Identification of promising papaya (Carica papaya L.)hybrid and parental inbred lines with resistance to Papaya Ringspot Virus (PRSV).

Date

12-2011

Degree

Bachelor of Science in Agriculture

Major Course

Major in Plant Pathology

College

College of Agriculture and Food Science (CAFS)

Adviser/Committee Chair

Sta. Cruz, Filomena

Co-adviser

Magdalita, Pablito

Abstract

The PRSV infection in six papaya hybrid and inbred parental lines were evaluated under screen house conditions and were compared with the susceptible and tolerant varieties in order to identify promising lines with virus resistance. One-month old papaya seedlings of each hybrid and their parental lines were mechanically inoculated with PRSV. Resistance to PRSV was assessed based on disease onset and progress, rate of disease development, disease incidence, symptom severity and disease index. All hybrid lines tested showed delayed disease onset at 2 weeks post inoculation (wpi) which was comparable to the tolerant Cariflora (5648) but not to susceptible Solo (5647) which showed symptoms as early as 1 wpi. The hybrid line 5893 x 234 was found comparable to the tolerant control Cariflora (5648) in all parameters measured. It showed slower disease progress, slower rate of disease development, reduced symptom severity and lower disease index than Solo (5647). On the other hand, the three hybrid lines 5648 x 097, 5648 x 100 and 5649 x 234 had comparable disease progress, slower rate of disease development, reduced symptom severity except for 5648 x 100 and lower disease index than Solo (5647) but higher than Cariflora (5648). The hybrid 5648 x 100 had symptom severity similar to Solo (5647). The two hybrid lines, 5893 x 349 and 5650 x 4172 were comparable to Solo (5647) in all parameters except for disease onset. The parental inbred lines, Tainung (5893), Cavite Special (234) and C2 (5649)showed delayed disease onset, lower PRSV infection, slower disease progress and rate of disease development, reduced symptom severity and disease index comparable to Cariflora (5648). Maradol (349) was also comparable to Cariflora (5648) in all parameters used except for disease onset. Moreover, the parental lines 097 and 100 were also found to be comparable or even better than the tolerant Cariflora (5648). These two inbred lines had reduced symptom severity and lower disease index compared with Cariflora (5648).

Language

English

Location

UPLB Main Library Special Collections Section

Call Number

Thesis

Document Type

Thesis

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