PEG is used for in vitro selection for drought. This is just to select putative mutants, and finally they have to be tested initially in the greenhouse. In my mind, soil moisture is crucial for validating drought tolerance.. For flood tolerance, you will have to submerge plants completely under the water, and select the surviving plants and follow further.

Myat; what results did you get with peg selection?

I think the best method to screen for flooding tolerant plants/mutants is to submerge the plants in water for a specific period (few days) and then select the most tolerant one.

You mean water logging tolerant. For that you have to test under actual water logging conditions by flooding the few days old crop for few days and the real tolerant types can be selected which can be confirmed under lab conditions. We are doing experiments with pigeonpea crop

I am conducting an experiment of screening for water-logging tolerance in pigeonpea at ICRISAT , for screening genotypes for flooding tolerance we follow the same procedure of submerging the plants with water for specific days in field ( mostly it is 7- 8 days for most of the crops)and then selecting those which are surviving .To confirm it we can also go for anatomical studies like study of arenchyma cells/lenticles development etc . As these adaptations in plants allow them to survive flooding stress.

>>Luis Ramos >> we use PEG for in vitro selection and green house for drought in rice mutation breeding and we have some putative mutants. >> Shri Jain, Sarvjeet Singh, Sarvjeet Singh, Inderjit Singh, Inderjit Singh and Anupama Hingane, thank you all. If so, there is no way for in vitro selection of for flooding tolerant plants/mutants.

In vitro we can grow plants in the liquid nutrient medium, and they grow better, and used for large-scale shoot production in a bio-reactor. One could try submerging in vitro -plantlets or seedlings in sterile water for few days and transfer them on solid nutrient medium for recovery. To my knowledge, flooding tolerant plants have not recovered in vitro

Myat; I have been using peg for some time and found some amazing results, though didn't published yet. Hve you published your results? Like to see how did you used peg...

Almost all rice cultivars are injured when completely flooded or submerged for several days. However, few have been found to be comparatively more resistant. This feature is referred to here as “tolerance”. Fairly greater ability to tolerate flooding/ submergence for more than a few days is rare. So, I would like to suggest you the best method to monitor for flooding/ submergence tolerant mutants is to submerge the plants in anoxia condition for a particular period (say a few hour or day) and then opt for the most tolerant one.

Dear Myat, Generally field screening is followed for submergence tolerance studies. One article was published in 1990 on glass house method of screening. You can see the article for more information. The article is 'Submergence tolerance of rice – A new glasshouse method for the experimental submergence of plants' in Physiologia Plantarum Volume 80, Issue 4, pages 642–646, December 1990.

There is another procedure done at Paddy Breeding Station, Tamil Nadu Agricultural University, India for submergence screening. I don't know whether it is published or not, but you can try.

The evaluation of rice genotypes for submergence tolerance was performed under green house conditions. Rice plants were under normal conditions with six pots for each variety. After 21 days, a set of three pots for each variety was submerged in 1.5 m height plastic tanks filled with water. Plants were monitored at every 3 days interval (3rd, 7th, 10th, 14th days after submergence and 10 days after de-submergence) and leaf samples were collected for carbohydrate estimation. After 14 days of submergence, pots were taken-out from the tanks and evaluated for their level of tolerance. Recovery ability of genotypes was assessed after 10 days of de-submergence.

Please update your results. Thanks.

>>Luis

no Sir, we have no Publication about that..

Thanks Myat;

would you please tell how did you use peg on your material?

Using low oxygen atmosphere in airthigt vessel or adding metabisulfite, checking the effect with an oxygen electrode

Would you have a reference on this, Guido? thanks!

In our recent publication we have identified a drought tolerant mutant screened under PEG stress in hydroponic culture. Also we described the germination test in PEG stress. This publication may help you the PEG stress researchers. Below is the link of our publication. 

http://aobpla.oxfordjournals.org/content/early/2015/03/27/aobpla.plv023.abstract

• For screening against flooding or water logging, you may use in vitro or in vivo techniques. In case of in vivo screening, sub-merge the seeds in water for about 5 to 6 days and then place in petri plates for germination and then identify flooding tolerant seedlings and grow them in pots for maturity. In case of in vitro screening, grow plants in pots and place the pots r(after 25 to 30 days of sowing) in water for about 4 to 5 days and  then remove the pots from water. The surviving plants can be identified as flooding tolerant.