soils occupy about 10% of the world’s arable land. Soils are
either naturally affected by salinity (costal and inland), or
by mismanagement of irrigation water that builds up salt
levels (secondary salinity). About 50% of irrigated land is
affected by secondary salinity, and the salinity of arable
lands is steadily increasing. Therefore, we urgently need to
improve and develop salt-tolerant crops.
initiative to develop salinity-tolerant sorghum and pearl
millet, two ICRISAT mandate crops, is supported by the OPEC
Fund for International Development in collaboration with the
International Center for Biosaline Agriculture (ICBA, Dubai).
The work, initiated in mid 2002, has identified 17 sorghum and
11 pearl millet entries showing high tolerance to salinity,
and 15 sorghum and 26 pearl millet entries that were very
sensitive. The methodology involved growing plants in potted
soils with 250 mM sodium chloride solution added to field
capacity before sowing (resulting soil ECe 18.1 dS m-1).
Harvests were made before anthesis and the selection was based
on biomass production. The behavior of genotypes in glasshouse
conditions at ICBA and at ICRISAT were largely similar.
The salinity screening facility at
of the widely cultivated varieties and parental lines of
widely cultivated hybrid sorghum were found to be tolerant to
soil salinity. For example, variety ICSV 112 which is released
and adopted in many countries in Asia, Africa and Latin
America; drought-tolerant variety S 35 which is popular in
western and central Africa; and a post rainy season variety,
NTJ 2, which is also good for fodder.Similarly, several
restorer lines (ICSR 90017, ICSR 56, ICSR 196, and ICSR 160)
and A/B lines (ICS A/B 276, ICS A/B 300, ICS A/B 583 and ICS
A/B 699) are parental lines of commercial hybrids.
pearl millet, several parental lines of commercial hybrids
were found to be tolerant to highly tolerant of soil salinity.
These include restorer lines such as ICMP 451 and HTP 94/54
(dual-purpose type); ICMR 356, and RIB 3135-15(drought tolerant);
and maintainers of A-lines such as 841B and ICMB
screening procedures were developed, which allow the
characterization of a large number of individuals – a
requirement in molecular marker identification. The sodium and
potassium contents and their ratios in shoots is a promising
trait for salinity tolerance (less sodium and more
potassium = higher tolerance). Non-destructive methods of
measuring salinity tolerance are being investigated to
phenotype mapping populations. Identification of molecular
markers for salinity tolerance, which has not yet been
achieved for pearl millet and sorghum, is in progress.
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