|Meredith Jr, William|
Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: August 9, 2004
Publication Date: March 1, 2005
Citation: Meredith Jr, W.R. 2005. Registration of a high fiber quality germplasm, md52ne and its recurrent parent, md90ne. Crop Science. 45(2):807-808 Interpretive Summary: The USDA-ARS at Stoneville, MS released two germplasms that are nectariless and have exceptional fiber quality. The germplasms were MD52ne and its recurrent parent, MD90ne. MD90ne is a backcross (BC4) nectariless line derived from 'Deltapine Acala 90'. MD52ne was derived by backcrossing (BC6) to MD90ne. MD52ne has 10% higher fiber strength, 22% less short fibers, and 7% longer length than MD90ne. The improved fiber quality is simply inherited making it easier for breeders to develop new varieties. Improved fiber quality is needed to make USA cotton more competitive in the world market and improve USA textile mill efficiency. The nectariless trait reduces crop losses due to the tarnished plant bug. The tarnished plant bug is currently the most destructive pest in the Delta. Seed of these two germplasms are available to researchers, geneticists, and cotton breeders.
Technical Abstract: Cotton (Gossypium hirsutum L.) germplasm MD52ne and its recurrent parent, MD90ne, were developed by the USDA-ARS, Stoneville, MS, and released in August, 2003. The two germplasms were each produced by using the backcross breeding method and using MD65-11ne in both cases as the donor parent. The first backcross program produced MD90ne. It is a BC4 line in about F8 that was produced by using 'Deltapine 90' as the recurrent parent. The donated characteristic from MD65-11ne was the nectariless (2ne1; ne2) trait. Deltapine Acala 90 is a widely grown cultivar that has been grown since 1981 and has been reported as a major cultivar since 1982 (Anonymous, 1982-2003). It possesses good yield and fiber bundle strength (T1). The yield and fiber quality of MD90ne is similar to that of Deltapine Acala 90 unless tarnished plant bugs [Lygous lineolaris (Palisot de Beauvious)] are present in large numbers. In those cases, MD90ne has produced superior yields. MD65-11ne was produced by backcrosses (BC5) to Deltapine 16ne (recurrent parent) and FTA 263-20 (GP 154, Culp and Harrel, 1980). In each segregating generation, selection was practiced for high bundle strength. 'Deltapine 16' was a popular commercial cultivar in the 1960s and 1970s and is half the parentage of Deltapine Acala 90 (Calhoun, et al. 1997). MD65-11ne's high bundle strength descends from FTA 263-20. It has a complex parentage involving Sea Island (G. barbadense L.) and Triple Hybrid [(G. arboretum L. X G. thurberi L.) X G. hirsutum]. The second backcross program produced MD52ne (BC6) by using MD90ne as the recurrent parent and MD65-11ne was the donor parent. Selection in each backcross was for high bundle strength. MD52ne has about 10% higher bundle strength, 22% less short fibers, and 7% higher mean fiber length, than its near-isoline recurrent parent, MD90ne (Meredith, 2004). The unique aspect of MD52ne is that the inheritance of improved fiber quality appears to be controlled by a small number of genes. A genetic study conducted with BC6F2:3 progenies estimated bundle strength was controlled by 1.23 (0.16=S.E.) genes (Meredith, 2004). The small number of genes conferring high fiber strength implies small numbers of progenies are needed in segregating populations to recover high fiber strength. However, as found in many fiber quality studies, yield and lint percentage are negatively correlated with high fiber strength. MD90ne is included in the release in order to provide a near-isogenic check for those wishing to study physiological-genetic associations. Small quantities of seed (100 seed) of these germplasm lines may be obtained from the corresponding author for research purposes. Recognition of the source of the germplasm is expected if it is used in the development of a new cultivar or genetic-physiological-host plant resistance studies.