In vitro and in vivo screening of potato cultivars against water stress by polyethylene glycol and potassium humate

Plantlets produced from meristem culture of four cultivars (Agria, Savalan, Satina and Caesar) propagated by single node cuttings, in May of 2008. Experimental design was factorial on the basis of completely randomized design with two factors in three replication. Factor A was plantlets of four cultivars and factor B was four treatment (One concentrations of polyethylene glycol as -1.5 bar 1L-1 MS medium, second concentrations of potassium humate (1 mL 1L MS medium) and third concentrations of PEG (-1.5 bar) with potassium humate (1 mL 1L MS medium) and other without them as control. Chlorophyll fluorescence leaves measured by chlorophyll flurometer (OS-30p) after 30 days planting. Nitrate reductase activity (NRA) measured 30 and 40 days after planting in all of organs (leaf, stem and root). Five plantlets from each cultivar cultured in a greenhouse. The highest rate of Fv/m to Caesar under normal and normal with potassium humate and Savalan stress conditions. Consequently, cultivars were ranked in order of deficit tolerance based on reductions in Fv/Fm values. Based on Fv/Fm ranking, Agria, Caesar and Savalan cultivars were identified as water deficit tolerance. Satina and Caesar cultivars had the highest rate of NRA and Savalan and Agria the lowest in all of organs. The maximum minituber average weight, number and weight per plant for was under normal with potassium humate condition. The high value of number minituber per plant were found in Savalan and Caesar under normal, normal with potassium humate and stress with potassium humate and Caesar under stress conditions. © 2009 Asian Network for Scientific Information.