Determination of optimum harvest maturity for five apple cultivars using the chlorophyll absorbance index

Abstract

Prediction of the optimum harvest date and storability of apples is an important concern for the fruit industry in Scandinavia. Streif index, firmness or only starch conversion are commonly used methods. To replace these with a more practical and non-destructive method, a portable spectrometer (DA meter, chlorophyll absorbance index (IAD)) was used to determine the optimum harvest date and storage potential for five apple cultivars grown in a cool climate. There was a very strong negative correlation between harvest date and IAD value in all cultivars. IAD values also showed a strong negative correlation with fruit respiration. However, the relationship was stronger in ‘Discovery’, ‘Rubinola’ and ‘Santana’ than in ‘Aroma’ and ‘Karin Schneider’. Streif index values showed very close relationships with IAD in all five apple cultivars. Apples harvested with IAD values of 0.8-1.8 had Streif index values of 0.14-0.20, which corresponds to an adequate threshold for harvesting apples for long-term storage. After four months in cold storage, fruits with higher IAD value at harvest showed higher firmness in all cultivars except ‘Rubinola’, and slower softening in ‘Aroma’, ‘Rubinola’ and ‘Santana’. Only in ‘Aroma’ and ‘Karin Schneider’ did IAD show a negative correlation, with a decline in soluble solids content during storage. Negative correlations were also found between IAD values at harvest or after storage and the occurrence of fungal decay. Since fruit respiration rate increases with advanced maturity while Streif index decreases, determination of IAD can be a very promising technique to predict the storage potential of apples and to identify high-quality fruit.

Keywords

apple (Malus domestica); chlorophyll absorbance index (IAD); Streif index; quality; respiration

Published in

Acta Horticulturae
2019, volume: 1261, pages: 219-223
Title: Proceedings of the I International Apple Symposium : Yangling, Shaanxi, China, October 10-16, 2016
Publisher: International Society for Horticultural Science

Conference

I International Apple Symposium : Yangling, Shaanxi, China, October 10-16, 2016

SLU Authors

• Tahir, Ibrahim

  • Department of Plant Breeding, Swedish University of Agricultural Sciences
    

UKÄ Subject classification

Horticulture
Agricultural Science

Publication identifier

• DOI: https://doi.org/10.17660/ActaHortic.2019.1261.32
• ISBN: 978-94-62612-58-7
• eISBN: 978-94-62612-58-7

Permanent link to this page (URI)

https://res.slu.se/id/publ/129916