Stem water potential, relative water content, leaf mass area, chlorophyll stability index,

Chlorophyll content (SPAD), stomatal conductance (porometer), RWC, flag leaf senescence, duration of greenness are parameters I would propose. All characteristics were estimated on wheat flag leaves.

There are many startegies among plants. No sinlge answer is possible

I totaly agreement with Jaume. If you want, please, see my paper attached about it.

Follow the paper...

Article Cross-scale multivariate analysis of physiological responses...

Thanks dear all for suggestions and publications.

Accoring to my personal opinion, this question can be addressed in two main points of view, i.e. whether you are interested on the survival of the plants or getting a considerable yield even during the drought period. For the first case, it is better to consider the root characteristics, such as the total depth and the traits which limits the transpirational losses such as leaf hairs, cuticular thickness of the leaves etc. For the second case it is better to concentrate on the water use efficiency, relative water content , chlorophyll content etc.

Dear Thushari, thanks for the interesting opinion. i want to add recovery ability after drought to your notes.

If you want to screen the genotypes then go for replicated trial of the same genotypes in same environment. Grow them in PVC pipe with sand or other material which has less or poor water holding capacity, at the same time grow in normal land where there is sufficient water is available for growth and development. These will helpful when an individual is first time researcher in particular crop. Even you can go for screening with molecular markers, which will give accurate result (if they are reported by someone else) like SSR primers available for drought tolerance in Rice. Then go for mRNA expression study of treated (grown in PVC pipes), and controlled (normal land grown plant). These may again help in expression level study of drought-tolerance.

Thanks for all i will use all suggestions.

screening the advance cultures initially under drought simulated conditions, later evaluating the better ones in real drought conditions. The soil water holding capacity and other soil physical properties plays a vital role for screening of genotypes. The drought tolerant plants will have a dark dgreen leaves, more productive tillers in rice than its susceptible ones.

For screening of genotypes for drought tolerance under field conditions one has to raise experiment in controlled drought conditions as well as under irrigated conditions for comparison and take observations on various traits viz., root length, root volume, leaf water potential, root shoot ratio, proline content in leaf, pod set percentage, yield per plant or per plot.

In laboratory conditions one can use polyethylene glycol (PEG) method.

Rapid screening as suggested by Sarvjeet Singh PEG is very easy for lab study. Incase of field study, C13/C14 ratio & O16/O17 by IRMS (Infra Red Mass Spectrometry) might be easy and very fast screening

Root length, root volume, leaf water potential, root shoot ratio, proline content in leaf under drought tolerance conditions created artificially and selecting the efficient genotypes

Relative Water Content and photosynthetic efficiency are very quick and reliable one according to me. whereas for PEG study you need to do an exercise that at what negative osmotic potential you are going to screen and which is the best optimum negative osmotic potential to screen at for this has to go through the various previous articles or first screen germplasm in field, collect the data on negative osmotic potential and then rapid screen in lab will give the best results.

Thanks for all suggestions

Dear mehdi,I think measuring wilting percentage among genotypes is a quick and not expensive and realable tecnique. Because Those genotypes with better biochemical ,physiological and agronomical traits shows their actions in the apearance of the plants.Measuring for example antioxidants or other biotec methods needs economic supports but just with looking genotypes in fields and scoring them for wilting I think we can reach to tolerant genotypes.(Ofcourse this is my coversation with Dr Eric Ober about 5 years ago talking in sugar beet institute of Iran.He belived we can find tolerant genotypes of sugar beet with measuring wilting percentage of genotypes with scoring them.)

Dear Davood, what does it mean "wilting"?

Dear Zofia,Drought tolerant genotypes have higher relative water content(RWC) and higher turgid in their cells.These are because of a collection of biochemical and physiological traits that exist in drought tolerant genotypes.When leaves lose their water they lose their turgid and they go wilting.We can score these appearance of leaves from 1(higher turgur) to 5(minor turgor) and/if we corrolate these scores with seed yield or biochemical markers then we can find a good relationship.

Do you think, that it is possible for cereals?

I would suggest plant growth parameters like number of primary stem, number of branching levels, length of primary and secondary stems, leaf area, water holding capacity, leaf retention, and other laboratory studies like proline, antioxidants and Page

Dear Zofia,In crops with broad leaves like sugar beet is more suitable.I think in cereals is also possible.Wheat genotypes must be imposed drought stress and then scoring their wilting from 1 to 5.

I might also suggest measuring chlorophyll fluorescence to assess PSII efficiency (I used OSp1 from Opti-sciences).

thanks Catherine

I would suggest physiological parameters like relative water content (RWC), membrane stability index (MSI), yield stability index (YSI) and plant height stability index (PHSI). During my Ph.D. time based on these parameters i was identified some drought tolerance genotypes in chickpea. So, you can use these parameters also.

Thanks Hari

Dear Mehdi, sometimes it is necessary to preselect plants of interest before using them as experimental material. Smaller the size of experiments, higher the precision of the experiments and lower the required costs and labor. The easiest way is good observation: You may check the leaves for their less number of stomata as well as their position. Lower side of leaves and being in wrinkle are preferred. The thickness of cuticle and wax layer is another trait. The morphology of root system is another important point. Little leaves are preferred to broad leaves. Hairy plants are better than bald ones. less leaf number is better than high leaf number. More roots and well distributed deeper roots are better than more superficial roots or one or few number of roots.

Thanks dear Babak; some of your suggestions as leaf no. and hairiness are practical in screening programs however you see that using root characteristics has its difficulties.

Dear Mehdi, but root system characteristics are of high importance then invaluable in such studies. The decreased evapotranspiration area and increased water absorptive root system are important morphological keys for such pre-selections.

This might be dependent on the plant type/s (big or small) and the size of screen. Soil water content and plant tissue content combined should lead to some useful data. Perhaps carry out RWC and LWC and see how well the two data sets correlate, if it is close, than you could adopt LWC over RWC as it is less time consuming. Such destructive methods will require a lot more plants (and in turn space). Leaf area measurements would give you helpful data relating to tolerance and yield but are time consuming, whilst chlorophyll fluorescence is a relatively quick and easy trait to measure. Good luck, I would be interested to hear what you opt for.

Thanks Lori for your suggestions. I agree with you using chlorophyll fluorescence or SPAD as nondestructive easy methods. however based on my current works the latter had higher correlation with seed yield under stress. RWC (in leaf) has significant correlation with seed yield in all drought treatment imposed in different phonological stages of sunflower. it appears as the most important determinant of yield under drought stress however it is time consuming.

Water use efficiency is on parameter. The second is the porometer study. Anatomical parameters to withstand stress. Finally the storage of osmotic compounds

I might suggest the following , if there are no facilities to screen the genotypes for physiological and biochemical parameters. Generally crops with the following morphometric parameters will be tolerant to drought. They are

1. Thick cuticle with waxy coating

2. Sunken stomata

3 Epidermal hairs

4. Leaves with high water retention capacity

5. Low transpirational water loss

These parameters will suffice to moderately confer drought tolerance on any genotype

Whilst sunken stomata are often claimed to be important to cope with drought or enhance water-use efficiency. I have yet to come across strong to support such a claim. Instead, there is firm evidence that sunken stomata are important to reduced the resistance for carbon dioxide diffusion in thick leaves. A few recent references include:

Hassiotou F, Evans JR, Ludwig M and Veneklaas EJ 2009 Stomatal crypts may facilitate diffusion of CO2 to adaxial mesophyll cells in thick sclerophylls. Plant Cell Environ. 32:1596-1611

Roth-Nebelsick A, Hassiotou F and Veneklaas EJ 2009 Stomatal crypts have small effects on transpiration: A numerical model analysis. Plant Physiol. 151:2018-2027

Lambers H, Colmer TD, Hassiotou F, Mitchell PM, Poot P, Shane MW and Veneklaas EJ 2014 Carbon and water relations. In Plant Life on the Sandplains in Southwest Australia, a Global Biodiversity Hotspot. Ed. H Lambers UWA Publishing, Crawley (in press, but downloadable from RG).

I would like to sugest reading the paper "Why is it so difficult to identify a single indicator of water stress in plants? A proposal for a multivariate analysis to assess emergent properties. Plant Biology 16 (2014) 578–585, 2013.

soil salinity is a high intake of minerals. if the plant support this concentration, there is no physiological damage. but in the presence of a high concentration, then there is a physiological manifestation in the plant; we talk about a phytotoxicity. simptômes begin with the yellowing of the leaf margins then browning. then the leaves fall.

this concentration of cels is generally the results exessif contribution of Fertiliser with very low agricultural irrigation soles.

Apart from what said precisely here by other scientists, the leaf color intensity could sometimes be an appropriate parameter for identifying drought-tolerant species.

Dear Mehdi,

The best rapid characteristics for screen drought tolerant cultivars are the following:

Stem water potential, RWC, LMA (leaf mass area), a rapid test for detecting drought tolerant cultivar using drop in pH of leaf extracts, DW/TW, photosynthesis, gs, transpiration, water use effiviency, chlorophyll stability index, and membrane injury. Also, morphological characteristics could be useful for detecting drought tolerant cultivars,

Best regards,