DRY-MATTER PRODUCTION AND RADIATION INTERCEPTION OF POTATO

The quantification of radiation-use efficiency (RUE), the amount of dry matter produced per unit of intercepted photosynthetically active radiation, is important for yield modeling and determination of yield potentials in different environments. This study was conducted to determine the mean RUE value of potato (Solanum tuberosum L.) and its stability across diverse environments. Radiation-use efficiency was computed with growth analysis data from a field experiment with four cultivars conducted in Hawaii at four elevations, from field experimentation in Washington and Oregon, and from field experiments described in the literature for seven other locations. Radiation-use efficiency values in Hawaii varied from 2.2 g MJ-1 at 91 m elevation to 2.8 g MJ-1 at 1097 m. Genotype means in Hawaii varied from 2.2 to 2.5 g MJ-1. Comparisons across locations indicated RUE was significantly related to mean daily temperature (r2 = 0.34, n = 12, P < 0.05), vapor pressure deficit (VPD) (r2 = 0.63, n = 12, P < 0.01), and mean total solar radiation (TSR) (r2 = 0.74, n = 11, P < 0.01). Inclusion of either a VPD effect or a solar radiation effect in models of potato growth should improve dry weight predictions.