title: Introgression of cotton leaf  curl virus-resistant genes from Asiatic cotton (Gossypium arboreum) into  upland cotton (G. hirsutum).
abstract: Cotton  is under the constant threat of leaf curl virus, which is a major constraint  for successful production of cotton in the Pakistan. A total of 3338 cotton  genotypes belonging to different research stations were screened, but none were  found to be resistant against the Burewala strain of cotton leaf curl virus  (CLCuV). We explored the possibility of transferring virus-resistant genes from Gossypium arboreum (2n = 26) into G. hirsutum (2n = 52) through  conventional breeding techniques. Hybridization was done manually between an  artificial autotetraploid of G. arboreum and an allotetraploid G.  hirsutum, under field conditions. Boll shedding was controlled by  application of exogenous hormones, 50 mg/L gibberellic acid and 100 mg/L  naphthalene acetic acid. Percentage pollen viability in F(1) hybrids  was 1.90% in 2(G. arboreum) x G. hirsutum and 2.38% in G.  hirsutum x G. arboreum. Cytological studies of young buds taken from  the F(1) hybrids confirmed that they all were sterile.  Resistance against CLCuV in the F(1) hybrids  was assessed through grafting, using the hybrid plant as the scion; the stock  was a virus susceptible cotton plant, tested under field and greenhouse  conditions. All F(1) cotton hybrids showed resistance  against CLCuV, indicating that it is possible to transfer resistant genes from  the autotetraploid of the diploid donor specie G. arboreum into  allotetraploid G. hirsutum through conventional breeding, and durable  resistance against CLCuV can then be deployed in the field.
authors: Cotton Research Station, Multan, Pakistan.
authors: S
authors: S
authors: Ahmad
authors: K
authors: K
authors: Mahmood
authors: M
authors: M
authors: Hanif
authors: W
authors: W
authors: Nazeer
authors: W
authors: W
authors: Malik
authors: A
authors: A
authors: Qayyum
authors: K
authors: K
authors: Hanif
authors: A
authors: A
authors: Mahmood
authors: N
authors: N
authors: Islam
mesh_terms: D003433:Crosses, Genetic; D005838:Genotype; D003368:Gossypium / Q000235:genetics / Q000821:virology; D010154:Pakistan; D010935:Plant Diseases / Q000235:genetics / Q000821:virology; D010942:Plant Viruses; D011123:Polyploidy