dS/m reduce the plant height, flower cluster, primary branches, fruit cluster, number of fruits, and fruit yield plant -1 , and in leaves, it reduces the content of the amino acid and increase the total and reducing sugars (Moniruzzaman et al, 2013;Rai et al, 2016). At salinity stress, the tomato plant reduces the dry biomass of roots, leaves, stems, and fruits (Ladewig et al, 2021). Salinity causes a considerable reduction in the yield of tomato crops.…”

“…Osmotic and ionic stresses caused by the salinity stress affect the tomato plant at the cellular level. The tomato plant is sensitive to salt stress, with yield reduction observed above EC of 2.5 dS m -1 (Siddiky et al, 2012;Ladewig et al, 2021). At the global level, salinity affects irrigated and dryland agriculture, estimating 19.5% and 2.1%, respectively.…”