Expanding Resistance of Papaya Ringspot Virus to Improve Papaya Cultivars for Hawaii and the Us Market
Tropical Plant Genetic Resources and Disease Research
Project Number: 2040-21000-015-17
Start Date: Nov 22, 2013
End Date: Dec 31, 2015
Papaya is one of the most commonly eaten fruits worldwide especially in areas around the tropics. In the United States, people who emigrated from these tropical regions enjoy the imported papaya fruits in the markets throughout the country. Hawaii has the only commercial papaya plant that is resistant to papaya ringspot virus (PRSV) in the United States. The transgene responsible for resistance to the Hawaiian PRSV also confers resistance to PRSV strains from countries such as Mexico. Here we propose to incorporate the PRSV resistance to different cultivars of papaya such as the Maradol papaya that is a favorite for the Hispanic population and test these against the various PRSV papayas. We will also continue to select for lines with improved shelf life and appearance for the Hawaii papaya markets.
SunUp papaya which is homozygous for the transgene conferring resistance to the PRSV will be crossed with Maradol papayas. The resulting F1 progeny will be selfed and backcrossed to Maradol to provide both the quality and taste characteristics of Maradol. Molecular analysis will be conducted to ensure both copies of the transgene are also incorporated into the papaya selections to ensure PRSV resistance. Maradol x SunUp progeny will be sent to Cornell University to be screened against various strains of PRSV to confirm the resistance. Both conventional seed propagated lines and elite lines with favorable traits may be propagated by tissue culture for field testing. In addition, we will continue to select for lines with improved shelf life and quality for the Hawaii market.