The researchers analyzed genetic distance and heterosis in early maturing upland cotton parent lines to help select cross parents and predict hybrid vigor. They divided 12 parent lines into two groups and found a correlation between genetic distance and heterosis in certain traits of the offspring. The genetic distance between parent lines was related to the heterosis of traits like boll weight and yield, with some traits showing positive correlations and others showing negative correlations. Overall, early maturing upland cotton showed higher heterosis in boll weight and yield, while genetic distance was not directly linked to overall yield.