Introgression of the Glanded-Plant and Glandless-Seed Trait from Gossypium sturtianum Willis into Cultivated Upland Cotton Using Ovule Culture1
- D. W. Altman,
- David M. Stelly and
- R. J. Kohel2
Introgression of the glanded-plant/glandless-seed trait from Gossypium sturtianum Willis [2n = 2x = 26; C1 genome] into upland cotton, G. hirsutum L. [2n = 4x = 52; (AD)1 genomes] has not been successful using conventional hybridization techniques beyond the first backcross (BC1) pentaploid generation [2n = 5x = 65; genomic formula 2(AD)1C1]. Our main objective was to use ovule culture/embryo rescue to overcome this fertility barrier; secondary objectives were to determine if pairing would occur between the (AD)1 and C1 genomes and if the glanded-plant/glandless-seed trait would be expressed in other backcross generations. Pollination of BC1 plants in the field followed by ovule culture/embryo rescue produced 14 mature BC2 progeny with partial female fertility, demonstrating that tissue culture circumvented fertility barriers of the pentaploid interspecific hybrids. One BC2 had no glands while in culture, but was fully glanded after the first true leaf emerged. From this “glandless-seed” plant, eight BC3 plants |2n = 55 or 57] and 125 BC4 plants have been derived. Five BC4 seed were completely glandless. Occurrence of trivalent chromosome associations indicated C1 chromatin was transferred in the backcross generations. The average rate of AAC and/or DDC trivalent formation was 5.16% for C1 chromosomes of BC1 to BC4 plants. Germplasm derived from this material could be important for developing cotton with higher levels of insect resistance and/or improved nutritional use.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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