We have large numbers of germplasm including highly salt tolerant lines 'Pokkali'. We failed to grow even under 8 dS m-1 from seedling stage to harvesting stage. Even the rice genotypes tolerant to reproductive stage salt stress give nothing except dry staff.
Though in classification many cereals including rice are listed as tolerant, no cereals can be grown at above 8 dS m-1. Probably the screening procedures followed were either based upon short term study or methodologies were wrong. Thus it is highly desirable to screen all the cultivars at 8-12 dS m-1 and recommend to farmers for its cultivation in saline soils.
In Iran, Esfahan, we cultivated rice in this EC ( stage:after transplanting). Off-course yield decreased deeply. Also some of Cymbopogon sp. can grow.
In our experimental we use genotypes from Iran also. While screening for reproductive stage salt tolerance we try o impose salt stress at reproductive stage with 8 dS-1. When we try to identify genotype tolerant to seedling stage we impose 12 dS m-1 and compare the results with susceptible genotype. Thanks for the information.
Imposition of Salinity at various stages is misleading in screening process as we are finally going the recommend the genotypes/cultivars to farmer for that particular salinity level. In general germination and seed development are very crucial stages. Our efforts in screening groundnut cultivars reight from germination to harvest are available on the researchgate.
1. Identification of groundnut (Arachis hypogaea L.) cultivars tolerant of soil salinity. Journal of Plant Nutrition 2010. 33(12):1761-1776
DOI 10.1080/01904167.2010.503779
Article Identification of groundnut (Arachis hypogaea L.) cultivars ...
2. Screening and selection of groundnut genotypes for tolerance of soil salinity May 2008 Australian Journal of Crop Science 1(3):69-77.
[PDF] from researchgate.net
Article Screening and selection of groundnut genotypes for tolerance...
Such studies are required in all the crops for final recommendations of a few genotypes for farmers. The same could also be used in the breeding programme.
Rice lines tolerant to salt-stress at seedling stage generally is not tolerant at reproductive stage. Genotypes with Saltol is not tolerant at reproductive stage. Genes differ for the stages. Where genes set are different, we need different screening technique. I am finding so many publications in high impact journals on salinity tolerance where authors got good grain yield at 12 dS-1 or higher concentrations and they imposed salt stress at seedling stage and continued up to harvest.
Yes.. the effect of salinity differs for various crops. For groundnut if consider farmers point of view it is quite pertinent that a genotype should have a particular threshold level of salinity tolerance for all stages before it can be recommended for farmers. But, again the level of salt stress may vary considerably throughout the growth period of the crop due capillary rise of salt when rainfall is not sufficient or dilution of salt concentration due to sudden rainfall.
For rice, the situation is little bit different particularly cultivars for coastal saline ecology, where the genotype may not face salt stress at early stages but suddenly it can appear during the reproductive stage. For that reproductive stage salt tolerance is critical. Though we have a few genotypes with good vegetative salt tolerance, but unfortunately we don't have good materials for reproductive stage salt tolerance as the mechanism differs hugely between these two stages.
Dear Dr Sarkar and all the researchers
I fully agree with your comments and upvote for the same. Now , as we people are mature enough and working for the farmers (not for the sake of publications) alone, our primary duty is to redefine the tolerance based on the throughout crop season salinity which is useful for the farmers. The rice lines tolerant to salt-stress at seedling stage if not tolerant at reproductive stage means it is not tolerant. Also a genotypes with Saltol if not tolerant at reproductive stage means it is a fake research (what for we have introduced gene?) and we should discourage such things for the benefit of farmers and society. As there are many publications in high impact journals on salinity tolerance where authors got good grain yield at 12 dS-1 or higher concentrations it is high time to revisit the same and taking all the genotypes and recommend only the suitable one for the farmers. There should be transparency in research as we are being paid for the same.
Trying to develop rice variety tolerant to both seedling and reproductive stage is going on in our Institute and elsewhere. However, we have to understand the basic Physiology of tolerance. If mechanism is different we have to accept it. It is really high time to revisit the different publications. One is publication for publication shake, another is the publication with useful information that works for farmers either directly or indirectly.
Dear Dr Shahin Imran,
As a scientist please share the information in English and also give the assurance that these were grown in 10-12 DS/m EC throughout the crop. Whether the technology has gone to farmer field?
We have tested both Bina dhan 8 and 10, but in our screening we found severe yield reduction even in 8 dS m-1 ECiw, when imposed specifically at reproductive stage.
We tested both Binadhan 8 and 10. Both the varieties tolerant to salinity. But one can't get any yield if salt stress is given at seedling stage with 12 dS m-1 and continue up to harvest.
As the salinity has different effects in different stages, thus it is very difficult to grow rice at such high salinity from seedling to harvest. Another thing is that different genes and proteins expressed at different stages under salinity so the plant will face stress at all the stages and that will push all the machinery towards survival that finally leads to poor development and yield.
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