Breeding, introgression and inheritance of delayed gland morphogenesis trait fromGosspium bickii into upland cotton germplasm

Abstract

A tri-specific hybrid with delayed pigment gland morphogenesis was obtained by crossing the amphidiploid of (G. arboreum X G. bickii) F1 and an upland cotton germplasm with pigment gland genotype of Gl2Gl2gl3gl3. The tri-speciflc hybrid was a typical interspecific hybrid with high sterile, and the chromosome configuration at meiosis MI of PMC was 2n = 52 = 41.04 I + 4.54 II + 0.57III + 0.04. The crossover value of bivalent was 1.19. Two fertile plants with objective character were obtained in BC8 population by continuously backcrossing with Gl2Gl2gl3gl3 as recurrent parent to the tri-specific hybrid, and a new upland cotton germplasm, named ABH-0318, with delayed pigment gland morphogenesis trait was developed through selfing and screening. The pigment gland trait of ABH-0318 was stable, and there were almost no pigment glands observed in the dormant seeds, although there were a few pigment glands confined to cotyledon edges, and the gossypol content in the dormant seeds was 0.017% only, being a typical low gossypol cotton type. However, a large quantity of pigment glands emerged in cotyledons and other main organs of plant after seed germination, and the gossypol contents in the upper parts of the plant were similar to that of ordinary glanded cotton types. Genetic analysis demonstrated that the delayed pigment gland morphogenesis trait of this germplasm was controlled by the interaction of the genes located in two pigment gland loci, Gl2and Gl3. Among them, the gene located in locus of Gl2, derived fromGbickii, was dominance to upland cotton pigment gland alleles, Gl2 and gl2, but was recessive epistatic to another glanded gene Gl3 which was named Gl2 b temporarily. While the gene located in the locus of Gl3 was a recessive gene come from upland cotton.