Length of day

[AKmark]

The subject arose in another thread, so I posted a few pics of a few varieties that are tortured by our 18 hour days, soon to be 20. The pics show the south, damaged, sunny side, and the shady north side, where they look great. If I didn't know better. Yield is not affected that I can tell, my heaviest yislder last year was a tortured Caspian Pink that gave me 34lbs of fruit I don't use a shade cloth, some do up here. Has anyone done studies about this issue? Enjoy, Pruden's Purple first