Cytogenetics of the 'glandless-seed and glanded-plant' trait from Gossypium sturtianum Willis introgressed into upland cotton (Gossypium hirsutum L.)

In order to introgress the ‘glandless-seed and glanded-plant’ trait from Gossypium sturtianum Willis (2n= 2x= 26, C₁ genome) into the cultivated upland cotton Gossypium hirsutum L. (2n= Ax= 52 (AD), genome), two trispecific hybrids have been created using either Gossypium thurberi Torado (2n= 2x= 26, D₁ genome) or Gossypium raimondii Ulbrich (2n= 2x= 26, D₅ genome) as bridge species. The cross of both trispecific hybrids by G. hirsutum produced the first backcross progenies (BCl). Cytogenetic analysis showed that the trispecific hybrids had 52 chromosomes, their chromosome configurations at metaphase I (Ml) being 15.071 + 15.3411 + 0.93III + 0.69IV + 0.26VI in G. thurberi×G. sturtianum×G. hirsutum (TSH) and 14.421 + 17.0311 + 0.82III + 0.15IV + 0.07VI in G. hirsutum × G. raimondii ×. G. sturtianum (HRS), respectively. Among six BCl plants analysed, the only plant expressing the ‘glandless-seed and glanded-plant’ trait had 52 chromosomes and a meiotic configuration of 5.261 + 20.61II + 0.69III + 0.77IV at MI. Pollen fertility was 2.90% in TSH, 8.97% in HRS, and ranged from 0% to 40.28% in the BCl progenies. The introgressed BCl plant is perennial in growth habit. It can be used in breeding programmes aiming at the introgression of the ‘glandless-seed and glanded-plant’ trait into a cultivar of upland cotton.