Abstract:This paper deals with the genetic behaviour and breeding practice of the interspecific hybridsbetween G.hirsutum and G.arboreum obtained in 1944 and 1952.The main results are pre-sented as follows:1.The pollen grains of the Asiatic cotton germinate slowly on the stigma of the Uplandcotton.The growth of pollen tubes is slow and their female and male gametes are incom-patible at fertilization.Generally only a few ovules were fertilized within a boll.Owing tothe fact that the production of the nutritive substa...