Fruit quality characteristics of Antisense ACC-oxidase Galia F1 hybrid melons (Cucumis melo L. var. Reticulatus Ser.).
Jeanmarie M. Mitchell*1, Daniel J. Cantliffe1, Harry J. Klee1, Steven A. Sargent1, Peter J. Stoffella2 1University of Florida-IFAS , Horticultural Sciences Dept., Gainesville, FL, 32611
Renowned for their flavor, Galia (Cucumis melo L. var. Reticulatus Ser.) melons have a reduced shelf-life compared to newer ‘Galia’-type cultivars, which often lack the flavor of the original ‘Galia.’ The objective of this research was to develop a true ‘Galia’ hybrid with a longer shelf-life while maintaining flavor. The ‘Galia’ male parental line was previously transformed (Nunez-Palenius et al., 2006) with an antisense ACC-oxidase gene (CMACO-1). Lines of antisense (AS) male parents were selfed and selected for the delayed ripening phenotype and a backcross 4 (AS BC4) female population was also produced. The AS T4male and AS BC4 lines were crossed (ASxWT, WTxAS, ASxAS) and AS ‘Galia’ F1 hybrid seed was produced in spring 2006. During fall 2006, AS ‘Galia’ F1 melons were grown and evaluated with the original wild-type (WT) ‘Galia’ and a ‘Galia’-type (‘MG10183’) cultivar. Fruits were harvested at four stages of growth: stage 1.) zero-slip, green (ZG); 2.) zero-slip, yellow-green (ZYG); 3.) half-slip (HS); and 4.) full-slip (FS). Data were recorded for days to harvest, fruit weight, size, flesh thickness, soluble solids content (SSC), firmness, ethylene and respiration (CO2). At stage ZG, all AS melons were similar in size, quality, ethylene and CO2 production to WT ‘Galia.’ At stage ZYG, ASxAS and ASxWT melons were significantly firmer than WT ‘Galia,’ produced less ethylene and had no difference in SSC than WT ‘Galia.’ ASxAS, WTxAS, ASxWT melons remained on the vine an average of 6, 4 and 5 days longer than WT ‘Galia and were similar in quality, ethylene and CO2 to WT ‘Galia’ at the HS and FS stages. The differences seen in lines ASxAS and ASxWT at stage ZYG indicate a potential that a longer shelf-life ‘Galia’ melon may be achieved if harvested in stage ZYG.