Analysis of molecular characterizations of beets, Beta vulgaris in response to cyst nematodes, Heterodera schachtii

Abstract

Sugar beet cyst nematode Heterodera schachtii is a serious biotic limiting factor in sugar beet industry. In this study, 70 sugar beet accessions were screened against H. schachtii, of which 30 resistant and susceptible ones were subjected to polymorphic simple sequence repeat (SSR) marker analysis by seven Universal DNA Amplification (UDA) primer pairs randomly. The results showed a very high significant variation between resistant and susceptible sugar beet accessions in response to H. schachtii with 42 fold increase in nematode reproduction rate in susceptible ones. SSR primers produced 155 bands, out of which 91 ones showed polymorphism, indicating 59% genetic diversity. The highest polymorphic bands was of UDA013 primer with 17 and the lowest one in UDA010 with 10 bands. Average number of polymorphic bands per primer was 13 and per genotype 3.03 bands. The UDA015 had the highest polymorphic index content (PIC) of 80%, and the lowest 44% in UDA001 with the mean of 67%. Highest marker index (MI) was in UDA015 with 10.80, and lowest one 6.48 in UDA001, with the mean of 8.68. Cluster analysis using Numerical Taxonomy and Multivariate Analysis System (NTSYS) software, with UPGMA method based on Jacard's similarity matrix, divided the genotypes into 4 major clusters. The dendrogram was consistent with the clustering result of Principal Component Analysis (PCoA). The highest genetic similarity of 91% was between the genotypes 45 and 51, of which both were offspring of a half-brother and half-sister crossing. The results suggested novel sources of resistant to H. schachtii and that SSR marker is a reliable tool for revealing a high levels of polymorphism among the sugar beet genotypes.