Abstract
Effects of time of infection of banana bunchy top virus on susceptibility of three banana cultivars. Banana Bunchy Top, caused by Banana Bunchy Top Virus (BBTV), is one of the most important banana diseases in Indonesia. Approach to reduce disease incidence involves prevention of early infection especially on susceptible cultivars. This study was conducted to evaluate the response of three banana cultivars, Ambon Kuning, Tanduk, and Kepok, to different time of infection of BBTV i.e., one week and three week after adaptation period, and one week during adaptation period. Banana plants used in the study were prepared through in vitro propagation (tissue culture) and virus transmission was done using aphid vector, Pentalonia nigronervosa. In addition to observation on symptom expression, inhibition of plant height, and reduction of leaf size, conformation of virus infection was done through indirect ELISA. Virus concentration on different part of the plant, young leaf, stem, and root, tends to decrease over the time due to the ability of BBTV to move from cell to cell before replication takes place. It is evidenced that BBTV was able to infect banana in all growth stages although the younger plant is more susceptible to BBTV. Although concentration of the virus in the tested plant is considered high, symptoms expression of BBTV infection can be differentiated from moderate to very severe. Response of banana plants to infection of BBTV can be grouped into susceptible (Ambon Kuning), moderate tolerant (Tanduk), and tolerant (Kepok).