|Meredith Jr, William|
Submitted to: Journal of Plant Registrations
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: January 2, 2013
Publication Date: May 10, 2013
Citation: Meredith Jr, W.R. 2013. Registration of MD25-26ne, MD25-27, and MD25-87 germplasm lines of cotton with superior yield, fiber quality, and pest resistance. Journal of Plant Registrations. 7:1-7. Interpretive Summary: Cotton breeders have long desired to produce new varieties that had both increased yield and fiber quality. Fiber quality is the combined interaction of micronaire (fiber maturity), length, uniformity, and strength. These fiber traits result in improved operations of textile mills, better quality textiles and improve cotton’s competitive ability with man-made fibers. The problem with improving both yield and fiber quality is as breeders improve yield, fiber quality decreases or as fiber quality increases, yield decreases. MD25 is a released germplasm that has both good yield and excellent fiber quality. MD25 showed signs of having considerable genetic variability among the various plants from which it was derived. For example, some plants have nectaries and some are nectariless. In 2008, random plants were individually harvested and grown as progeny rows in tests at Stoneville. Three lines that repeatedly showed high yields and fiber quality were selected for extensive off-station testing. The three proposed germplasm lines were designated at MD25-26ne, MD25-27, and MD25-87. Testing in two major regional tests showed that the yield of the three selections was equal to or greater than commercial varieties. Their fiber properties were superior to that of commercial varieties. Other tests showed that the three selected MD25 progenies had resistance to root knot nematodes and tarnished plant bugs; in the USA, these are the most damaging pest disease and insect in cotton. Use of these germplasm lines should lead to new varieties with higher yields, excellent fiber quality, and pest resistance.
Technical Abstract: Three non-commercial cotton (Gossypium hirsutum L.) lines which were released by the USDA-ARS are MD25-26ne (PI 666042), MD25-27 (PI 666043), and MD25-87 (PI 666044). The three lines are reselections out of MD25 (Reg. No GP-929; PI 659505). The objective of this research was to select lines that had better combinations of yield and fiber quality than MD25. Starting with 153 F3 random MD25 selections, reductions and reselections were made in 2009, 2010, and 2011 which resulted in these three MD lines being retained. The 2010 and 2011 strains tests from multiple environments showed the selected MD25s had average yields of 1517 and 1363 kg/ha, respectively. In 2011, in the eight Regional High Quality (RHQ) Tests, the average yield of the three selected MD25s and 12 transgenic cultivars was 1276 and 1295 kg/ha, respectively and their average yarn tenacity was 135 and 117 mNtex-1, respectively. In 2011, average yield over 13 locations in the Regional Breeders Testing Network (RBTN) for the three MD25s and three test checks was 1487 and 1413 kg/ha, respectively. RBTN fiber quality score (QS1) average for the three selections and the three RBTN check cultivars was 78.7 and 52.2, respectively. None of the other 24 test entries exceeded the average of the three MD 25 lines. For the second fiber quality score (QS2), the rank of the three entries was 1, 2, and 4. Average QS2 for the three MD25s and three check cultivars was 81.2 and 67.5, respectively. In other RBTN and RHQ tests, the three selected MD25 lines showed resistance to tarnished plant bugs. The three MD25s also indicated good resistance to root-knot nematode. The combination of high yield, fiber quality, and pest resistance make these three lines useful for further cotton improvement.