Using two sweetpotato (Ipomoea batatas (L.) Lam) F1 populations from diverse environments we investigated the AFLP marker profiles of the genotypes for association studies between the molecular markers and southern root-knot nematode (Meloidogyne incognita) resistance expression. Population one consisted of 51 half-sib genotypes developed at the Louisiana State Univ. AgCenter. The second population consisted of 51 full-sibs developed by the East African and International Potato Center sweetpotato breeding programs. Results for nematode resistance expression indicate a binomial distribution among the genotypes. Using analysis of molecular variance, logistic regression and discriminant analysis, AFLP markers that are most influential with respect to the phenotypic trait expression were selected for both populations. A comparative analysis of the power of models from the two statistical models for southern root-knot nematode resistance class prediction was also done. The diversity and possible universal similarity of influential markers between the two populations and the expected impact in sweetpotato breeding programs will be discussed.
Mwamburi Mcharo*, Don Labonte, Chris Clark, and Mary Hoy
Mwamburi Mcharo, Edward Bush, Don La Bonte, Catherine Broussard, and Lowell Urbatsch
Eighteen commercial taxa in genera Liriope and Ophiopogon were evaluated genetically and morphologically. Three hundred and forty-four Amplified Fragment Length Polymorphism (AFLP) markers were identified and used in the analysis. Relatedness among taxa was estimated by analyzing the AFLP data using the Dice coefficient of similarity and UPGMA methods. The molecular analysis revealed relatively no genetic differentiation among the taxa ascribed to their respective genera, Liriope and Ophiopogon, based on morphological assessment of floral structure. Greater than 95% of the total genetic variability present was attributed to within group effects using various grouping strategies among the taxa. Among group effects were correspondingly low and not significant (P ≤ 0.05). Results suggest an indistinguishable genetic relationship may exist in the tribe Ophiopogonae between what is currently ascribed as two distinct genera.