Identification of molecular markers associated with sweet potato resistance to sweet potato virus disease in Kenya

Abstract

Sweet potato virus disease (SPVD), a result of the co-infection of whiteXy transmitted Sweet potato chlorotic stunt virus (genus Crinivirus, family Closteroviridae) and the aphid transmitted Sweet potato feathery mottle virus (genus Potyvirus, family Potyviridae), is the most destructive disease of sweet potato in East Africa. A study was conducted to establish if genotypes identiWed as resistant or susceptible to SPVD in Kenya could be distinguished using molecular markers. A total of 47 unrelated sweet potato genotypes were selected from germplasm collections and classiWed into two phenotypic groups as resistant or susceptible to SPVD. Genotype selection was based on disease severity or days to symptom development in plants following graft inoculation.AmpliWed fragment length polymorphism (AFLP) marker proWles were generated for each individual and used in association studies to identify markers suitable for classifying the two pre-deWned phenotypic groups. Analysis of molecular variance showed signiWcant (P < 0.002) variation between the two groups using 206 polymorphic AFLP markers. Discriminant analysis and logistic regression statistical methods were used to select informative markers, and to develop models that would classify the two phenotypic groups. A training set of 30 genotypes consisting of 15 resistant and 15 susceptible were used to develop classiWcation models. The remaining 17 genotypes were used as a test set. Four markers, which gave 100% correct classiWcation of the training set and 94% correct classiWcation of the test set, were selected by both statistical methods.

Multivariate selection of AFLP markers associated with β-carotene in sweetpotatoes

“…This notwithstanding, our results suggest that both logistic regression and discriminant analysis were sufficiently robust to overcome the limitation of unequal and also small sized groups. Miano et al (2008) published results with a similar distribution. Table 1 presents the b-carotene content of the genotypes that were used in this study.…”

“…These methods, namely cluster analysis (Mcharo et al 2004), discriminant analysis and logistic regression (Uen et al 2007;Alwala et al 2008;Miano et al 2008;Du et al 2009) are also amenable to varying population structures. Our interest was to use these multivariate methods to identify molecular markers for b-carotene in sweetpotato.…”

Crop losses in Brazilian cassava varieties induced by the Cassava common mosaic virus

“…An important aspect in the evaluation of plant tolerance is knowledge of the virus genetic and pathogenic variability as it is common that plant tolerance is broken down by co-or multiple infections with different virus strains or even by highly virulent strains (Miano et al, 2008). This can make a resistant variety become susceptible in other environments.…”

Molecular characterization of sweet potato leaf curl virus (SPLCV) isolates from Korea: phylogenetic relationship and recombination analysis

“…Several begomovirus species (SPLCV, IYVV, SPLCGV, SPLCCaV, SPLCLaV, SPLCESV, SPGVaV, and SPMaV) have been reported to infect Ipomoea species and their genomes have been fully sequenced (Lotrakul et al, 1998;Banks et al, 1999;Lotrakul et al, 2003;Lozano et al, 2009;Paprotka et al, 2010). SPLCV begomoviruses have been previously isolated from sweet potato plants in the USA, Asia and Africa, and from Ipomoea indica in Europe (Lotrakul et al, 2003;Luan et al, 2007;Miano et al, 2008). Begomoviruses are likely to be present in many regions where the sweet potato is grown but knowledge about their prevalence and distribution remain elusive (Lozano et al, 2009).…”