Submitted to: Euphytica
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/15/2018
Publication Date: 9/20/2018
Citation: McCarty Jr, J.C., Deng, D.D., Jenkins, J.N., Geng, L. 2018. Genetic diversity of day-neutral converted landrace, Gossypium hirsutum L., accessions. Euphytica. 214:173. https://doi.org/10.1007/s10681-018-2264-6.
Interpretive Summary: Cotton is an important fiber crop that is grown in warmer climates through-out the world. In this study we assessed the genetic diversity and population structure of 1,115 day-neutral flowering habit conversions of landrace accessions. One-hundred-thirty-four genome wide simple sequence repeat genetic markers were used for genotyping and 192 polymorphic loci were identified. A total of 1,560 alleles were identified across the day-neutral conversions and a set of 14 US cultivars. Only 6% of the alleles were unique to the cultivars while 64% were unique to day-neutral conversions. The alleles ranged from 44 on chromosome 26 to 90 on chromosome 06. The day-neutral conversions, as a group, were not closely related. Day-neutral accessions originating in the eastern hemisphere tend to have more alleles in common with US cultivars than those originating in western hemisphere. This study identified extensive genetic diversity among day-neutral conversions which can be readily used in cotton breeding programs because of their flowering habit.
Technical Abstract: Upland cotton, Gossypium hirsutum L., is an important fiber crop that is grown in warmer climates in over seventy-five countries through-out the world and accounts for over 90% of world production. In this study we assessed the genetic diversity and population structure of 1115 day-neutral conversions of G. hirsutum L. landrace accessions (DNCA). One-hundred-thirty-four genome wide simple sequence repeat markers were used for genotyping and 192 polymorphic loci were identified. A total of 1560 alleles were identified across the DNCAs and a set of 14 US cultivars with 64% being unique to DNCAs and only 6% were unique to the cultivars. Alleles ranged from 44 on chromosome 26 to 90 on chromosome 06. The relationship matrix indicated that, as a group, the DNCAs were not closely related, and the analysis resulted in seven distinct groupings, but these were not related to the country of origin. Analysis of molecular variance revealed that most of the variation (58.3%) was due to diversity within geographic origin groups and 41.7% due to diversity among groups. Within western hemisphere or eastern hemisphere origin of collection, there is a high degree of common allele sharing, but across hemispheres, DNCAs share fewer common alleles. Accessions originating in the eastern hemisphere share 56.8-65% of alleles in common with US cultivars; whereas, accessions originating in western hemisphere share between 38 to 41% of alleles in common with US cultivars. This study identified extensive genetic diversity among DNCAs within G. hirsutum.