When thinking of chickpeas, I thought of them as a crop which grows in hot areas. But then, I learned that there are winter varieties which survive extremely harsh winters, cold not being a problem for these varieties.
ICARDA bred some varieties which were resistant both to frost and Ascochyta blight, but I find publications on the topic only from the nineties. Where do I get seed of these varieties or breeding lines?
An example of an article found
https://acsess.onlinelibrary.wiley.com/doi/10.2134/agronj1997.00021962008900010017x
I was amazed at the cold hardiness too when I started growing them 4 years ago!
Until now i trialled about 100 accessions (mainly material from the usda and several european genebanks but some bought from seed companies too (salt spring seeds, annapolis seeds,...)).
In 2017 we grew ~50 varieties and had between -2°C and -3°C in early may when the plants were in 3-5 leaf stage. Only a few plants of one peculiar indian desi variety with green seeds died completely from the frost. Several middle-eastern and one Spanish variety had visible frost damage (but that mainly on the stipules and leaf edges in general) and i think all varieties were at least growth stunted for a few days. But all recovered and produced ripe grain.
Other years we had a few light freezes between -0,5 to -1,5°C and it was no problem at all for chickpeas in several stages of vegetative growth.
From what I've read the maximum frost tolerance in cultivated chickpea is about -5°C - and that is short term. Although we are having some freak winters in recent times where temps didn't really go below -5° I'm in central Europe and the average winter brings at least a few nights with ~-10°C. So I personally haven't tried to overwinter any. Volunteers that germinate after harvest usually die over winter but they might germinate too soon, I think most winter legumes should go into winter really small with more or less only the root established and not many nodes upper ground.
Carol Deppe mentions overwintering chickpeas in Oregon, but as far as I know the temperatures in the coastal regions there seldom drop below -2°C if it freezes long at all.
One very early mention of winter chickpeas in temperate climates can be found in the handbook for grain legume production (i don't know if that's the right translation sorry) written by Becker-Dillingen about 100 years ago. He mentions dark angular (=black desi?) forms that are grown as an overwintering crop in Hungary.
A very interesting approach would be to use wild Cicer species to cross with the cultivated crop and screen the progeny directly in regions with very harsh winters.
Cicer reticulatum (easily done) and Cicer echinospermum (harder) could be crossed with traditional hand pollination. The perennial species from Turkey etc would require at least embryo rescue to get crosses but would be in theory even more interesting! (But I think it has been tried and done successfully but with very persistent sterilities/chromosome mispairings etc.
The USDA collection holds some extremely interesting wild Cicer accessions tho, if I remember that correctly some were collected at 2000 to 2700m above sea level. I think from Turkey and Turkmenistan.
By the way, another factor that I think has to be considered here is chilling tolerance of chickpea flowers. The plan'ts won't take cold damage easily but many varieties start dropping their flowers/aborting pods when night temperatures go below ~8-10°C.
Overwintered plants might go into full bloom earlier even in temperate climates and you might loose many flowers at late cold spells. There is genetic varience for that trait as well tho, ICARDA did some work on that too i'm pretty sure.
The chickpea variety Carol Deppe bred, Hannan Popbean is by the way one variety that seems to tolerate rather low temperatures for pod set. She has also beautifully selected that variety for resistance to various soil borne diseases. I got quite some Rhizoctonia solani in my soil (always was there, as soon as I grow anything susceptible infections occur). I've seen so many chickpea varieties that get wiped out by root diseases in late seedling or early vegetative stage in some cool and wet spell in spring... while Hannan Popbean just keeps on growing and not minding the fungi.
It's of course not the only variety that is rather tolerant to those diseases and also I didn't have access to the right rhizobium strains until very recently and a good rhizobium symbiosis should add protection to infections of this kind so that should not deter people in temperate regions to try growing chickpeas!
