Mapping wound-response genes involved in post-harvest physiological deterioration (PPD) of cassava (Manihot esculenta Crantz)

Abstract

The genome locations of the wound-response genes that were expressedduring the post-harvest physiological deterioration (PPD) of cassava, suchas phenylalanine ammonia lyase, ?-1.3 glucanase, hydroxyprolinerich glycoprotein, catalase, 1-aminocyclopropane 1-carboxylate, cysteineprotease inhibitor, aspartic protease, a partial cDNA for serine/threonineprotein kinase and peroxidase, have been identified on the frameworkmolecular genetic map of cassava. Also, molecular markers linked toputative quantitative trait loci (QTLs) influencing PPD of cassava weremapped using an F1mapping population derived from elite parentallines (TMS 30572 × cm 2177-2). A molecular linkage map previouslyconstructed based on the segregation of 240 RFLP, 100 RAPD, 85microsatellite and five isoenzyme markers on 144 F1 individuals wasused for the QTL mapping.A set of 10 molecular markers with a significant association with putativeQTLs for PPD were identified based on probability values < 0.005in order to minimize the detection of false positives. Based on single-markerregression, eight putative QTLs located on the linkage groups G, P, L, U,and X of the female-derived framework map were found to explain between 5 12% of the phenotypic variance of the PPD. In the male-derived frameworkmap, two putative QTLs on linkage groups C and L explained 13% and11% of this variance, respectively. This study thus identified the majorgenome regions of cassava related to physiological post-harvestdeterioration, thereby providing tools for the identification of gene(s)controlling this trait.