Salt Tolerant Gossypium hirsutum L. Cultivars are Mostly Long-Staple Length Cultivars

Background: Cotton is a major cash crop in the global and, in particular, the Indian markets, playing an important economic role in the textile and oil industries. The cotton plant is one of the highly bred plants that is highly sensitive to salt stress. As cotton is a non-food crop, the availability of non-saline terrain and water for the cultivation of cotton plants is only next to other food crops, thereby posing a need to better understand the salt tolerance of this plant. Gossypium hirsutum L. cultivars MCU 5, LRA 5166, and SVPR 2 were selected based on exomorphic traits like staple length and cropping season so that the genotypic responses to salt stress and salt shock can be compared for interpreting the effects of salinity on in vitro germination. Thus, this study aims to establish genotypic dependence on salinity tolerance. Results: The results affirmed genotypic variation in salinity tolerance, with MCU 5 tolerating salt stress better than LRA 5166 and SVPR 2 in all the observed stages of growth of the plant and the parameters measured. Further salt-tolerant cotton varieties were observed to be long-staple length varieties; staple length is the fiber character of the cotton lint. Moreover, salt tolerance in the vegetative growth stage of cotton plants is not independent of the germination stage of the plant.Conclusion: Nevertheless, the correlation of genotypic dependence to morphological characteristics, in particular, staple length (and cropping season), is of agronomic and commercial significance. Further research by screening and investigating a greater number of cultivars using biochemical and molecular techniques will provide a better understanding of this observed phenotypical relationship to the genotypes of cotton cultivars under salt stress.

Vermicompost humates as a salinity mitigator in the germination of basil

ABSTRACT: This study determined the effect of vermicompost humates as salinity mitigator in germination and morphometric characteristics of basil varieties seedlings, tolerant and sensitive to salinity, subjected to vermicompost humates diluted 1/60 (v/v) and 0, 50 and 100 mM NaCl in a completely randomized design with four replications. The rate and percentage of germination, root length, shoot height, root and shoot fresh and dry-weight were measured. The varieties showed differential response, highlighting Napoletano as the most tolerant. Vermicompost humates showed biostimulant effects on variables evaluated, allowing that tolerant variety to improve germination and growth, and increasing the salinity tolerance of the sensitive variety.

Identification of Cotton F1 Hybrids and their Parents through Molecular Marker under Salinity Stress

An experiment was carried out at Main Cotton Research Station, NAU, Surat, Gujarat, India during 2018–2020 to identify F1 hybrids and their parents through SSR marker for salinity tolerance in cotton. The four cotton parents (two salt tolerant and two salt sensitive) were crossed in a diallel fashion to obtain twelve cotton hybrids and subjected to DNA isolation and PCR amplification with SSR markers. In the present study, six SSR markers (TMB0409, DPL0094, BNL686, JESPR153, CM45 and MGHES006) were identified to be polymorphic between parents and the hybrids. The SSR primer TMB0409, DPL0094, JESPR153 and CM45 identified two fragments each from different parents in two, two, four and eight cotton hybrids, respectively, which confirmed true hybrids. Hence, the SSR molecular marker, individually or in combination can be used to distinguish and confirm the hybrid and parents in cotton with special reference to salinity. The PCA analysis revealed that BNL686–1 (248 bp) allele contributed significantly to the quantum of variation as explained by PC1. Hence, this allele is able to serve as a benchmark for ascertaining the efficient pattern of grouping between genotypes. Further, the marker CM45 amplified a fragment specific to the saline tolerant parents which was absent in sensitive parents as well as a fragment produced in sensitive parent which was absent in the tolerant parents, hence the molecular marker CM45 may associate with the salinity tolerance in cotton and can be used for salinity tolerant breeding program after confirming in a large population.

Seed Halopriming Improves Salinity Tolerance of Some Rice Cultivars During Seedling Stage

Background Saline land in coastal areas has great potential for crop cultivation. Improving salt tolerance in rice is a key to expanding the available area for its growth and thus improving global food security. Seed priming with salt (halopriming) can enhance plant growth and decrease saline intolerance under salt stress conditions during the subsequent seedling stage. However, there is little known about rice defense mechanisms against salinity at seedling stages after seed halopriming treatment. This study focused on the effect of seed halopriming treatment on salinity tolerance in susceptible cultivars, IR 64, resistant cultivars, Pokkali, and two pigmented rice cultivars, Merah Kalimantan Selatan (Merah Kalsel) and Cempo Ireng Pendek (CI Pendek). We grew these cultivars in hydroponic culture, with and without halopriming at the seed stage, under either non-salt or salt stress conditions during the seedling stage. Results The SES scoring assessment showed that the level of salinity tolerance in susceptible cultivar, IR 64, and moderate cultivar, Merah Kalsel, improved after seed halopriming treatment. Furthermore improved the growth performance of IR 64 and Merah Kalsel rice seedlings. Quantitative PCR revealed that seed halopriming induced expression of the OsNHX1 and OsHKT1 genes in susceptible rice cultivar, IR 64 and Merah Kalsel thereby increasing the level of resistance to salinity. The level expression of OsSOS1 and OsHKT1 genes in resistant cultivar, Pokkali, also increased but not affected on the level of salinity tolerance. On the contrary, seed halopriming decreased the level expression of OsSOS1 genes in pigmented rice cultivar, CI Pendek, but not affected on the level of salinity tolerance. The transporter gene expression induction significantly improved salinity tolerance in salinity-susceptible rice, IR 64, and moderate tolerant rice cultivar, Merah Kalsel. Induction of expression of the OsSOS1 gene in susceptible rice, IR 64, after halopriming seed treatment leads to balance the osmotic pressure by ion exclusion mechanisms, so that be tolerant to salinity stress. Conclusion These results suggest that seed halopriming can improves salinity tolerance of salinity-susceptible and moderate tolerant rice cultivars.

Evolution of Salt Tolerance in Arabidopsis Thaliana on Siliceous Soils Does Not Convey Tolerance to Saline Calcareous Soils

Purpose Alkaline salinity constrains crop yield. Previously, we found local adaptation of Arabidopsis thaliana demes to saline-siliceous soils (pH≤7) and to non-saline carbonate soils. However, any natural population of A. thaliana was localized on saline-alkaline soils. This suggests that salinity tolerance evolved on saline-siliceous soils may not confer tolerance to alkaline salinity. This hypothesis was explored by addressing physiological and molecular responses to saline-alkaline conditions of A. thaliana demes differing in salinity and carbonate tolerance.Methods A. thaliana native to saline-siliceous soils (G3), to non-saline carbonate soils (G1), or to soils with intermediate levels of these factors (G2) were cultivated in common gardens on saline-siliceous or saline-calcareous substrate. Hydroponics and irrigation experiments confirmed the phenotypes. Growth, mineral concentrations, genome differences, and expression of candidate genes were assessed in the different groups.Results G3 performed best on saline-siliceous soil and in hydroponics with salinity (pH 5.9). However, G3 was more sensitive to saline-alkaline conditions than G1 and G2. Fitness under saline-alkaline conditions was G2 > G1>G3 and G2 best maintained ion homeostasis under alkaline salinity. Whole genome scan did not differentiate among the groups, while distinctive patterns for FRO2, NINJA, and CCB4 were found and confirmed by qPCR.Conclusion In A. thaliana, salinity tolerance evolved on saline-siliceous soils does not provide tolerance to alkaline salinity. Plants from soils with intermediate conditions (G2) have more plasticity to adapt to alkaline salinity than those locally adapted to these individual stress factors. Higher expression of NINJA and CCB4 may contribute to this better adaptation.

Seed priming with Salicylic Acid (SA) and Hydrogen Peroxide (H2O2) Improve Germination and Seedling Growth of Wheat (Triticum aestivum) under Salt Stress

Aim: Salinity is a major barrier to successful crop production. Seed priming and exogenous application of different signaling molecules can efficiently confer salinity tolerance. Wheat is a major cereal crop in the world and salinity drastically reduces the wheat seedling growth and yield. Therefore, the present study was conducted to explore the potentiality of different signaling molecules such as salicylic acid (SA) and H2O2 to alleviate the salinity-induced growth inhibition of wheat. Place and Duration of the Study: The study was conducted in the Department of Seed Science and Technology, Bangladesh Agricultural University, from September-October, 2021. Methodology: The wheat (cv. BARI-Gom 24) seeds were soaked in normal tap water (hydro-priming), 1 mM SA, 2 mM SA, 0.1 mM H2O2, and 0.15 mM H2O2 solutions for 30 minutes. The untreated seeds were used as control. Eventually, primed seeds were exposed to 150 mM NaCl in Petri dishes during germination. Primed and non-primed seedlings were grown for 15 days under 150 mM NaCl stress condition. Results: The result revealed that salt stress significantly reduced germination percentage (GP), germination index (GI), seed vigor index (SVI), shoot and root length. The results also exhibited that photosynthetic pigments, total chlorophyll, carotenoids, lycopene, and beta-carotene contents were significantly reduced by salt stress. Seed priming with SA and H2O2 and hydro-priming promoted the germination percentage, seedling growth (including shoot and root length), SVI, and photosynthetic pigments. Conclusion: Pretreatment with 1 mM SA and 0.1 mM H2O2 was observed to be relatively more efficient in conferring salinity tolerance of wheat compared with other treating conditions. Overall, this study suggests that wheat seed priming with SA and H2O2 and hydro-priming can improve salinity tolerance. Aim: Salinity is a major barrier to successful crop production. Seed priming and exogenous application of different signaling molecules can efficiently confer salinity tolerance. Wheat is a major cereal crop in the world and salinity drastically reduces the wheat seedling growth and yield. Therefore, the present study was conducted to explore the potentiality of different signaling molecules such as salicylic acid (SA) and H2O2 to alleviate the salinity-induced growth inhibition of wheat. Place and Duration of the Study: The study was conducted in the Department of Seed Science and Technology, Bangladesh Agricultural University, from September-October, 2021. Methodology: The wheat (cv. BARI-Gom 24) seeds were soaked in normal tap water (hydro-priming), 1 mM SA, 2 mM SA, 0.1 mM H2O2, and 0.15 mM H2O2 solutions for 30 minutes. The untreated seeds were used as control. Eventually, primed seeds were exposed to 150 mM NaCl in Petri dishes during germination. Primed and non-primed seedlings were grown for 15 days under 150 mM NaCl stress condition. Results: The result revealed that salt stress significantly reduced germination percentage (GP), germination index (GI), seed vigor index (SVI), shoot and root length. The results also exhibited that photosynthetic pigments, total chlorophyll, carotenoids, lycopene, and beta-carotene contents were significantly reduced by salt stress. Seed priming with SA and H2O2 and hydro-priming promoted the germination percentage, seedling growth (including shoot and root length), SVI, and photosynthetic pigments. Conclusion: Pretreatment with 1 mM SA and 0.1 mM H2O2 was observed to be relatively more efficient in conferring salinity tolerance of wheat compared with other treating conditions. Overall, this study suggests that wheat seed priming with SA and H2O2 and hydro-priming can improve salinity tolerance.

Identification of a Saltol-independent Salinity Tolerance Polymorphism in Rice Mekong Delta Landraces and Characterization of a Promising Line, Doc Phung

The Mekong Delta River in Vietnam is facing salinity intrusion caused by climate change and sea-level rise that is severely affecting rice cultivation. Here, we evaluated salinity responses of 97 rice accessions (79 landraces and 18 improved accessions) from the Mekong Delta population by adding 100 mM NaCl to the nutrient solution for up to 20 days. We observed a wide distribution in salinity tolerance/sensitivity, with two major peaks across the 97 accessions when using the standard evaluation system (SES) developed by the International Rice Research Institute. SES scores revealed strong negative correlations (ranging from –0.68 to –0.83) with other phenotypic indices, such as shoot elongation length, root elongation length, shoot dry weight, and root dry weight. Mineral concentrations of Na+ in roots, stems, and leaves and Ca2+ in roots and stems were positively correlated with SES scores, suggesting that tolerant accessions lower their cation exchange capacity (CEC) in the root cell wall. The salinity tolerance of Mekong Delta accessions was independent from the previously described salinity tolerance–related locus Saltol, which encodes an HKT1-type transporter in the salinity-tolerant cultivars Nona Bokra and Pokkali. Indeed, genome-wide association studies (GWASs) using SES scores and shoot dry weight ratios of the 79 accessions as traits identified a single common peak located on chromosome 1. This SNP did not form a linkage group with other nearby SNPs and mapped to the 3′ untranslated region of gene LOC_Os01g32830, over 6.5 Mb away from the Saltol locus. LOC_Os01g32830 encodes chloroplast glycolate/glycerate translocator 1 (OsPLGG1), which is responsible for photorespiration and growth. SES and shoot dry weight ratios differed significantly between the two possible haplotypes at the causal SNP. Through these analyses, we characterize Doc Phung, one of the most salt-tolerant varieties in the Mekong Delta population and a promising new genetic resource.