|Meredith Jr, William|
Submitted to: Journal of Plant Registrations
Publication Type: Germplasm Registration
Publication Acceptance Date: December 31, 2010
Publication Date: March 2, 2011
Citation: Meredith Jr, W.R., Nokes, W.S. 2011. Release notice of MD 9ne and MD25 high fiber quality cotton germplasm lines. Journal of Plant Registrations. 5(2):202-206. Interpretive Summary: To remain a viable crop competitive with synthetic fibers and international cotton competition, U.S.A. cotton needs to improve its fiber quality. The basic problem in cotton breeding for improved fiber quality is that fiber quality is negatively correlated with lint yield. The fiber traits which need to be improved are the fiber strength, length, and length uniformity. Multiple tests across nine states have shown that the two germplasms (MD 9ne and MD 25) prove to have exceptionally strong and uniform fiber. Their yields also exceed the test average of some commercial varieties. Yarn produced from these two lines have exhibited exceptional yarn strength. Stronger fibers enable textile mills to operate at higher speeds and better uniformity results in less textile mill waste. Both fiber strength and uniformity result in better quality textile products. The two germplasms descend from an ARS breeding program that has large contributions of genes from four wild cotton species. Use of these two germplasms in applied breeding programs is expected to result in improved fiber quality with no loss in cotton yields. MD 9ne is nectariless and MD 25 has reduced nectaries. These traits have been shown to reduce yield losses caused by plant bugs. Plant bugs are currently the primary cause of yield losses in the USA as well as responsible for increases in pesticide applications. Use of the nectariless trait will reduce these losses and lessen the need for insecticides. The primary users of these two germplasms will initially be cotton breeders and ultimately the cotton grower, textile industry, cotton industry and general public.
Technical Abstract: MD 9ne and MD 25 are non-commercial breeding lines of cotton (Gossypium hirsutum L.) released by the USDA-ARS at Stoneville, MS. One parent of MD 9ne was a strain of MD 51ne that had high fiber quality genes introduced from the Species Polycross. The other parent was MD 15. The parents of MD 25 are MD 9ne and a non-commercial SureGrow strain. MD 9ne was grown at eight 2004 locations in the Regional High Quality (RHQ) Test. Its yield was near average for the test. Its strength , as measured by stelometer instrument, and yarn tenacity were significantly greater than that of any other entry. Its uniformity was the highest of the 19 strains test. MD 25 was evaluated in the 2008 RHQ with 19 other entries. Yield of MD 25 was about average for the test. MD 25’s yarn tenacity was 146 mNtex-1 second to TAM 182-34ELS with 154 mNtex-1, but MD 25’s lint yield was 24.3% greater. MD25’s uniformity index and fiber length were above the test average. Removing MD 25 from a 20-entry regression analysis suggested it had a different yield-yarn tenacity relationship than the other 19 entries. MD 9ne is nectariless 2(ne1, ne2) and MD 25 is segregating for the nectariless trait. Nectariless confers resistance to a number of pests, principally the tarnished plant bug (Lygus lineolarus Palisot deBeauvois). In 2008 this insect caused as much loss in the USA as all other cotton insects combined.