Project Number: 2040-21000-015-07-S
Project Type: Specific Cooperative Agreement
Start Date: Sep 6, 2011
End Date: Dec 31, 2013
The objectives of this SCA are: 1) to characterize transgenic line 63-1 for its potential as papaya ringspot virus (PRSV) resistant breeding stock, and 2) to characterize hybrids from transgenic SunUp and a nontransgenic Sunrise selection with excellent appearance and shipping quality.
Objective 1. Transgenic line 63-1 is resistant to PRSV and has been deregulated in the US. Unlike line 55-1, which is the parent of the commercial Rainbow papaya, line 63-1 has two coat protein gene inserts and shows broad resistance to other strains of PRSV. Evidence from genetic crosses indicates that the two coat protein transgene inserts segregate independently. Line 63-1 will be characterized for its border sequences in order to clearly distinguish the coat protein gene inserts, and will be used as a crossing parent to broaden the resistance of transgenic lines. Objective 2. The relatively short shelf-life and speckled surface of the transgenic SunUp papaya make it difficult for Hawaii to effectively export papaya to the mainland US east coast especially. A nontransgenic Sunrise papaya selection was identified to have good shelf-life and lacked fruit blemishes. The papaya will be crossed to transgenic SunUp papaya and the progenies evaluated for PRSV resistance, good shelf life, and lack of fruit blemishes. Promising progenies will be further crossed and evaluated. Formerly 5320-21000-013-09S (05/13).