| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
USDA-ARS, Crop Genetics and Production Research Unit. P.O. Box 314, Jamie Whitten Delta States Research Center, Stoneville, MS 38776
* Corresponding author (wmeredith{at}ars.usda.gov)
Cotton (Gossypium hirsutum L.) germplasm MD 52ne (Reg. no. GP-787, PI 634930) and its recurrent parent MD 90ne (Reg. no. GP-788, PI 634931) 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 MD 65-11ne in both cases as the donor parent. Both MD 52ne and MD 90ne possess high fiber bundle strength combined with the nectariless trait (2ne1, ne2) and semi-smooth leaf (2t3) and offer breeders and cotton physiologists opportunities to manipulate and study a fiber property deemed essential by modern yarn manufacturing technologies.
The first backcross program produced MD 90ne. It is a BC4 line in about F8 that was produced by using ‘Deltapine Acala 90’1 as the recurrent parent and germplasm line MD 65-11ne as the donor parent. MD 65-11ne has not been officially released, but has been used in studies of canopy physiology (Wells et al., 1986) and lint trash content (Novick et al., 1991) and in breeding programs (Meredith, 1993). Deltapine Acala 90 was a widely grown cultivar until about 2001, first produced in 1981, and a major cultivar since 1982 (USDA-AMS, 1982–2003). It possesses high yield potential, good fiber bundle strength by stelometer measurement, and the semi-smooth leaf trait. The semi-smooth leaf trait results in less trash in ginned lint (Novick et al., 1991; Williford et al., 1987) and results in lower populations of the cotton aphid (Aphis gossypii Glover) compared with hirsute cottons (Weathersbee et al., 1994). The nectariless trait's yield, yield components, and fiber quality are similar to those of near isogenic nectaried cultivars unless tarnished plant bugs [Lygus lineolaris (Palisot de Beauvois)] are present in large numbers (Meredith, 1975). In those cases, cultivars possessing the nectariless trait produce similar yield components and fiber quality and result in significantly higher yields.
MD 65-11ne was produced by five backcrosses to Deltapine 16ne as the recurrent parent and FTA 263-20 as the donor parent (GP 154, Culp and Harrel, 1980). In each segregating generation, selection was practiced for high bundle strength. ‘Deltapine 16’1 was a popular commercial cultivar in the 1960s and 1970s and is half the parentage of Deltapine Acala 90 (Calhoun et al., 1997). The high bundle strength of MD 65-11ne 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 Todaro) x G. hirsutum] germplasm.
The second backcross program produced MD 52ne by using MD 90ne as the recurrent parent in five backcrosses and MD 65-11ne was the donor parent. Selection in each backcross was for high bundle strength. MD 52ne has about 10% higher bundle strength, 22% less short fibers, and 7% longer mean fiber length than its near-isoline recurrent parent MD 90ne (Meredith, 2005). The unique aspect of MD 52ne is that the inheritance of improved fiber quality appears to be controlled by a small number of genes. A genetic study conducted with BC6 F2:3 progenies estimated bundle strength was controlled by 1.23 ( ± 0.16) genes (Meredith, 2005). The small number of genes conferring high fiber strength implies small segregating populations are needed to recover high fiber strength. However, as found in many fiber quality studies, yield and lint percentage are negatively correlated with high fiber strength.
MD 90ne is included in the release 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 in genetic–physiological host plant resistance studies.
NOTES
1 Mention of trade names or commercial products in this release are solely for the purpose of providing specific information and does not imply recommendation or endorsement by the U. S. Department of Agriculture. 
Accepted for publication August 31, 2004.
REFERENCES
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| The SCI Journals | Agronomy Journal | Vadose Zone Journal | |||
| Journal of Natural Resources and Life Sciences Education |
Soil Science Society of America Journal | ||||
| Journal of Plant Registrations | Journal of Environmental Quality |
The Plant Genome | |||
