On the Effect of Day-Length on the Yield of Potato.

The article deals with the dependence of the effect of the pholoperiodic treatments of potato on the length of the growing period. The results of photoperiodic treatment may differ, depending on the variety of potato, the treatment of the sets and growing conditions. The effect of long day on the tuber yield of potato has been chiefly positive. Relatively most positive effect of the long photoperiod on the tuber yield has manifested itself in some very frost-resistant clones resulting from the crosses between Solaniim tuberosum and S. demissum.