Background salinity is a major abiotic stress limiting yield in many parts of the world. Since there is a cross talk between these abiotic stresses, identification of common andor overlapping regulatory elements is pivotal for generating rice. Niab 6, bg 4024, basmati 370, and ir 1561 with different salt tolerance were grown in yoshida nutrient solution without and with 100mol. Exploring novel genetic sources of salinity tolerance in rice through. Soil salinity is a major environmental constraint to crop production with negative impacts on growth rates, tillering and seed production. Vegetable crops water salinity tolerance ecw this table indicates the yield reductions that could be expected when various vegetable crops are irrigated. Modifying sodium transport to improve salinity tolerance of commercial rice cultivars oryza sativa l. These mechanisms can also be further classified into ion exclusion, osmotic tolerance and tissue tolerance roy et al.
Salinity tolerance in rice has been a target for im. Assessment of salinity tolerance in rice using seedling. The rice genotypes differed significantly for salt tolerance at seedling. Shannon flood irrigation practices that are commonly used in california et al. Genomewide association study for salinity tolerance at. Rice, a staple food crop, is often subjected to drought and salinity stresses thereby limiting its yield potential. Salt tolerant and sensitive rice varieties display. Breeding for salinity tolerance in rice 1985 akbar, m. This knowledge is necessary for transferring high salt tolerance into highyielding rice cultivars. Different cultivars of a species have different tolerance levels and the tolerance of a species may change with its stage of growth. Overexpression of osmyb481, a novel mybrelated transcription factor, enhances drought and salinity tolerance in rice, plos one, 2014, volume 9, issue 3, doi. Of which, 52 primers in the saltol region were checked with the two parents varieties to identify polymorphic primers for screening the saltol region of the breeding. Course material from the usda nrcs training course, management of saline and sodic soils 1991, a series of five training notes by dr.
There was a wide range of variation in salinity tolerance at seedling stage among the 176 temperate japonica accessions. Salinity tolerance loci revealed in rice using high. Here, we conducted a genomewide association study gwas of salt tolerance based on exome sequencing of the thai rice accessions. Rice is a salinity sensitive crop, but the level of salinity tolerance varies in different varieties of rice 10. Rice plants generally tolerate salt by mainly two mechanisms, ion exclusion and osmotic tolerance munns and tester, 2008. Electro physiologically, increasing salinity reducedthe electrical pd of plant leaves. Drought is one of the most common environmental factors that limit crop productivity, especially in asia where at least 23 million hectares of rice 20% of the total world rice area are drought prone 4. Here, the indica rice sea rice 86 sr86 seedlings showed higher tolerance than ordinary rice varieties in saline soil, and a dominant effect on salinity sensitivity was demonstrated by genetic analysis. Salinity indicator species vary from region to region and with the level of. Identification and validation a major qtl from sea rice. Taken together, these results show that saltadapted pokkali rice varieties are powerful sources for the identification of novel endophytes, which can be used to confer salinity tolerance to. Plants differ greatly in their tolerance of salinity, as re.
Effect of salinity on chlorophyll concentration, leaf area, yield and yield components of rice genotypes grown under saline environment y. We constructed bulked segregant analysis pools using f2 populations from parents dianjingyou 1 as the recipient and sr86 as the donor. Salinity is considered as one of important physical factors influencing rice production. Please click on the icon to open this manual in pdf format. The main aim is to fully understand the salt tolerance mechanisms and to identify the sensor for sodium. Effects of salinity stress on growth, chlorophyll content and. This study focus on developing new salinity tolerance and high yielding rice lines, using markers assisted backrossing mabc. Downregulation of the dst transcription factor using.
The genetic base of salttolerant rice donors being used in breeding is relatively narrow and needs broadening to breed varieties with wider adaptation to. Stress and disease tolerance irri rice knowledge bank. Salinity effects on seedling growth and yield components of rice. Sixteen rice genotypes were used in this case study. Identification and validation a major qtl from sea rice 86. Determining soil salinity in the field from measurements of. Drought andsa linity stress tolerance and adaptation in rice plants have been improved by engineering various transcriptionfactors, genes related to signalling pathway, compatible solutes and accumulation of antioxidants. While rice growing has contributed to the high water tables, the crop can also be used in the reclamation of saline soils, particularly if locally adapted salt tolerant.
Salt stress tolerance is a complex trait, so the qtls related with salt tolerance have significant role in understanding the stress response and generating stresstolerant plants gorantla et al. Aris hairmansis a thesis submitted for the degree of doctor of philosophy school of agriculture, food and wine faculty of sciences the university of adelaide february 2014. Salt stress, a major plant environmental stress, is a critical constraint for rice productivity. Salinity tolerance loci revealed in rice using highthroughput noninvasive phenotyping. Rhoades, usda ars salinity laboratory, riverside, california. Salinity effects on seedling growth and yield components. Salinity tolerance in irrigated crops nsw department of. To investigate the protective effects of proline against salt stress, saltsensitive brri dhan29 and moderately salttolerant brri dhan47 rice cultivars were. However, based on the visual evaluation, only 3 of the evaluated accessions nep ngau from vietnam, bai mang ai zhong from china and shinchiku iku 97 from taiwan were as tolerant as the tolerant check. Salinity tolerance in australian wild oryza species varies.
Tahir nuclear institute for agriculture and biology, faisalabad, pakistan abstract. However, rice is very sensitive to salinity and is the most salt sensitive cereal crop with a threshold of 3 dsm1 for most cultivated varieties. The purpose of this study was to establish the relative importance of different traits associated with salinity tolerance in rice and to identify new quantitative trait loci qtl conferring tolerance to salinity at seedling stage. But the concentrations of na, zn, cu and mn increased. Many qtls for salinity tolerance have been identified 1124. However, most of the qtls were identified in biparental populations derived from indica accessions such as pokkali and. Drivers of rice cropping patterns and rice damage by salinity in the coastal delta, cropping patterns and rice damage are strongly driven by level and timing of salinity intrusion, amount and timing of rainfall, water structures, food. Salinity effects on seedling growth and yield components of rice linghe zeng and michael c.
Many qtls have been identified in rice for salinity tolerance contributing traits and majority of them have been reported on chromosome 1. Salinity tolerance is a complex trait controlled by quantitative trait loci qtls. K rice genome project, and this set included 203 temperate japonica rice accessions. In the present study, we screened eight tolerant, eight semitolerant and three sensitive rice genotypes for salinity as well as alkalinity tolerance in saline and.
The difference of electrical pd on each variety of the rice in different levels of salinity can be used as a screening tool for rice salinity tolerance. Pdf characterizing the saltol quantitative trait locus. The yield potential of this variety is 8 tonha under. Assessing trait contribution and mapping novel qtl for. Evaluating rice for salinity using potculture provides a systematic. Response regulators 9 and 10 negatively regulate salinity. For example, breeders have long made use of the high salinity tolerance of a few landraces, such as nona bokra and pokkali. Screening of salinity tolerance of rice at early seedling stage. Due to the large genetic variability, rice varieties possess different degrees of salt. The extent of salinity varies depending upon the plant growth stage. The effect of salinity on dry matter production varied from cultivar to cultivar. Genomewide association study for salinity tolerance at the. Thus, assessing the cumulative effect of morphophysiological traits can help to build a comprehensive protocol to evaluate rice genotypes and understand plant mechanism s for salinity tolerance.
Tagging and validation of ssr markers to salinity tolerance. Four simple sequence repeats ssr markers rm493, rm10793, rm3412 and rm10791 found in the saltol locus in chromosome 1 were used for molecular analysis. Of the cereals, rice oryza sativa is the most sensitive and barley hordeum vulgare is the most tolerant figure 1. Salinity laboratory, usda ars riverside, ca abstract the capability of crops to grow on saline soils varies among species and depends on the concentration of salts presen t in the rootzone and on various environmental and cultural conditions. We evaluated the salinity tolerance of a panel of 235 temperate japonica rice accessions genotyped with 30,000 snp markers. Introgression the salinity tolerance qtls saltol into as996. Na, ca, mg, cl, and so4 are the major ions involved. Screening six varieties of rice oryzasativa for salinity. Rnai mediated drought and salinity stress tolerance in plants. Susceptibility and tolerance of rice crop to salt threat plos.
This knowledge is necessary for transferring high salttolerance into highyielding rice cultivars. Information on the relative tolerance of different. Salinity tolerance in rice varieties at different growth stages. The difference of electrical pd on each variety of the rice in different levels of salinity can be.
Irri has already using marker assisted selection for saltol qtl, responsible for seedling stage salinity tolerance in rice, to facilitate the breeding for salt tolerant cultivars. Effects of salinity stress on growth, chlorophyll content and ion accumulation in two indica rice oriza sativa l. In the present study we show that exogenous expression of antiapoptotic genes from diverse origins, atbag4 arabidopsis, hsp70 citrus tristeza virus and p35 baculovirus, significantly improves salinity tolerance in rice at the whole plant level. Previous studies in rice have suggested the use of several selection criteria to increase salinity tolerance 37,40. Soil salinity is widespread in riceproducing areas globally, restricting both vegetative growth and grain yield. Effect of salinity on chlorophyll concentration, leaf area. Pollen viability, number of unfilled and filled grain and grain yield per plant were evaluated. Characterizing the saltol quantitative trait locus for salinity tolerance in rice. An endophyte from saltadapted pokkali rice confers salt. The current study was aimed to investigate the mechanisms of salt acclimation in rice and reveal which stress cues are important for acclimationinduced salinity tolerance by using lower. However among the agronomically important cereals rice is the most sensitive to salinity. Pdf evaluation of salinity tolerance in rice genotypes. The panel was exposed to mild salt stress 50 mm nacl. Different salinity affects differently on electrical plant leaf pd of the six varieties of rice.
Aug, 2019 salinity is one of the most widespread abiotic stresses affecting rice productivity worldwide. Pdf salinity and salt tolerance improvements in thai rice. Pdf rice oryza sativa l is an important staple crop that feeds more than one half of the worlds population and is the model system for. Salinity is defined as the presence of excessive amounts of soluble salts in the soil usually measured as electrical conductivity, ec. Exploring novel genetic sources of salinity tolerance in rice. Salinity is one of the most widespread abiotic stresses affecting rice productivity worldwide. Improvement of salinity stress tolerance in rice mdpi. Introgression the salinity tolerance qtls saltol into. Thus, in breeding rice for saline environments, multiple stress tolerance traits must be considered. Salinity tolerance in irrigated crops 2 nsw department of primary industries, january 2017 note that one megalitre at ecw of 1 dsm contains about 640kg of salts. Pdf the effects of mild salinity and osmotic pretreatment. To this end, threeleafstage rice seedlings wild type and osrr9osrr10 mutant were exposed to 150. Modifying sodium transport to improve salinity tolerance of.
Total of 500 ssr markers on 12 rice chromosomes were screened for parental polymorphic markers. Salinity indicator species can be used to indentify a saline site, a waterlogged site, or a site that is both saline and waterlogged. In most of the cultivars, more damage is done at germination and early growth stages 11, indicating that salinity has negative effect on plant early growth stages. At all 3 stages, varieties differed in their degree of tolerance, but the order of tolerance varied considerably between stages. As996 variety was derived from the cross ir64oryzarufipugon, official released in 2002. Susceptibility or tolerance of rice plants to high salinity is a coordinated action of multiple stress responsive genes, which also interacts with other components of.
Identification and validation of qtls for seedling. Salinity symptoms department of primary industries. Tolerance to mild salinity stress in japonica rice. Shannon abstract reduction were observed scardaci et al. What is needed for the development of salt tolerant cultivars. Identification of molecular markers tightly linked to salt tolerant genes can serve as land marks for the physical localization of such genes facilitating marker assisted selection mas. In this study, we quantified the effects of salinity on rgr, tr and tue in. Genomewide association studies, seedling stage, salinity tolerance, candidate gene,temperate japonica background rice is grown worldwide in areas where temperatures are suitable and irrigation water is available. A good solution would be the development of an efficient screening methodology to identify genotypes possessing genes for salt tolerance. Assessment of salinity tolerance in rice using seedling based. Soil salinity harmful influenced germination characters of rice cultivars salinity is the main limiting factor that adversely affecting germination, growth and yield of rice. Assessing trait contribution and mapping novel qtl. Identification of cisregulatory elements associated with. Salinity has a significant impact on rice production in coastal, arid and semiarid areas in many countries, including countries growing temperate rice, such as kazakhstan.
Mechanisms of salinity tolerance in rice oryza sativa l. Dissecting the genetic loci controlling salt tolerance in rice for improving productivity, especially at the flowering stage, remains challenging. Salinity tolerance is an important quality for european rice grown in river deltas. Worldwide rice is grown on some 400 million hectares. However, the vast genetic variability reported in rice in response to salinity makes it amenable to genetic manipulation to further enhance its tolerance akbar et al. Singh, plant breeder at the international rice research institute, discusses the latest progress in salinty tolerance research in rice.
Salinity is not only a major environmental factor which limits plant growth and productivity, but it has also become a worldwide problem. Molecular characterization and identification of new sources. Improvement of salt tolerance in rice oryza sativa l. Exploring novel genetic sources of salinity tolerance in. Mar 30, 2015 however among the agronomically important cereals rice is the most sensitive to salinity. Salinity tolerance of selected temperate japonica rice accessions. Molecular characterization and identification of new sources of tolerance to submergence and salinity from rice landraces of coastal india volume 17 issue 3 r. Attempts to improve the salt tolerance of asian rice, oryza sativathe most salt sensitive of the major cereal cropshave met with limited success, due to the complexity of the trait and finite variation in salt responses among o. Effects of salinity stress on growth, chlorophyll content. Evaluating rice for salinity using potculture provides a. The concentrations of p and k in the tops of rice cultivars decreased with increasing soil salinity. Significant varietal differences were found in relation to salinity tolerance.
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