The use of molecular markers such as restriction fragment length polymorphisms (RFLP) gives the geneticist and breeder a new tool which has potential to ultimately characterize a breeding population, variety, or plant with laboratory analyses made with plant material from one environment. The primary objective of this study was to determine to what extent RFLP's would aid in characterizing a varieties genetic origin and as an aid in detecting parents which would produce good yield heterotic responses. A second objective was to determine if the regional origin of varieties could be used as a guide to select parents for high yielding F₂ populations. A half-diallel cross of 16 varieties was made using four varieties each from Western, Plains, Delta, and Eastern parts of the Cotton Belt. The 16 parents and 12 F, populations were grown at three locations with 4 replications in 1990. The average heterosis (F₂ -midparent) was 9% for yield. The best parents for combining high yield with high fiber strength involved crossing Delta varieties with Western Acala varieties. Wards' hierarchal clustering procedure was used to determine relationships among the 16 parents by using their agronomic and fiber quality data revealed three major clusters. The first involved the four Acala varieties and an Eastern Variety, PD 6179; the second involved the four Plains' varieties; and the third group involved the four Delta and three remaining Eastern varieties. In contrast, the same clustering procedure using 203 RFLP revealed four clusters with four varieties each. The four clusters were identical to the varieties geographic origin. The correlation between genetic diversity, using RFLP's as a measure of genetic distance, and yield heterosis was weak with n = 0.08. With this group of 203 random RFLP's there was little association between heterosis for yield and genetic distance.