Breeding for salt tolerance, BSKKV

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Breeding for salt tolerance


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Breeding for salt tolerance Presented by, Mr. AMBAVANE AJINKYA RAJENDRA DBSKKV, Dpoli S eminar on ,


Introduction All soils contain some salts but when soils contain excessive concentrations of either soluble salt that are not held on soil exchangeable sites or exchangeable sodium or both, they are called salt affected soils (Conway 2001; Denise 2003; Jim 2002). Saline, Sodic , and Saline- sodic Soil (Gonzalez et al., 2004) Sodic soils are low in soluble salts than saline soils but high in exchangeable sodium (Jim 2002 & Pam 2002). Saline soils contain excessive concentrations of water-soluble salts (Conway 2001; Denise, 2003). Saline- sodic soils contain both large amounts of water-soluble salts and exchangeable sodium (BPMC 1996).

Types of salt-affected soils:

Types of salt-affected soils Salt affected soil EC (dSm -1 ) ESP (%) SAR pH Saline >4 <15 <13 <8.8 Sodic <4 >15 >13 8.5-10.5 Saline- Sodic >4 >15 Variable >8.5

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Sodic soils Salt deposition Salt affected soil Saline soils i ) ii) iii)

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Saline- Sodic soils


MANAGEMENT OF SALT AFFECTED SOILS Agricultural utilisation of salt affected soils can be improved by the following two approaches- 1. reclamation- removal of soluble salts or excess exchangable Na. Leaching of soluble salts- saline soils Application of soluble amendments- alkali soils 2. management of soil- choice of crops, method and time of planting, irrigation, and development of salt- tolerent varieties.

Why do we need salt tolerant cultivars?:

6.73 million ha of land is affected by salinity and alkalinity problem in India ( Sodic soils 3.77 million ha Saline soils 2.96 million ha) 25 % of ground water used for irrigation is either saline or brackish At global level, total 831 million ha is affected by sodicity (434 million ha) and salinity (397 million ha) 10 million ha of land are lost because of salinity caused by irrigation each year (George E. Brown Jr. Salinity Laboratory, 2006) The United Nations Environment Program estimates that approximately 20% of agricultural land and 50% of cropland in the world is salt-stressed (Flowers and Yeo , 1995). In all types of salt affected soil yield reduction varing from 37 to 70 % Why do we need salt tolerant cultivars?

Breeding for salinity resistance:

Breeding for salinity resistance In india , Central soil salinity research institute, Karnal has the madate for breeding salinity resistance varieties of crop plants. Effect of salinity- Plants growing in saline conditions are subjected to 3 types of stress- 1. water stress generated by the osmaticum ie salt insolution 2. mineral toxicity stress caused by the salt 3. disturbance in the mineral nutrition of the plant

Sources of Slinity resistance -:

Sources of Slinity resistance - Cultivated varieties Germplasm collection Related species Somaclones Transgenes

Breeding approaches for salinity resistance:

Breeding approaches for salinity resistance Salinity resistant rootstocks Selection Hybridization Interspecific hyridization Cell selection Genetic engineering

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Salt tolerant rice variety, CSR13, with 25% gypsum requirement and a local variety without gypsum Degree of salt stress different varieties IR65192 IR29 A) B) Salt tolerant variety Local variety

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What are the symptoms of salt stress? Low to moderate salt stress affect the plant growth rate and causes symptoms associated with plant morphology, physiology or biochemistry. Extreme high salt stress kills the plant

Morphological symptoms :

Morphological symptoms 1) White leaf tip followed by tip burning (salinity) 2) Leaf browning and death ( sodicity ) 3) Leaf rolling 4) Stunted plant growth 5) Low tillering 6) Spikelet sterility 7) Change in flowering duration (no flowering) 8) Patchy growth in field 9) Less florets per panicle, low 1000 grain weight and ultimately low grain yield

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( Papery) Spikelet sterility is an effect of salinity at reproductive stage Extreme high salt stress conditions kills the plant II) I)

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White leaf tip followed by tip burning (salinity)

Physiological and biochemical symptoms :

Physiological and biochemical symptoms Affected plants show High Na + transport to shoot Preferential accumulation of Na + in older leaves Lower K + uptake Low Na/K ratio to maintain ion balance High Cl - uptake Lower fresh and dry weight of shoot and roots Low P and Zn uptake Change in esterase isozyme pattern Increase in Polyamine levels

What are the breeding methodologis?  :

What are the breeding methodologis ? I) Conventional Breeding Introduction, selection, hybridization, mutation Pure line selections from local traditional cultivars : Eg : Rice: Damodar (CSR 1), Dasal (CSR 2), Getu (CSR 3), Hamilton Pedigree method : Rice: CSR10, CSR13 CSR23, CSR27, CSR30, CSR36.

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Difficulties encountered in Conventional breeding approach: Linkage drag:- many negative characters in the traditional landraces Breeding lines are less tolerant than the donor parents because tolerance is a complex Gregorio and Senadhira (1993) showed that salinity tolerance (low Na-K ratio in the shoot) is governed by both additive and dominance gene effects, large environmental effects and low narrow-sense heritability (19.18%).

III) Non conventional breeding :

III) Non conventional breeding A) Somaclonal variation: Pokkali type of rice varieties are low yielding but highly saline tolerant grown in coastal areas of Kerala State. B) F 1 anther culture (AC)-derivatives : i ) IR51500-AC-17(CSR 21), IR511485-AC-1 and AC6534-4 for salinity ii) AC6533-3 for alkalinity iii) AC6534-1( CSR 28) for dual stress C) Molecular markers Marker Assisted Selection (MAS): a supplementary tool to conventional breeding

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AN IDEAL HIGH YIELDING SALT TOLERANT VARIETY SHOULD BE Good Na + Excluder (shoot or leaf) Highly tissue tolerant High uptake of K + per day Low Cl - uptake Low Na + / K + ratio Good initial vigour Agronomically superior with high yield potential (plant type + grain quality)

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What are the different kinds of tolerance mechanisms to salt stress in plants? 1. Under salt stress conditions, the crop plants either try to avoid the stress, which is indeed not an actual tolerance mechanism or 2. Employ the following mechanisms to overcome the  salt damage in a sequential adaptations Seedling vigor Minimize the initial entry of salt from roots Intra cellular compartmentation Plant level transport of salt and its compartmentation Tissue tolerance

Physiological mechanisms that explain salt tolerance: :

Physiological mechanisms that explain salt tolerance: 1. Seedling Vigor (fast growth): Traditional varieties are more vigorous and tolerant to salt stress. Fast growth help dilute salt concentration in plant tissue 2. Minimize the initial entry of salt from roots ( Sodium exclusion) : Tolerant cultivars take less salt through their roots than susceptible cultivars 3. Compartmentation in old leaves and structural tissues: Tolerant varieties maintain lower concentration of salt in younger tissue than in older leaves, stems and leaf sheaths. This help maintaining growth of young tissue and survival 4. Tissue tolerance

Relative salt tolerance of crop plants based on yield:

Sensitive Moderately Sensitive Moderately Tolerant Tolerant Apple Cabbage Barely (forage) Barely (grain) Carrot Cowpea Sorghum Cotton Okra Cucumber Safflower Bermuda grass Onion Potato Soy bean Sugar beet Strawberry Rice Wheat Date Lemon Radish Beet Wild rye Relative salt tolerance of crop plants based on yield

REFerences- :

REFerences - Book Plant Breeding Principles and Method by B. D. Singh Article 1) Breeding for abiotic stress tolerance - Salt tolerance as a case study By G. Padmavathi Senior Scientist, Plant breeding Directorate of Rice Research Hyderabad, India 2) Salt Stress Tolerance of Plants Shuji Yokoi, Ray A. Bressan and Paul Mike Hasegawa Center for Environmental Stress Physiology, Purdue University1165 Horticulture Building, Purdue University, West Lafayette, IN 47907-1165 USA 3) Mineral Nutrition of Crop Plants in Salt Affected Areas in India A.K. Singh*, Ali Qadar , N.P.S. Yaduvansh *ICAR, New Delhi, CSSRI, Karnal 4) Breeding for Salt Tolerance in Rice R.K. Singh (PBGB, IRRI) Internet Source

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