Submitted to: Euphytica
Publication Type: Peer reviewed journal
Publication Acceptance Date: 7/8/2008
Publication Date: 1/1/2009
Citation: Benbouza, H., Lognay, G., Scheffler, J.A., Baudoin, J., Mergeai, G.G. 2009. Expression of the "glanded-plant and glandless-seed" trait of Australian diploid cottons in different genetic backgrounds. Euphytica. 165:211-221. Interpretive Summary: Cotton seed could be a valuable source of high quality protein; however, the seed has glands that contain detrimental compounds, such as gossypol, that limit the seed’s usefulness as food and feed. This research project developed plants (breeding lines) with seed containing less than 600 parts per million (ppm) gossypol, the limit imposed by The World Health Organisation (WHO). These breeding lines were developed using wild relatives of cotton from Australia. These relatives have plant glands, but no seed glands in contrast to cultivated cotton (Gossypium hirsutum L.) which has both plant and seed glands. Hybrids were obtained by crossing Australian cottons with cultivated cotton. Ten percent of the progeny had gossypol levels below the WHO maximum limit. These low gossypol cotton breeding lines can be used to develop varieties that produce high value feed for cows, chickens and fish.
Technical Abstract: Many Australian diploid cotton (Gossypium) species have plant glands, but no seed glands. The glands typically contain toxic terpenoid aldehyde (TA) compounds such as gossypol. The World Health Organisation (WHO) imposes a limit of 600 ppm for gossypol when cotton seed is used for flour in food and feed, and most cotton (Gossypium hirsutum L.) cultivars are currently over this limit. To evaluate the possibility of transferring the “glanded-plant and glandless-seed” trait into cultivated cotton, its expression was assessed using High Pressure Liquid Chromotography (HPLC) analysis methods in different Gossypium hybrids obtained by crossing Australian diploid cottons and various diploid and tetraploid Gossypium species. Significant variation in the gossypol content of the seed was observed among the analyzed genotypes. HPLC data demonstrated that the gossypol synthesis repression mechanism in the Australian diploid species belonging to C and G genomes was dominant but did not preferentially function against A genome species bearing GL2 (Glanding) locus. HPLC analysis of the TA content in the aerial parts of the hybrids showed important qualitative and quantitative variability. This result indicates a separation between pigment gland morphogenesis and TA synthesis mechanisms in cotton. Approximately 10 % of the produced seeds had total gossypol content lower than the limit imposed by the WHO.