Status of salinity soils, breeding approaches for Salinity resistance

1. Breeding for salinity tolerance
CHANDANA, B. R.
Jr. MSc (GPB)
UAHS, SHIMOGA

2. • Stress:- factors of environment interfering
the complete expression of genotypic
potential
• Abiotic stress :- negative impact of non living
factors on the living organisms in a specific
environment

3. Major abiotic stresses

4. Characteristics of abiotic stresses
• Unpredictable occurrence
• Some stresses are impossible to manage
• One stress may increase or decrease the level
of another stress
• Differential response of plant sp. To a given
stress
• Effects generated by one abiotic stress may
overlap with some effects of another stress

5. Cramer et al.,2011

6. Losses caused by the abiotic stresses
• The progressive salinization of soil, estimated at around 20%
of irrigated land in world
(Ghassemi et al.,1995)
• It was estimated that approximately 70% of yield reduction
was due to abiotic stress
(Acquaah,2007)
• The estimated potential losses are 17% due to drought, 20%
due to salinity, 40% due to high temperatyure, 15% due to low
temperature and 8% due to other stresses
(Ashraf et al.,2008)

7. • A major challenge towards world agriculture involves
production of 70% more food crop for an additional
2.3 billion people by 2050 worldwide.
• Abiotic stresses generated by mineral salts affect
considerable proportion of the arable land and they
rank second after moisture stress.
• Loss of 30% arable land by 2025
• 50% by 2050.

8. • Salinity is one of the most serious factors limiting the
productivity of agricultural crops, with adverse
effects on germination, plant vigor and crop yield
• Salinization affects many irrigated areas mainly due
to the use of brackish water. Worldwide, more than 45
million hectares of irrigated land have been damaged
by salt, and 1.5 million hectares are taken out of
production each year as a result of high salinity levels
in the soil (R Munns & Tester, 2008 ).

9. High salinity affects plants
• Water stress,
• Ion toxicity,
• Nutritional disorders,
• Oxidative stress,
• Alteration of metabolic processes, membrane
disorganization,
• Reduction of cell division and expansion.
Hasegawa et al. 2000

10. Status of Soils
Regions Total area Saline soils Sodic soils
Mha Mha % Mha %
Africa 1,899 39 2.0 34 1.8
Asia, the Pacific
and Australia
3,107 195 6.3 249 8.0
Europe 2,011 7 0.3 73 3.6
Latin America 2,039 61 3.0 51 2.5
Near East 1,802 92 5.1 14 0.8
North America 1,924 5 0.2 15 0.8
Total 12,781 397 3.1% 434 3.4%
FAO Land and Plant Nutrition Management
Service

14. Salinity occurs through natural or human-induced
processes that result in the accumulation of dissolved
salts in the soil water to an extent that inhibits plant
growth.
Sodicity is a secondary result of salinity in clay soils,
where leaching through either natural or human-induced
processes has washed soluble salts into the subsoil, and
left sodium bound to the negative charges of the clay.

15. • Salinity can be overcome by
1)Soil reclamation : Costly, time consuming &
short lived
2)Resistance varieties : Less costly, more
effective, long lasting but require longer period
to develop.

16. Plants on the basis of adaptive evolution
classified
Halophytes (that can withstand salinity)
Glycophytes (that cannot withstand salinity and
eventually die).
Majority of major crop species belong to this
second category.

17. • Salinity stress involves changes in various
physiological and metabolic processes, depending on
severity and duration of the stress, and ultimately
inhibits crop production.
• Initially soil salinity is known to represses plant
growth in the form of osmotic stress which is then
followed by ion toxicity.

19. Plants response to environmental stress
Environ
mental
stress
Severity
Duration
number of
exposures
Combination of
stresses
Stress
characteristics
Plant characteristics
Organ or tissue
in question
Stage of
development
genotype
resistance
susceptible
Survival and
growth
Death
Response Result

22. Characteristics of plants to salt :
Land races more tolerant than high yielding
varieties
Salt tolerance capacity differs from species to
species
Different plants show differential response to
salinity

23. Sources of Salinity resistance
• Cultivated variety
• Germplasm collection
• Related species
• Somaclone
• Transgenes

24. Breeding approaches for Salinity
tolerance
• Use of resistant root stocks
• Selection
• Intervarietal Hybridization
• Interspecific Hybridization
• Cell selection
• Genetic Engineering

25. Classified based on Salt tolerance
1.High tolerant crops
Sugar beet, Barley, Cotton, Date palm, Asparagus
2. Moderately tolerant :
Barley, Rye, Sorghum , Wheat, Safflower, Soybean
3. Moderate Sensitive :
Rice, Corn , Foxtail millet, Cowpea, Peanut, Sugarcane,
Tomato, Potato, Radish, Cabbage
4. Extremely Sensitive :
Citrus, Strawberry, Melon, Peas, Carrot, Okra, Onion

27. • Rice – CSR-49, CSR 36, CSR 30 (basmati type),
CSR 27, CSR 23, CSR 13 and CSR 10, Mohan,
Lunishree
• Rice variety for coastal regions:- Butnath (CSRC(S)
5-2-2-5) and Sumati- CSRC-CSRC(S) 2-1-7
• Wheat :- KRL 213, KRL 210, KRL 19 and KRL 1-4
• Indian Mustard:- CS 56, CS 54
and CS52
• Chick pea (gram)- Karnal Chana 1
• Dhaincha (sesbania)- CSD 137 and CSD-123
Varieties identified for salinity tolerance