Patterns of phenotypic variation in Gossypium turneri: a wild cotton with a restricted distribution in Sonora, Mexico

Abstract Crop wild relatives (CWR) represent important genetic resources for crop improvement. Gossypium turneri , a wild cotton species with a restricted distribution in the Sonoran Desert of northwestern Mexico, has been identified as a potential breeding resource for cotton improvement. While several agronomically important traits have been previously identified through limited observations from only one location within its range, phenotypic variation in this xerophytic species has not been thoroughly studied. This study aimed to describe the pattern of phenotypic variation in floral and leaf traits along the three known populations of G. turneri and identify traits of agronomic interest. Leaves and flowers through its distribution range were collected and quantitative and qualitative attributes were analyzed. Phenotypic variation in flowers and leaves was predominantly found among individuals within populations, with a smaller proportion occurring between populations, likely due to the species’ restricted distribution. Interpopulation variation in leaf traits was probably influenced by differences in local rainfall, whereas flower traits exhibited minimal interpopulation variation, likely due to similarities in pollinator composition. Some traits of interest for cotton improvement were identified, such as polymorphic bracts and production of anthers without pollen among flowers. This desert-adapted wild cotton offers valuable traits with potential for adaptation of cultivated cotton to water- and heat-stressed environments.