West Indies. Cotton Research Station, Trinidad. Genetics Department. Progress Report for the period October, 1942-September, 1943
Hutchinson, J.B.; Stephens, S.G.
Progress reports from experiment stations. Season, Programmes of experiments. Season 1943-1944, Emp. Cott. Gr. Corp. Lond, 168-71
1944
Document Number: 362105
Anthracnose resistance was found in a batch of (Sea Island x U.4) x U.4. back-cross material of predominantly U.4 character. It is considered that resistance could be transferred from Sea Island to Upland cottons without difficulty. Genetic work on leaf shape indicates that leaf shape modifying genes control fundamental plant processes, such as time of flowering and rate of growth, the latter having a considerable selective value on their own account.Cytological investigations are proceeding with an allotriploid (tetraploid G. arboreum x G. anomalum) with 2n = 39, and an amphidiploid (G. arboreum x G. anomalum) with 2n = 52. The amphidiploid crosses readily with New World cottons and with tetraploid G. arboreum. Hybrids have been obtained between the American diploid G. Raimondii and a series of Asiatic types carrying different leaf shape alleles. An attempt is now being made to synthesize amphi-diploids by colchicine treatment of these hybrids. If successful, the amphidiploids obtained should furnish an interesting comparison with New World cottons, and provide useful material for testing homoiogies between Asiatic and New World leaf shape alleles.