不同硼效率油菜品种细胞壁组分中硼的分配

应用不同硼效率甘蓝型油菜品种(Brassica napus),研究硼在细胞壁各组分中的分配规律。结果表明,细胞壁硼主要结合在果胶中,根系细胞壁80%以上的硼、叶片细胞壁95%以上的硼结合在果胶中。叶片细胞壁果胶硼含量高于根系细胞壁。品种间细胞壁各组分硼含量存在差异,低效品种苗期叶片中螯合剂可溶性果胶硼含量显著高于高效品种     

Maize genotypes with deep root systems tolerate salt stress better than those with shallow root systems during early growth

Maize (Zea mays L.) is susceptible to salinity but shows genotypic variation for salt tolerance. How maize genotypes with contrasting root morphological traits respond to salt stress remains unclear. This study assessed genotypic variation in salinity tolerance of 20 maize genotypes with contrasting root systems exposed to NaCl for 10 days (0, 50 mM or 100 mM NaCl, added in four increments every other day from 14 days after transplanting, DAT) in a semi-hydroponic phenotyping system in a temperature-controlled greenhouse. Considerable variation was observed for each of the 12 measured shoot and root traits among the 20 genotypes under NaCl treatments. Salt stress significantly decreased biomass production by up to 54% in shoots and 37% in roots compared with the non-saline control. The 20 genotypes were classified as salt-tolerant (8 genotypes), moderately tolerant (5) and salt-sensitive (7) genotypes based on the mean shoot dry weight ratio (the ratio of shoot dry weight at 100 mM NaCl and non-saline control) ± one standard error. The more salt-tolerant genotypes (such as Jindan52) had less reductions in growth, and lower shoot Na⁺ contents and higher shoot K⁺/Na⁺ ratios under salt stress. The declared salt tolerance was positively correlated with shoot height, shoot dry weight and primary root depth, and negatively correlated with shoot Na⁺ content at 100 mM NaCl. Primary root depth is critical for identifying salt responsiveness in maize plants and could be suggested as a selection criterion for screening salt tolerance of maize during early growth. The selected salt-tolerant genotypes have potentials for cultivation in saline soils and for developing high-yielding salt-tolerant maize hybrids in future breeding programmes.     

Comparative studies on nanostructures of three kinds of pectins in two peach cultivars using atomic force microscopy

Firmness is an important postharvest quality property of fruit. To investigate the reasons for firmness differences between soft and crisp fruit cultivars, two peach (Prunus persica L. Batsch) cultivars (soft and crisp) were selected to compare the nanostructures of pectins. Water-soluble pectin (WSP), chelate-soluble pectin (CSP) and sodium carbonate-soluble pectin (SSP) were extracted and nanostructures were conducted and analyzed using atomic force microscopy (AFM). The results show that SSP chain lengths were different between the two cultivars with average SSP lengths of 249 nm and 57 nm for fruit of the crisp and soft cultivars, respectively, while the WSP and CSP chain lengths were not much different. There were no statistical differences for chain heights and widths in the three kinds of pectins between fruit of the two cultivars. All the chain heights were about 1–5 nm. The results indicate that neutral sugar-rich pectins from the primary cell wall of peach flesh might be the cause of the main differences in pectin nanostructures between the two cultivars. The neutral sugar-rich pectins in primary cell walls of peach might also be the reason for firmness differences.     

Paclobutrazol improves salt tolerance in quinoa: Beyond the stomatal and biochemical interventions

Quinoa is gaining importance on global scale due to its excellent nutritious profile and environmental stress‐enduring potential. Its production decreases under high salt stress but can be improved with paclobutrazol application. This study showed involvement of some potential protective mechanisms in root and leaf tissues of quinoa plants treated with paclobutrazol (PBZ) against high salinity. The treatment levels were based on preliminary experiments, and it was found that salt stress (400 mm NaCl) markedly reduced growth and photosynthetic pigments while PBZ (20 mg/L) application significantly improved these attributes. Stomata density and aperture declined on adaxial and abaxial surfaces of leaves due to salinity. Paclobutrazol application significantly improved the stomatal density on both surfaces of leaves. Concentration of proline and soluble sugars increased in root and leaf tissues under salinity, which was more obvious in PBZ‐treated plants. Salinity stress induced the oxidative damage by increasing lipid peroxidation (MDA) level in roots and more specifically in leaf tissues. However, PBZ treatments ameliorated the drastic effects of salinity and markedly reduced oxidative damage in salt‐stressed quinoa plants. Enhanced activity of enzymatic antioxidants such as superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD) was triggered by PBZ application, more pronounced in leaf than root tissues. Based on these findings, we conclude that PBZ application improves the salt tolerance in quinoa by activation of the above‐mentioned physiological and biochemical mechanisms specifically in leaves.     

Yield and Agronomic Traits of Norin 10-derived Spring Wheats Adapted to Northwestern Mexico

Activities of enzymes nitrate reductase (NR) and nitrite reductase (NiR) were determined in rice seedlings differing in salt tolerance raised under increasing levels of NaCl salinity. Salinity caused marked increase in in vivo NR activity in roots and shoots of salt tolerant cvs. CSR-1 and CSR-3 whereas in salt sensitive cvs. Ratna and Jaya a marked inhibition in in vivo NR activity was observed under salimzation. Under both controls as well as salt treatments in all cultivars roots always maintained higher level of in vivo NR activity than shoots. In vitro NR activity increased in both roots and shoots of all cultivars during early days of growth with maximum at 10–15 days and decreased thereafter. In salt tolerant cultivars salinity caused an increase in in vitro NR activity in shoots but not in roots whereas in salt sensitives activity of the enzyme was always more in salt stressed seedlings compared to controls. Salinity increased NiR activity in seedlings of sensitive cultivars whereas in tolerants suppression in root NiR activity was observed due to salinity. Like NR the activity of NiR was also higher in roots than shoots. 1 M NaCl in the enzyme assay medium suppressed in vivo NR activity in roots of 15 days old nonsalinized seedlings with more suppression in sensitive cultivars than tolerants. Results suggest possible different behaviours of nitrogen assimilatory enzymes in rice cultivars differing in salt tolerance and that salt tolerance ability is associated with high in vivo NR activity in seedlings and its further activation under salinization.     

Influence of NaCl Salinity on Growth and Metabolic Status of Protein and Amino Acids in Rice Seedlings

Seeds of four rice cultivars differing in salt tolerance when grown under increasing level of NaCl salinity and seedling vigour as well as metabolic status of total and soluble proteins, amino acids were evaluated in seedlings at increasing days of growth it was observed that increasing level of salinity caused loss in dry wt. of seedlings as well as reduction in lengths of root and shoot. In both sets of cultivars salt stressed seedlings showed higher levels of total as well as soluble proteins, total amino acids compared to non salinized seedlings. In roots of salt susceptible cvs. Ratna and Jaya increased salinity up to 14 mmhos/cm remarkably increased total as well as soluble protein level whereas in shoots moderate level of salinity increased protein level compared to controls and higher salinity level caused suppression in such increase. Tolerant cultivars always maintained higher levels of total as well as soluble proteins and total amino acids in salt stressed seedlings compared to susceptibles. Amino acids which accumulated greatly in salinized seedlings were arginine, phenylalanine, alanine, leucine, proline, valine and glutamine. Results suggest possible role of proteins and amino acids in confering salt tolerance in rice.     

How does water and salt stress affect the germination and initial growth of Brazilian soya bean cultivars?

The effects of water and salt stress on rate of germination and seedling growth were investigated under laboratory conditions in 46 soya bean genotypes from Central-West region of Brazil to verify how these stresses may limit crop establishment during the initial growth stage and also to identify the most tolerant genotypes to drought and salinity. Mild water and salt stresses were imposed by seed exposure to –0.20 MPa iso-osmotic solutions with polyethylene glycol—PEG 6000 (119.57 g/L) or NaCl (2.357 g/L) for 12 days at 25°C. The germination percentage, seedling length and seedling dry matter were measured, and then, salt or drought tolerance indexes were calculated. The “NS 5909 RG,” “NS 7000 IPRO,” “NS 7338IPRO,” “FPS Solimões RR,” “NS 5151 IPRO,” “SYN 13610 IPRO,” “LG 60177 IPRO,” “NS 6909 IPRO” and “BMX Desafio RR” were identified as the most drought-tolerant genotypes, whereas under salinity conditions, the genotypes “5D 615 RR,” “BMX Desafio RR,” “5D 6215 IPRO” and “BMX Ponta IPRO” were identified as tolerant. The “BMX Desafio RR” is the genotype most adapted to both stress conditions and, therefore, should be used under conditions of water shortage and excess salt in the soil at sowing time.     

Growth Properties and Ion Distribution in Different Tissues of Bread Wheat Genotypes (Triticum aestivum L.) Differing in Salt Tolerance

Four bread wheat genotypes differing in salt tolerance were selected to evaluate ion distribution and growth responses with increasing salinity. Salinity was applied when the leaf 4 was fully expanded. Sodium (Na⁺), potassium (K⁺) concentrations and K⁺/Na⁺ ratio in different tissues including root, leaf‐3 blade, flag leaf sheath and flag leaf blade at three salinity levels (0, 100 and 200 mm NaCl), and also the effects of salinity on growth rate, shoot biomass and grain yield were evaluated. Salt‐tolerant genotypes (Karchia‐65 and Roshan) showed higher growth rate, grain yield and shoot biomass than salt‐sensitive ones (Qods and Shiraz). Growth rate was reduced severely in the first period (1–10 days) after salt commencements. It seems after 20 days, the major effect of salinity on shoot biomass and grain yield was due to the osmotic effect of salt, not due to Na⁺‐specific effects within the plant. Grain yield loss in salt‐tolerant genotypes was due to the decline in grain size, but the grain yield loss in salt‐sensitive ones was due to decline in grain number. Salt‐tolerant genotypes sequestered higher amounts of Na⁺ concentration in root and flag leaf sheath and maintained lower Na⁺ concentration with higher K⁺/Na⁺ ratios in flag leaf blade. This ion partitioning may be contributing to the improved salt tolerance of genotypes.     

Genetic variation in root development responses to salt stresses of quinoa

Soil salinity has become a serious environmental abiotic stress limiting crop productivity and quality. The root system is the first organ sensing the changes in salinity. Root development under elevated salinity is therefore an important indicator for saline tolerance in plants. Previous studies focused on varietal differences in morphological traits of quinoa under saline stresses; however, variation in root development responses to salinity remains largely unknown. To understand the genetic variation in root development responses to salt stress of quinoa, we conducted a preliminary screening for salinity response at two salinity levels of a diverse set of 52 quinoa genotypes and microsatellite markers were used to link molecular variation to that in root development responses to salt stresses of represented genotypes. The frequency distribution of saline tolerance index showed continuous variation in the quinoa collection. Cluster analysis of salinity responses divided the 52 quinoa genotypes into six major groups. Based on these results, six genotypes representative of groups I to VI including Black quinoa, 2-Want, Atlas, Riobamba, NL-6 and Sayaña, respectively, were selected to evaluate root development under four saline stress levels: 0, 100, 200 and 300 mM NaCl. Contrasts in root development responses to saline stress levels were observed in the six genotypes. At 100 mM NaCl, significant differences were not observed in root length development (RLD) and root surface development (RSAD) of most genotypes except Black quinoa; a significant reduction was observed in this genotype as compared to controls. At 200 mM NaCl, significant reduction was detected in RLD and RSAD in all genotypes showing this as the best concentration to discriminate among genotypes. The strongest inhibition of root development was found for all genotypes at 300 mM NaCl as compared to lower saline levels. Among genotypes, Atlas of group III shows as a saline-tolerant genotype confirming previous reports. Variation in root responses to salinity stresses is also discussed in relation to climate conditions of origins of the genotypes and reveal interesting guidelines for further studies exploring the mechanisms behind this aspect of saline adaptation.     

Leaf Cell‐Wall Components as Influenced in the First Phase of Salt Stress in Three Maize (Zea mays L.) Hybrids Differing in Salt Resistance

The leaf cell wall (CW) chemical composition of three maize (Zea mays L.) hybrids (salt‐resistant SR 03 and SR 12, salt‐sensitive Pioneer 3906) was investigated in the first phase of salt stress (100 mm NaCl) compared with the control (1 mm NaCl) treatment to investigate whether changes in CW composition were responsible for shoot growth reduction. Salt treatment caused a strong inhibition in shoot growth with a concomitant increase in the ratio between CW dry mass (DM) and shoot fresh mass (FM) and a decrease in CW cellulose concentrations in all hybrids. NaCl caused a large increase in the concentrations of total and non‐methylated uronic acid (UA) in salt‐sensitive Pioneer 3906 and salt‐resistant SR 12. The onset of the accumulation of non‐methylated UA was delayed in SR 12, which indicates that this may be one reason for the better growth performance of this hybrid under salt stress compared with Pioneer 3906. It is concluded that a low accumulation of non‐methylated UA in leaf CW may, among other mechanisms, contribute to salt resistance in the first phase of salt stress.     

On the use of spectral reflectance indices to assess agro‐morphological traits of wheat plants grown under simulated saline field conditions

Successful breeding of plants for salinity stress tolerance requires realistic growing conditions and fast, non‐destructive evaluation techniques for phenotypic traits associated with salinity tolerance. In this study, we used subsurface water retention technique (SWRT) as a growing condition and spectral measurements as an evaluation method to assess different agro‐morphological traits of salt‐tolerant (Sakha 93) and salt‐sensitive (Sakha 61) wheat genotypes under three salinity levels (control, 60, and 120 mm NaCl). The effects of salinity on agro‐morphological traits were evaluated and related with forty‐five published vegetation‐ and water‐spectral reflectance indices (SRIs) taken at both the heading and grain milk growth stages for each salinity level, genotype, and growth stage. In general, the agro‐morphological traits gradually decreased as salinity levels increased; however, the reduction in these traits was more pronounced in Sakha 61 than in Sakha 93. The effect of salinity levels and their interaction with genotypes on the SRIs was only evident at the grain milk stage. The performance of the spectral reflectance indices depicted that the closest associations with agro‐morphological traits depended on salinity level, degree of salt tolerance of the genotypes, and growth stage. The SRI‐based vegetative indices correlated better with growth and yield of Sakha 93 than SRI‐based water indices and vice versa for Sakha 61. The SRI‐based vegetative and water indices are effective for assessment of agro‐morphological traits at early growth stages under high salinity level. The functional relationship between grain yield per hectare and the best SRIs was linear for the high salinity level and Sakha 61; however, the quadratic model was found to best fit this relationship for the control, moderate salinity level, and Sakha 93. The overall results indicate that the usefulness of the SRIs for assessment of traits associated with salinity tolerance is limited to salinity level and growth stage.     

Antioxidative Response of Quinoa Exposed to Iso‐Osmotic,Ionic and Non‐Ionic Salt Stress

Antioxidants play an important role in adapting plants to abiotic stress by detoxifying reactive oxygen species (ROS). Involvement of antioxidant enzymes in abiotic stress tolerance of highly stress‐tolerant quinoa was studied in a climatic chamber at 6 mOsm (milliosmolar) ionic (300 mm NaCl) and non‐ionic (600 mm mannitol) salts combined with increasing levels of potassium K1 and K2 (6, 12 mm ), respectively. Fifteen days of salt treatment (both ionic and non‐ionic) decreased plant growth (shoot and root fresh weight), stomatal conductance and chlorophyll content index. Furthermore, both forms of salt stress increased the activities of superoxide dismutase, catalase, ascorbate peroxidase and peroxidase up to 2.33‐, 3.98‐, 4.78‐ and 5.55‐folds, respectively, compared to no salt treatment, whereas membrane stability index decreased corresponding to increase in lipid peroxidation (malondialdehyde), with salt treatments compared to non‐stressed plants. However, no significant effect of potassium and salt treatments has been noticed on the maximal photochemical efficiency of PSII. The results suggested that enhanced antioxidant enzymes activity under salt stress could be one of the factors responsible for abiotic stress tolerance in quinoa.     

Genetic variation in salt tolerance at the seedling stage in an interspecific backcross inbred line population of cultivated tetraploid cotton

Soil salinity reduces cotton growth, yield, and fiber quality and has become a serious problem in the arid southwestern region of the Unites States. Development and planting of salt-tolerant cultivars could ameliorate the deleterious effects. The objective of this study was to assess the genetic variation of salt tolerance and identify salt tolerant genotypes in a backcross inbred line (BIL) population of 142 lines from a cross of Upland (Gossypium hirsutum) × Pima cotton (G. barbadense) at the seedling growth stage. As compared with the non-saline (control) conditions, seedlings under the salinity stress (200 mM NaCl) showed a significant reduction in all the plant growth characteristics measured, as expected. Even though the two parents did not differ in salt response as measured by percent reduction, significant genotype variations in the BIL population were detected for all traits except for leaf number. Based on percent reduction of the traits measured, several BILs were more salt tolerant than both parents. The results indicate that transgressive segregation occurred during the process of backcrossing and selfing even though both parents were not salt tolerant during seedling growth. Coefficients of correlation between all the traits were significantly positive, indicating an association between the traits measured. The estimates of broad-sense heritability were 0.69, 0.46, 0.47, 0.43, and 0.49 for plant height, fresh weight of shoot and root, and dry weight of shoot and root, respectively, indicating that salt tolerance during cotton seedling growth is moderately heritable and environmental variation plays an equally important role. The overall results demonstrate that backcrossing followed by repeated self-pollination is a successful strategy to enhance salt tolerance at the seedling stage by transferring genetic factors from Pima to Upland cotton.     

Productive behaviour of “cherry”-type tomato irrigated with saline water in relation to nitrogen fertilisation

Research on tomato tolerance to salt stress indicates that thresholds of ECe for the decrease of yield and plant growth are moderately high and differ among varieties. Some results suggest that nitrogen fertilisation may help increase the threshold for yield reduction. Most literature data have been collected either in small-scale containers or in the open field and both systems are often subjected to disturbances making hypotheses difficult to test. A set of experiments was conducted in large containers in a rainout-shelter field setting to assess the response of a “cherry”-type tomato variety to irrigation with saline water and to test the hypothesis that salt stress may be mitigated through nitrogen fertilisation.Tomato hybrid ‘TOMITO F 1’ was irrigated with water at four levels of salinity (0.7, 2.5, 5.0, and 10.0 dS m⁻¹ ECw) and three levels of nitrogen fertilisation (no added nitrogen = N0, 120 kg ha⁻¹ = N120, and 160 kg ha⁻¹ = N160) in factorial combination. Plant growth and water use were measured throughout the growth cycle, and gas exchange and leaf water potentials were measured at the fruit-growing stage. Two growing cycles were completed, one with high initial soil nitrogen (HN) and the second with low initial soil nitrogen (LN).No interaction was found between the application of nitrogen and plant response to saline irrigation. Plant growth and yield were affected by the saline treatments and less by nitrogen fertilisation, especially in the HN treatment.Irrigations with saline water resulted in increased values of soil salinity. Water use was lower with increasing soil and water EC, and the marginal reduction ranged from about 31 mm for each dS m⁻¹ of water EC at low salinity to about 6 mm for each dS m⁻¹ at high water EC.The marginal reduction in yield ranged from about 3.3 t ha⁻¹ for each dS m⁻¹ at low salinity water to less than 0.6 t ha⁻¹ for each dS m⁻¹ at high EC of irrigation water. Yield reductions were mainly due to lower fruit weight. Biomass values decreased as the salinity levels increased and fruit quality was improved in both cycles with increasing salinity.The hypothesis that nitrogen fertilisation could help tomato plants increase tolerance to salinity was not confirmed by data of this experiment and alterations induced by salinity in plant growth, yield and quality stabilised at high levels of water EC.     

Changes in Polyamine Titer in Rice Seedlings Following NaCl Salinity Stress

Seedlings of four rice cultivars differing in salt tolerance were raised in sand cultures under increasing levels of NaCl salinity and metabolic levels of total polyamines, spermidine, spermine, agmatine and the diamine putrescine were determined in roots and shoots during 5-20 days growth period. Salinity caused a remarkable increase in total polyamines level in rice seedlings. At similar level of salinity roots as well as shoots of salt sensitive cvs. Ratna and Jaya showed higher level of total polyamines than tolerants. Salinity of 14 dSm⁻¹ NaCl caused more than 2 times polyamine level in shoots of sensitive cultivars compared to tolerants. Accumulation of polyamines was greater in salt stressed shoots than roots. In nonsalinized seedlings there appeared a gradual increase in putrescine level during 5 to 20 days growth period. Salt treatment caused sharp increase in putrescine level in all cultivars, however under similar level of salinization salt stressed seedlings of sensitive cultivars had higher putrescine level than tolerants. In nonsalinized seedlings of sensitive cultivars spermidine level increased gradually during 5 to 20 days growth period whereas a decline in the level was observed in seedlings of tolerant cultivars during this period. Higher level of salinity caused marked increase in spermidine level in sensitive cultivars. Specially during 5 to 10 days of growth salinity caused increase in spermine level in seedlings of sensitive cultivars. In all cultivars salt stressed seedlings had higher agmatine level compared to non-stressed. Salinity led to greater accumulation of certain unidentified polyamines in seedlings of sensitive cultivars. Increased levels of total polyamines, putrescine, spermidine and unknown polyamines in rice seedlings under salinization suggest their possible role in combating the adverse effects of salinity stress.     

Genomewide association analysis of salt tolerance in soybean [Glycine max (L.) Merr.]

Salinity is a common abiotic stress causing soybean [Glycine max (L.) Merr.] yield loss worldwide. The use of tolerant cultivars is an effective and economic approach to coping with this stress. Towards this, research is needed to identify salt‐tolerant germplasm and better understand the genetic and molecular basis of salt tolerance in soybean. The objectives of this study were to identify salt‐tolerant genotypes, to search for single‐nucleotide polymorphisms (SNPs) and QTLs associated with salt tolerance. A total of 192 diverse soybean lines and cultivars were screened for salt tolerance in the glasshouse based on visual leaf scorch scores after 15–18 days of 120 mM NaCl stress. These genotypes were further genotyped using the SoySNP50K iSelect BeadChip. Genomewide association mapping showed that 62 SNP markers representing six genomic regions on chromosomes (Chr.) 2, 3, 5, 6, 8 and 18, respectively, were significantly associated with salt tolerance (p < 0.001). A total of 52 SNP markers on Chr. 3 are mapped at or near the major salt tolerance QTL previously identified in S‐100 (Lee et al., 2014). Three SNPs on Chr. 18 map near the salt tolerance QTL previously identified in Nannong1138‐2 (Chen, Cui, Fu, Gai, & Yu, 2008). The other significant SNPs represent four putative minor QTLs for salt tolerance, newly identified in this study. The results above lay the foundation for fine mapping, cloning and molecular breeding for soybean salt tolerance.     

棉花耐盐机理与盐害控制研究进展

综述了棉花耐盐机理、耐盐性鉴定方法和盐害控制技术的研究进展。棉花耐盐机理与一般植物存在着较大的差异,对盐分胁迫下的植株体内离子分布、细胞膜结构和稳定性以及渗透压调节作用等方面进行了探讨,总结了运用传统育种和现代生物技术改良和提高棉花耐盐性方面取得的进展。此外,提出了从棉花品种、栽培技术、种子引发技术和土壤改良等方面盐碱地植棉的综合技术体系。     

梯度滨海盐土对费菜生长指标及Na+、K+分布的影响

为探明滨海盐土对费菜生长发育的影响,掌握其盐碱土壤栽植下的耐盐特性,通过3、5、7、9、 11 g/kg等5个梯度的滨海盐土处理,对费菜生长指标及Na⁺、K⁺分布等进行研究。结果表明,随着盐分升高,株高、分枝、鲜重、干重均减小,≥7 g/kg盐分对费菜生长具有较大抑制,但盐分达到11 g/kg植株仍能继续生长;≥9 g/kg高盐分显著抑制地上干物质积累,对地下部生物量影响明显小于地上部。随着盐分升高,根、茎、叶中Na⁺的含量有升高的趋势,从部位含量看,茎>叶>根;随着盐分含量升高,叶中的K⁺含量逐渐减少,根、茎有升高趋势,从部位看,茎、叶是根的3倍;随着盐分浓度升高,根、茎、叶的Na⁺/K⁺比值具升高趋势,≤9 g/kg盐分胁迫下,根保持高Na⁺/K⁺比值,是茎、叶的近4倍。低于7 g/kg盐土对费菜影响不大,其耐盐性可能与宿根特性及茎叶结构有关。费菜集食用、园林于一体,由于其耐盐性强,可在滨海盐碱区种植应用。     

Multi-trait stability index: A tool for simultaneous selection of soya bean genotypes in drought and saline stress

Drought and salinity are the main limiting environmental factors that restrict the establishment of soya bean plants. In order to recommend genotypes for cultivation under adverse drought and saline stress conditions, multi-environment trials (MET) are needed. However, MET analysis is usually performed considering a single trait, which provides lower reliability in recommending genotypes when compared to multi-trait analysis. Thus, this study was carried out to investigate the stability of multi-trait stability index (MTSI) in 46 soya bean cultivars under the effects of drought and saline stress on seed germination and initial seedling growth. Drought and saline stresses were imposed by seed exposure to −0.20 MPa iso-osmotic solutions with polyethylene glycol—PEG 6000 (119.6 g/L) or NaCl (2.36 g/L) for 12 days at 25°C. The germination rate, seedling length and seedling dry matter were measured. We showed here how genotypic stability can be quantified by MTSI when comparing drought and salinity conditions in relation to non-stressful environment (control) and how this index can be employed under different conditions. When considering the index for multiple environments, we can select as the most stable genotypes TMG 716 RR, FPS Antares RR, AS 3610 IPRO, NS 7300 IPRO and FPS Solar IPRO among the 46 tested genotypes. Owing to high stability and gains with selection verified for these genotypes under salinity and drought conditions, they can be used as genitors in breeding programs aimed at obtaining offspring with higher resistance to antibiotic stresses.     

Identification and Characterization of Salt Tolerance of Wheat Germplasm Using a Multivariable Screening Approach

Salinity is one of the major limitations to wheat production worldwide. This study was designed to evaluate the level of genetic variation among 150 internationally derived wheat genotypes for salinity tolerance at germination, seedling and adult plant stages, with the aim of identifying new genetic resources with desirable adaptation characteristics for breeding programmes and further genetic studies. In all the growth stages, genotype and salt treatment effects were observed. Salt stress caused 33 %, 51 % and 82 % reductions in germination vigor, seedling shoot dry matter and seed grain yield, respectively. The rate of root and shoot water loss due to salt stress exhibited significant negative correlation with shoot K⁺, but not with shoot Na⁺ and shoot K⁺/Na⁺ ratio. The genotypes showed a wide spectrum of response to salt stress across the growth stages; however, four genotypes, Altay2000, 14IWWYTIR‐19 and UZ‐11CWA‐8 (tolerant) and Bobur (sensitive), exhibited consistent responses to salinity across the three growth stages. The tolerant genotypes possessed better ability to maintain stable osmotic potential, low Na⁺ accumulation, higher shoot K⁺ concentrations, higher rates of PSII activity, maximal photochemical efficiency and lower non‐photochemical quenching (NPQ), resulting in the significantly higher dry matter production observed under salt stress. The identified genotypes could be used as parents in breeding for new varieties with improved salt tolerance as well as in further genetic studies to uncover the genetic mechanisms governing salt stress response in wheat.