Potato Cultivars’ Specific Leaf Weight as an Index of Response to Phosphate Limitation

Abstract

Phosphorus (P) is one of the world’s most limiting plant essential nutrients. To increase the P use efficiency during cultivar improvement, we need an effective index to evaluate the P use efficiency of each cultivar/breeding line. We conducted a field experiment using seven of the most commonly grown potato cultivars in Florida to evaluate specific leaf weight (SLW) response to P stress and adequate P growing conditions. P deficient plants generally showed reduction in leaf area and an increase in SLW. A cultivar with a smaller difference in SLW between no P vs. P amended treatments can be considered more P efficient than a cultivar with a larger difference in SLW. Among the cultivars evaluated in this study, ‘Red LaSoda’ showed the largest difference in SLW and ‘Marcy’ showed the smallest difference with and without P amended treatments. Therefore, the former represents “P sensitive” while the latter a more “P efficient” potato cultivar. Specific leaf weight may be used in controlled conditions as an index for preliminary screening of potato P use efficiency by breeding lines and commercial cultivars.