Molecular marker variability for southern root-knot nematode resistance in sweetpotato

Amplified fragment length polymorphism (AFLP) marker profiles for individuals in two F1 populations of sweetpotato [Ipomoea batatas (L.) Lam] were used in association studies to identify AFLP markers suitable for identification of plants possessing a resistant reaction to southern root-knot nematode race 3 [Meloidogyne incognita (Kofoid and White) Chitwood]. Population one consisted of 48 half-sib genotypes developed at the Louisiana State University (LSU) AgCenter. The second population consisted of 54 full-sibs developed by the East African and International Potato Center (CIP) sweetpotato breeding programs. Results for plant nematode resistance indicate a bimodal distribution among the genotypes for the LSU population and a normal distribution for the CIP population. Using analysis of molecular variance (AMOVA) at P < 0.001 and two multivariate analysis techniques i.e logistic regression and discriminant analysis, 5 and 4 AFLP markers that had a strong and significant association with respect to the resistance trait were selected for the LSU and CIP populations, respectively. A comparative analysis of the power of discriminant analysis models for southern root-knot nematode resistance class prediction achieved 88.78% (LSU) and 88.04% (CIP) classification efficiencies.