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ARS Home » Northeast Area » Geneva, New York » Plant Genetic Resources Unit (PGRU) » Research » Publications at this Location » Publication #226568

Title: Natural Variation in Fruit Abscission-Related Traits in Apple (Malus)

Author
item SU, LINGXIA
item BUKOVAC, M
item Forsline, Philip
item VAN NOCKER, STEVE

Submitted to: Euphytica
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/16/2008
Publication Date: 6/30/2008
Citation: Su, L., Bukovac, M.J., Forsline, P.L., Van Nocker, S. 2008. Natural Variation in Fruit Abscission-Related Traits in Apple (Malus). Euphytica.

Interpretive Summary: Abscission or adherence of ripening fruit is a major component of seed dispersal strategies and also has important implications for horticultural production. Traits related to timing of fruit drop have generally not been targeted in breeding efforts, and their genetic bases remain mostly unknown. We evaluated natural variation for seasonal timing of fruit abscission, as well as the timing of fruit abscission in relation to ethylene production, in 144 Malus accessions representing wild species, domestic cultivars, and hybrids, in order to better characterize this trait. 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.

Technical Abstract: 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.