Optimasi Beberapa Metode Eliminasi Virus pada Apeks dan Meristem Tebu (Saccharum officinarum L.)

Abstract

Sugarcane (Saccharum officinarum L.) is the main sugar-producing plant, vegetatively propagated by using its cutting node and potentially spreading viral diseases. Mosaic disease may reduce 20-30% sugar yield. These research, performed optimization methods that can be applied for virus elimination. In this study, several methods have been optimized to support virus elimination efforts through application of hot water treatment (HWT), antiviral, and freezing on apex and meristem tissues. The objectives of this study were to know the effect of temperature and antiviral agent on the survival and regeneration rate of apexes and meristems of sugarcane PS864, to know the effect of pre-culture, loading treatment and duration of dehydration in PVS2 to the survival and regeneration rate of sugarcane apexes of PS864 after freezing in liquid nitrogen. This study consisted of five experiments: 1) the optimization of HWT (direct thermotherapy, indirect thermotherapy with and without using metal sieve filter), 2) the optimization of HWT (25, 30, 40, 50, and 60 oC) and antiviral agent ribavirin (0, 15, 20, 25 μg l-1) on apexes, 3) the optimization of HWT (25 and 50 oC) and antiviral agent ribavirin (0, 15, 20, 25 μg l-1) on meristems, 4) the optimization of dehydration treatment (0, 10, 20, 30, and 40 minute), and 5) the optimization of freezing method by vitrification technique with preculture treatment (0, 0.1, 0.3, and 0.5 M sucrose for 5 days) and loading treatment with LS solution (0, 10, 20, dan 30 minutes). The result showed that indirect HWT by using metal sieve filter was the best method. This method could decrease heat shock effect so that the apexes could grow after 50 oC treatment (25%) with regeneration rate of 4 shoots/explant. There was no interaction betwen HWT and antiviral agent. It showed that apexes could survive and grow after 50 oC (5%) or ribavirin treatment of 25 μg l-1 (57.97%) and could normally multiply on ribavirin containing media as well as their regeneration medium. However, combined treatment of HWT and antiviral agent showed no different response and interaction for survival, growth, and shoot number of meristem. Injury during isolation and high content of phenolic compound was assumed as the cause of low rate regeneration of meristem after treatment. Necrosis symptom of apexes was relatively low (< 3%) found in the ribavirin treatment of 20 and 25 μg l-1. Similar symptom did not appear on the meristem. On dehydration experiment, duration for 30 minutes was the best treatment. It was the longest periode that provide high level survival rate (74%). Post-freezing, the survival of apexes were affected by sucrose concentration on pre-culture medium. Pre-culture treatment with 0.3 M sucrose for 5 days and loading treatment for 10 minutes in LS and dehydration with PVS2 for 30 minutes was the optimal freezing method and resulted 40% survival rate.