Potential for improving freezing stress tolerance of wild potato germplasm by supplemental calcium fertilization

Abstract

The main objective of the present study was to investigate the influence of supplemental calcium fertilization on the levels of freezing tolerance in different wild potato species. For this purpose, the freezing tolerance of a broad spectrum of theSolatium taxa was evaluated with and without supplemental calcium fertilization. Previous studies have shown that there is a large variation in the calcium accumulation capabilities among species and among various accessions within species. While this study confirms such variation, no direct relationship between the leaf calcium content and the improvement in freezing tolerance was found. Nevertheless, overall 45% of the species accessions had significant higher leaf calcium content and 52% of the species accessions showed a significant drop in the frost score average at the p<0.05 level. In terms of this experiment, a drop in the frost scores meant an improvement to withstand cold. One third of the frost tolerant accessions and 41% of the frost sensitive accessions showed both, a significant increase in leaf calcium content and at the same time a significant lower average frost score. The different response observed among the accessions may suggest that even though most of the accessions are able to accumulate calcium, only some of them may have the ability to benefit from the supplemental calcium. Future breeding schemes may be able to use this information for selecting clones that would respond positively to calcium fertilization in terms of frost survival. Results of this study also suggest that calcium fertilization may be used as a rather inexpensive cultural practice for protecting potatoes from frost damage. The results of the present study also suggest that soil calcium levels should be taken into consideration when freezing tolerance of potato germplasm is being evaluated.