Development of PRSV-P resistant papaya genotypes by introgression of genes from wild Carica species

Date

2016

Abstract

Papaya is an important fruit commodity in the country. However, production is continuously hampered by Papaya ringspot virus (PRSV), a serious disease which resulted to low fruit quality. This project aims to further evaluate the putative PRSV-P resistant BC3 lines, BC4 lines, and F1 reconstituted 'Sinta' (new hybrid) produced from concluded ACIAR project. Field evaluation for PRSV-P resistance/susceptibility was conducted in 10 BC3 and sib-cross lines, 10 BC4 and sib-cross lines and susceptible check, Davao Solo. In general, there was variation in the rate of symptom development of BC3, sib-cross 3, BC4 and sib-cross 4 from the Davao Solo. The development of the symptoms in the backcross generations was slower than that of the Davao Solo which produced severe symptoms. There were also plants (sib-cross 3 and BC4 ) that remained symptom free from viral infection even after 11 months of exposure in the field. Furthermore, backcross plants had the ability to recover from infection and produced good and marketable fruits; in contrast to Davao Solo with few, small and unmarketable fruits. Yield trial of 17 backcross lines was also done at IPB Experimental station in Brgy. [village] Tranca, Bay, Laguna [Philippines]. A total of 108 bearing plants generated number of 2,035 fruits for six months and yielded a total of 1,036 kg. Multi-location planting of new hybrid papaya (2 lines) in three papaya growing areas (Cavite, Laguna and Institute of Plant Breeding) [Philippines] had similar response of the backcross to PRSV-P infection. Three pants of new hybrid papaya planted at IPB on 2010 remained visually symptomless after 11 months of exposure to natural infection. New hybrid plants also exhibited high tolerance against PRSV-P; wherein mild to moderately infected plant have the ability to recover from infection and bear good quality fruits. Fruit qualities of new hybrid papaya were presented. Fruits were generally sweet. The observed sweetness of the fruit could be attributed to V. querciflia since it is known for its high sugar levels. TSS ranged from vaues 11.3 to 12.30B. The fruit weight ranged from 1,412-1,628 grams and the fruits have firm yellow orange flesh with mild papaya aroma. On-station planting of 2 IPB inbred lines, 10 commercial papaya hybrids, and 4 collected germplasm was also done for extensive hybridization. Continuous selection and crossing/selfing for seed maintenance of selected backcross lines and inbred lines, population development towards red-fleshed and solo-type papaya with PRSV-P resistance/tolerance, and generation advancement of new germplasm and commercial papaya hybrids resulted to a total of 85,547 seeds. Production of new hybrid seeds was also done.

Language

English

Document Type

Article

Pages /Collation

31 leaves

En – AGROVOC descriptors

CARICA PAPAYA; PAPAYAS; HYBRIDS; GENES; INTROGRESSION; GENOTYPES; DISEASE CONTROL; PLANT DISEASES; DISEASE RESISTANCE; BREEDING METHODS; SYMPTOMS; INFECTION

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