Natural variation in fruit abscission-related traits in apple (Malus)

• Published in: Euphytica Vol. 165; no. 1; pp. 55 - 67
• Main Authors: Sun, Lingxia, John Bukovac, M, Forsline, Philip L, van Nocker, Steven
• Format: Journal Article
• Language: English
• Published: Dordrecht Dordrecht : Springer Netherlands 2009; Springer Netherlands; Springer; Springer Nature B.V
• Subjects: Abscission; Agricultural production; Agronomy. Soil science and plant productions; Apples; Biological and medical sciences; Biomedical and Life Sciences; Biotechnology; Cultivars; ethylene production; fruit drop; Fruits; fruits (plant anatomy); Fundamental and applied biological sciences. Psychology; Genetics; Genetics and breeding of economic plants; Hybrids; Life Sciences; Malus; Malus domestica; pedicel; Plant Genetics and Genomics; Plant Pathology; Plant Physiology; Plant reproduction; Plant Sciences; ripening; Seed dispersal; Transgenic plants; wild relatives; Fruit ripening; Ethylene; Abscission; Natural diversity; Fruit; Rosaceae; Woody plant; Ripening; Apple; Dicotyledones; Angiospermae; Genetic improvement; Spermatophyta; Malus
• ISSN: 0014-2336; 1573-5060
• DOI: 10.1007/s10681-008-9754-x

Abscission or retention of ripening fruit is a major component of seed dispersal strategies and also has important implications for horticultural production. Abscission-related traits have generally not been targeted in breeding efforts, and their genetic bases remain mostly unknown. We evaluated 144 Malus accessions representing wild species, domestic cultivars, and hybrids for abscission-related traits. We found that seasonal timing of fruit abscission in wild species and hybrids showed a broad distribution similar to that seen for domestic cultivars, and that internal ethylene concentration at the time of abscission varied by over three orders of magnitude. Wild species, domestic cultivars, and hybrids all included representatives that showed abscission of fruit prior to substantial production of ethylene, as well as accessions that retained fruit for a significant period of time following ethylene production. For all accessions that retained fruit, fruit removal resulted in abscission of the pedicel, and exogenous ethylene promoted abscission, suggesting that the abscission zone was functional. Our results suggest important roles for mechanisms independent of fruit ethylene production in abscission.