Adaptability, stability, and productivity of potato breeding clones and cultivars at high latitudes in Europe

Abstract The aim of potato breeding is to release cultivars showing high and stable performance across the target population of environments. The objective of this research was therefore to investigate the use of various methods (site-regression [SREG], coefficient of variation and the regression’s deviations [σ2δ]) for determining adaptability and stability for productive and quality traits in the Nordic Region of Europe. The multi-environment trials included 256 breeding clones and released cultivars grown by EU farmers at three distinct testing sites over two years in Sweden. There was significant (P < 0.001) variation for tuber yield, starch percentage and reducing sugars in the tuber flesh among breeding clones and cultivars, testing environments and their GEI. The environments were very diverse as revealed by SREG biplots and particularly for the GEI patterns noted in productive and quality characteristics. The percentage of stable high-tuber yielding germplasm was larger for breeding clones (23%) than for the European released cultivars (2%), thus showing the advantage of potato breeding in the target population of environments. SLU 1415001 and SLU 1314015 were the most promising breeding clones due to their stable high tuber yield. The starch potato cultivars were the best for this characteristic, although none of them had a non-significant σ2δ. ‘Talent’ shows an almost stable good performance among low reducing sugar cultivars and breeding clones, which were often unstable in their scoring across environments. Neither a breeding clone nor a cultivar was at the top ranking for stable tuber yield, tuber flesh starch and reducing sugars in the tuber flesh, which shows the challenge faced by potato breeding while addressing the need of different markets.