Study on seed transmission of piper yellow mottle virus (PYMoV) in three varieties of black pepper

Piper yellow mottle virus (PYMoV) is the dominant virus causing mottle disease in black pepper plants (Piper nigrum) and is reported as a seed-transmitted virus. The study was conducted to confirm the seed transmission rate of PYMoV in three black pepper varieties, namely Petaling-1, Natar-1, and Ciinten. Three hundred seeds from ripe berries for each variety were grown on cocopeat media. The seedlings with a pair of true leaves were transferred to soil+fertilizer media in the greenhouse. Seedlings grown from fallen seeds under the mother plant (voluntary seedlings) were collected from plantations in Sukabumi. Observation of disease incidence and PYMoV detection by PCR was carried out on grown and voluntary seedlings. The mottle and chlorotic symptoms on the leaves of the grown seedlings began to appear 10 weeks after germination. In voluntary seedlings, the same disease symptoms were found on leaves. The disease incidence and the PYMoV frequency in grown and voluntary seedlings of Petaling-1 and Ciinten ranged from 2.53–21.00% and 2.00– 14.00%, respectively. PYMoV was detected in both symptomatic and asymptomatic grown seedlings and only in symptomatic voluntary seedlings. Infection of PYMoV was not found in Natar-1, but there were seedlings with viral disease symptoms, indicating another viral infection. PYMoV occurrence in voluntary seedlings suggests its potential as a source of disease inoculum in the field. Screening healthy plants as a material to increase genetic diversity through seeds and removing voluntary seedlings is one of the strategies to control the spread of disease.