Diversity of Primitive Upland Cotton Germplasm
Feb 8, 2019
Improvement of crop species requires genetic resources that may extend from primitive or exotic species to commonly grown cultivars. The introduction of desirable traits from germplasm sources to adapted cultivars is an ongoing process. The cotton, Gossypium hirsutum L., collection of primitive accessions contains a wealth of genetic variability; however, many of the accessions are photoperiodic. The photoperiod response and failure to flower and set fruit under the long-day regime of the temperate-zone growing seasons is a major hurdle in utilising most primitive cotton germplasm. A programme was initiated several years ago convert primitive accessions to day neutrality by incorporating day-neutral genes utilising a backcross breeding approach. Useful genetic variability has been measured in the day-neutral lines for resistance to Heliothis spp., Pectinophora gossypiella (Saund.), Anthonomus grandis Boheman, Meloidogyne incognita (Kofoid and White) Chitwood, and for agronomic and fiber traits. The day-neutral accessions are now available for use in breeding programs for cultivar development and to expand genetic variability.