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REGISTRATIONS OF CULTIVARS

Registration of ‘Apache’ Arrowleaf Clover

Texas Agricultural Experiment Station, Texas A&M University Agricultural Research and Extension Center, Overton, TX 75684

^* Corresponding author (g-smith{at}tamu.edu)

‘Apache’ (Reg. no. CV-216, PI 632358) arrowleaf clover (Trifolium vesiculosum Savi.) was developed through six cycles of selection for tolerance to Bean yellow mosaic virus (BYMV). Apache was identified as TX-AL98-1 during cultivar development and was released by the Texas Agricultural Experiment Station on 3 Oct. 2001. Apache is the first BYMV-tolerant arrowleaf clover cultivar.

The base population for the development of Apache had 78 half-sib arrowleaf families from a field selection program that used the arrowleaf cultivars Yuchi, Meechee, and Amclo as initial germplasm (Pemberton et al., 1989). Four cycles of restricted recurrent phenotypic selection for tolerance to BYMV were conducted under greenhouse conditions with mechanical inoculation with BYMV-KY204-1. Two additional cycles of selection were made in the field, also with mechanical inoculation with BYMV-KY204-1.

Twenty-one plants were identified in Cycle 6 that survived field BYMV infection in combination with severe root rot disease. These selections were evaluated for seed production, which ranged from none to 81 g/plant. On the basis of seed production, the best eight half-sib families were bulked and Breeder seed was produced in Oregon in 1999 with the experimental designation TX-AL98-1.

The most striking response of arrowleaf clover to infection with BYMV is a rapid, systemic wilting beginning on the youngest growth 8 to 13 d postinoculation and resulting in plant death. The inheritance of resistance to BYMV-induced lethal wilt is conferred by the recessive allele of the lethal wilt gene in arrowleaf clover (Pemberton et al., 1991). The dominant allele, L, imparting the systemic wilting response to BYMV, is present in 15 to 23% of the Yuchi arrowleaf clover population. One cycle of selection, with mechanical inoculation with BYMV-KY204-1 eliminated the susceptible (LL and Ll) genotypes (Pemberton et al., 1994).

The development of BYMV tolerance was demonstrated with arrowleaf families from four cycles of selection where four BYMV disease symptoms (dwarfing, rugosity, chlorosis, and mosaic) and dry matter production were evaluated. Level of improvement per cycle varied by component, but selection clearly improved the ability of arrowleaf clover to tolerate BYMV infection (Pemberton et al., 1994). Visual symptoms of BYMV were noted on both Yuchi and Apache in trials at Overton, TX, in 2000 and 2001.

Apache flowers 10 to14 d earlier than Yuchi and has slightly larger (18%) seed than Yuchi. Seed color of Apache ranges from yellow to red to black, and is generally darker than Yuchi seed. Apache has the same seed colors as Yuchi but with a higher percentage of black seed. Black seed occurrence in Apache is about 25% compared to about 2% in Yuchi. Flower color is white with older florets turning light pink and is identical to Yuchi.

In five trials from 2000–2001, Apache forage production was equal to Yuchi or higher (3 locations; P = 0.05). Apache was generally more (3 locations; P = 0.05) productive in early spring harvests (March–mid April) than Yuchi with forage yield increases ranging from 100% to 38%.

Foundation seed of Apache will be maintained by Texas Foundation Seed Service. Application (PVP no. 200200203) has been made for U.S. Plant Variety Protection.

NOTES

Registration by CSSA.

Accepted for publication September 30, 2003.

REFERENCES

• Pemberton, I.J., G.R. Smith, and M.R. McLaughlin. 1989. Evaluation of arrowleaf clover for tolerance to bean yellow mosaic virus. Phytopathology 79:230–234.
• Pemberton, I.J., M.R. McLaughlin, and G.R. Smith. 1991. Inheritance of resistance to virus-induced lethal wilt in arrowleaf clover. Phytopathology 81:1001–1005.
• Pemberton, I.J., M.R. McLaughlin, and G.R. Smith. 1994. Recurrent selection for tolerance to bean yellow mosaic virus in arrowleaf clover. Crop Sci. 34:1157–1163.[Abstract/Free Full Text]

This Article Full Text (PDF) Free Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Smith, G. R. Articles by Pemberton, I. J. Search for Related Content PubMed Articles by Smith, G. R. Articles by Pemberton, I. J. Agricola Articles by Smith, G. R. Articles by Pemberton, I. J.