An attempt was made to determine the processing quality and optimum processing maturity of 10 potato cultivars grown under short days and analysed at different stages of growth beginning from 60 to 90 days after planting (DAP). Yield, specific gravity, dry matter and starch content of tubers increased up to 90 DAP. Chip colour also improved at 90 DAP, while reducing sugars, sucrose and total sugars showed an increase up to 70 DAP and declined afterwards. Soluble protein content of the tubers increased significantly up to 80 DAP, while the free amino acids were maximum on 60 DAP. Phenolic compounds showed no definite trend during growth, although orthodihydroxy and total phenols were minimum at 90 DAP. The results suggested that minimum level of reducing sugars in the tubers in conjunction with optimum specific gravity, dry matter content and tuber yield should be considered as the basis for determining optimum maturity of potatoes for chipping. Taking into account these factors, tubers of Kufri Chandramukhi, Kufri, Tyoti and EMC/1021 attained optimum processing maturity at 80 DAP, while Kufri Bahar, Kufri Lauvkar, Gulmarg Special, A 2235, JC 3046, JC 6415 and SLB/Z 569 achieved this at 90 DAP. Kufri Lauvkar and A 2235 were found to be most suitable for processing into chips, while 3 potato cultivars, viz. Kufri, Tyoti, EMC/1021 and SLB/Z 569 were considered ideal for canning. JC 3046 and JC 6415 were most suited for the production of starch and manufacture of dehydrated processed products.
