ARS | Publication request: MASSIVE PREFERENTIAL SEGREGATIONS AND NONRANDOM ASSORTMENT OF LINKAGE-GROUPS PRODUCE QUASI-LINKAGE IN AN F2 MAPPING POPULATION OF WATERMELON

Submitted to: HortScience
Publication Type: Abstract Only
Publication Acceptance Date: November 17, 2003
Publication Date: October 15, 2003
Citation: Levi, A., Thomas, C.E., Newman, M.L., Zhang, X., Xu, Y., Wehner, T. 2003. Massive preferential segregations and nonrandom assortment of linkage-groups produce quasi-linkage in an F2 mapping population of watermelon. [abstract]Hortscience. 181:782

Technical Abstract: Three populations were used to develop a comparative linkage map for watermelon (Citrullus lanatus). They include a BC1 population {[Citrullus lanatus var. citroides PI 296341 x C. lanatus var. lanatus cv. New Hampshire Midget (NHM)], x NHM}, a testcross population (TC)[(C. lanatus var. citroides germplasm line Griffin 14113 x NHM) x C. colocynthis PI 386015], and an F2 population (PI 296341 x NHM). Common markers allowed the merging of linkage groups from the three maps, and confirmed consistent distances among markers within linkage groups. However, in contrast with the BC1 and the TC populations, the F2 population displayed nonrandom assortment against several PI 296341 linkage groups. Major linkage groups that are distinct in the BC1 and TC populations could be readily merged using common markers. However, in the F2 population nonhomologous linkage groups merged into one giant linkage group producing Quasi-Linkage. This linkage anomaly may be a result of strong affinity between nonhomologous chromosomes, causing them to pass to the same pole during cell division. This anaomaly will likely be prevalent in F2 populations derived from crosses between watermelon cultivars and C. lanatus var. citroides.