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a North Florida Res. and Education Center, Quincy, FL 32351
b USDA-ARS, Agronomy Dep., Univ. of Florida, Gainesville, FL 32611
c West Florida Res. and Education Center, Jay, FL
* Corresponding author (ablount{at}mail.ifas.ufl.edu)
Soybean germplasm F94-2290 Long Juvenile soybean (Reg. no. GP-281, PI 629014) [Glycine max (L.) Merr.] was developed by the University of Florida Agricultural Experiment Station. It was released 12 July 2001 as forage germplasm because of its unique long-juvenile trait, excellent seed quality, and high forage and seed yield in late plantings (i.e., after 1 July), when compared with cultivars of similar maturity (Blount et al., 2001). The long-juvenile trait refers to delayed flowering and maturity under the short-day conditions associated with late planting. Genetic analysis suggests that the trait is controlled by a single recessive gene (Ray et al., 1995). The original source of the trait is PI 159925.
F94-2290 Long Juvenile is a Maturity Group (MG) VIII line derived as a single plant selection from experimental line F91-2421. F91-2421 is an F6–derived selection from PI 417479 x F87-4039. PI 417479 is a U.S. plant introduction noted for its resistance to phomopsis seed decay [caused by Phomopsis longicolla (Hobbs)] (Berger and Minor, 1999). F87-4039 was an advanced long-juvenile selection from ‘Forrest’ x PI 159925 (Hartwig and Epps, 1973). F91-2421 was a MG VIII long-juvenile line which exhibited good seed quality, improved agronomic performance, small seed size, and segregation for plant type. Individual plants were harvested from F91-2421 in 1993 and F94-2290. Long Juvenile was selected as a progeny row in 1994 at the North Florida Research and Education Center, Quincy, FL. The selection phenotypically resembled F91-2421 and appeared uniform for agronomic traits. F94-2290 Long Juvenile was increased in 1995 at Quincy.
F94-2290 Long Juvenile was tested for seed yield in Florida and in state performance trials in Georgia in 1998 and 1999 (Day et al., 1999, 2000). When planted at the usually recommended dates for soybean (from 15 May to 15 June), F94-2290 Long Juvenile averaged 1760 kg ha-1 across 11 field trials conducted in 1998 and 1999 in Georgia and Florida, compared with a mean test yield of 2264 kg ha-1 (Day et al., 1999, 2000). In a late-planted (18 July 1997) trial at Quincy, F94-2290 yielded 2419 kg ha-1 compared with 1848 kg ha-1 for Maxcy (Shipe et al., 1995) (Blount et al., 2001). F94-2290 Long Juvenile was tested in late-planted forage trials at Quincy Florida in 1998 and 1999. Forage yield of F94-2290 Long Juvenile averaged 4235 kg h-1 compared with ‘Cobb’ (2528 kg h-1) and ‘H7550RR’ (2684 kg h-1) (USDA-ARS National Genetic Resources Program, 2002). Forage quality analysis from the 1998 study at Quincy resulted in 610 g kg-1 in vitro dry matter disappearance (IVOMD) and 140 g kg-1 crude protein (CP) values for F94-2290 Long Juvenile, compared with 620 g kg-1 IVOMD and 160 g kg-1 CP for Cobb and 640 g kg-1 IVOMD and 180 g kg-1 CP for H7550RR. All three cultivars were harvested at the same date for forage trials. Because of the delayed flowering associated with the long-juvenile trait, however, F94-2290 Long Juvenile was harvested at the R3 stage of reproductive development (Fehr and Caviness, 1977), while Cobb and H7550RR were near the R5 stage. These physiological maturity differences improved the forage quality and yield of Cobb and H7550RR because of pod and seed contribution, although total forage yield was higher for F94-2290 Long Juvenile. F94-2290 Long Juvenile averaged 720 mm in height at maturity compared with 500 mm for Cobb when planted in late July at Tifton in 1998 (James M. Woodruff, 1998, personal communication).
F94-2290 Long Juvenile is best described as a well adapted germplasm for late plantings where it has superior seed and foliage yield compared with soybean cultivars lacking the long-juvenile trait. F94-2290 Long Juvenile has MG VIII maturity, averaging 1 to 4 d later than Maxcy, when planted from mid-May to mid-June, depending on sowing date at latitudes 32° to 25°. In early to mid-July plantings at Quincy, FL, F94-2290 Long Juvenile matures 10 to 14 d later than Maxcy. It has a determinant growth habit, purple flowers, and tawny pubescence. Seed are yellow with black hila and intermediate for seed coat luster. F94-2290 Long Juvenile has good seed quality, similar to Maxcy, and is considered small seeded, averaging 14.5 g per 100 seed in early and 8.0 g per 100 seed in late-planted soybean variety performance trials in 1999 at Tifton, GA, compared with 15.2 g per 100 seed and 11.2 g per 100 seed for Maxcy (Day et al., 2000). Evaluation in regional and state testing has shown F94-2290 Long Juvenile to be moderately resistant to frogeye leafspot (caused by Cercospora sojina K. Hara), southern stem canker [caused by Diaporthe phaseolorum (Cooke & Ellis) Sacc. f. sp. meridionalis Morgan-Jones], peanut root-knot nematode [Meloidogyne arenaria (Neal) Chitwood], and resistant to southern root-knot nematode [M. incognita (Kofoid & White) Chitwood] in field tests at Quincy and Jay, FL (Blount et al., 2001).
Small quantities of seed for research and breeding purposes may be obtained from the corresponding author for at least 5 yr from the date of this publication. Recipients of the seed are asked to make appropriate recognition of the source of F94-2290 Long Juvenile if it is used in the development of a new cultivar, germplasm, parental line, or genetic stock.
NOTES
Contribution from the Florida Agric. Exp. Stn., Journal Paper no. R-08674. This research was supported by state and Hatch funds allocated to the Florida Agric. Exp. Stn. Registration by CSSA.
Accepted for publication February 28, 2003.
REFERENCES
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