Use of mineral element content of potato petioles for predicting yield potential

Six potato clones (Kennebec, Norchip, Norland, Red Pontiac, Russet Burbank, and M6664) were grown in a split-plot designed experiment to study the relationship of tuber yield and the mineral element content of petioles, both measured at 14 day intervals during the growing season. Seasonal trends in the N, P, K, and Mg content in petioles were highly intercorrelated. Concentrations of N, P, and K decreased with time, while Mg increased. Clones differed in the rate of change in these elements during growth. Trends in N, P, K and Mg content in petioles were highly correlated with tuber bulking. Change in N, P, K, and Mg concentrations are hypothesized to be a function of the sink strength of developing tubers. For another set of potato clones grown in a replicated yield trial, the change in petiolar K content with time was the “best” variable associated with final tuber yields. A regression model [Model II: Y(cwt/A)=200.6223-1887.0150 (b_k)] is given for predicting the yield potential of 18 clones. Given the slope of the petiolar K concentration (b_k) during growth, this model identified 9 of the 10 top yielding clones. Factors affecting the reliability of the model are discussed.