Submitted to: HortScience
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: July 31, 1997
Publication Date: N/A
Interpretive Summary: Strawberry fruit are soft and subject to rapid deterioration, particularly from decay. In previous work involving the use of supplemental calcium fertilizers and different modes of application to strawberry plants, we found that the addition of calcium could reduce fruit decay but did not influence fruit firmness. In an attempt to see if and where the extra calcium might be going into fruit, we examined calcium and other nutrient concentrations in various parts of two strawberry cultivars, the firm-fruited 'Cardinal' and the less firm 'Fern.' Results indicated that 'Fern,' which suffers higher decay upon holding than 'Cardinal,' did not take up as much calcium. Unfortunately, most of the extra calcium that was taken into the fruit given supplemental amounts ended up in the seed and not the fleshy portion. Putting the supplemental calcium into the soil rather than spraying on the plants improved fruit uptake of calcium.
Technical Abstract: Supplemental calcium was supplied foliarly as Ca glutarate, soil incorporated as gypsum, fertigated as CaNO3, in combination, or none at all, to 'Cardinal' and 'Fern' strawberry plants grown in an Enders clayey silt loam soil (1987-1988). In 1988, individual fruits were partitioned into proximal/distal receptacle, inner/outer receptacle, and proximal/distal seeds/achenes (6 parts). Mineral nutrient concentrations (dry wt. basis) found in the inner-, outer receptacle, and seeds were, decendingly, K, P, Ca, Mg, Al, Na, Fe, Mn, Zn, B, and Cu; K, P, Ca, Mg, Na, Mn, Fe, Zn, Al, B, and Cu; and Ca, P, Mg, K, Na, Fe, Mn, Zn, Al, Cu, and B, respectively. Many nutrients tended to occur in higher concentrations in the proximal (upper) portion of the fruit compared to the distal (lower) part. Nutrient concentration gradients were lowest in the inner receptacle, with the exception of Al. Calcium was the third most abundant mineral nutrient in receptacle tissue, but most abundant in seeds. Highest fruit Ca concentrations were found (descendingly) in the seed, outer-, and inner receptacle tissue. Calcium was higher in the proximal (calyx) end. Differences between cvs in fruit Ca concentration were found in the seeds and not the receptacle tissue. The CaNO3 and combination Ca treatment were the only treatments to increase Ca fruit concentrations, and this was only in 'Cardinal' seed, not the receptacle tissue of either cv. All other nutrient concentration, except Mn, were unaffected by supplemental Ca treatments.