Registration of MD 9ne and MD 25 High‐Fiber‐Quality Germplasm Lines of Cotton

Abstract

MD 9ne (Reg. No. GP‐928, PI 659507) and MD 25 (Reg. No. GP‐929, PI 659508) are noncommercial breeding lines of cotton (Gossypium hirsutum L.) released by the USDA‐ARS at Stoneville, MS. One parent of MD 9ne was a strain of ‘MD51ne’ (PI 566941) that had high‐fiber‐quality genes introduced from the species polycross. The other parent was MD 15 (PI 642769). The parents of MD 25 were MD 9ne and a noncommercial Sure‐Grow strain. MD 9ne was grown at eight locations in the 2004 Regional High Quality (RHQ) test. Its yield was near average for the test. Its strength as measured by a stelometer instrument and it yarn tenacity were significantly greater than those of any other entry. Its uniformity was the highest of the 19 strains tested. MD 25 was evaluated in the 2008 RHQ test with 19 other entries. The yield of MD 25 was about average for the test. MD 25's yarn tenacity was 146 mN tex−1, second to TAM 182–34ELS with 154 mN tex−1, but MD 25's lint yield was 24.3% greater. MD 25's uniformity index and fiber length were above the test average. Removing MD 25 from a 20‐entry regression analysis suggested that it had a different yield/yarn‐tenacity relationship than the other 19 entries. MD 9ne is nectariless 2(ne1 , ne2 ), and MD 25 segregates for the nectariless trait, which confers resistance to a number of pests, principally the tarnished plant bug (Lygus lineolarus Palisot deBeauvois). In 2008 this insect caused as much loss to the cotton crop in the United States as all other cotton insects combined.