Genealogy and genetic base of Brazilian cotton cultivars

Cotton is an essential worldwide commodity, and Brazil ranks fourth in world production and second in export. The present work aimed to gather the genealogies and estimate the genetic base of 109 Brazilian cotton cultivars released from 1932 to 2021. Twelve of the 68 ancestors identified contributed with 52.03% of the genes, and 33% of the cultivars resulted from the direct selection from landraces or old cultivars, evidencing a narrow genetic base. Over time, especially after 1990, the increases in the number of cultivars released and number of ancestors added to the breeding programs were driven by the need to reduce the cultivars' cycle for coexistence with pests and to make them suitable for mechanized cultivation in the new agricultural frontiers. However, Brazilian cotton cultivars still have a narrow genetic base, with the important participation of the ancestors CNPA SRI3, CKR 100W, C-77 and Express.