The relationship between population density of Globodera spp. with disease severity and tuber yield of potato crop

Abstract

This study was carried out to estimate the population of Globodera spp. associated with disease severity and potato yield. This research was conducted from September 2011 until January 2012 in one of the central potato plantation in Dieng Plateau, Central Java. Identification of Potato Cyst Nematoda (PCN) species using morphological character was performed by the perennial pattern method. Research was conducted using 2-stages sampling method with the first stage as altitude and second stage as disease severity. Soil and plant sampling was taken from two levels of elevation, i.e 1250-1500 m and 1750-2000 m above sea level (asl). Three locations were selected for each elevation and 3 focus for each location. Five plant with different level of disease severity were taken. Disease severity was assessed based on the plant height, degree of chlorosis, fresh weight and tuber weight per plant. PCN population were counted based on the number of cyst per 100 ml soil and the average number of eggs and juvenile’s per cyst. The increasing of NSK density has a positive correlation with the increasing of disease severities which shown by a decrease in plant height as well as fresh plant weight, and an increase in percentage of plant chlorosis. In contrary, there was a negative correlation in number of tuber produced by plant which shown by the decrease of tuber yield when there was an increase of NSK population. Population of G. pallida dominated population of G. rostochiensis at both altitudes. The prevalence levels of G. pallida to G. rostochiensis were 63% at 1250-1500 m and 70% at 1750-2000 m asl.