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a California Cooperative Rice Res. Foundation, Biggs, CA 95917
b Dep. of Agronomy and Range Science, Univ. of California, Davis, CA 95616
* Corresponding author (ksmckenzie{at}crrf.org)
‘L-205’ rice (Oryza sativa L.) (Reg. no. CV-113, PI 608664) is a long-grain cultivar developed by California Cooperative Rice Research Foundation, Inc. (CCRRF) at the Rice Experiment Station, Biggs, CA. It was designated experimentally 94-Y-40 and released jointly by CCRRF, California Agricultural Experiment Station, and USDA-ARS on 1 Mar. 1999.
L-205 is a pure line selection from the cross ‘M7’/R660//M7/R1588/3/82-Y-52/4/‘Rexmont’/83-Y-45 (R15679) that was made in 1989. M7 (Carnahan et al., 1978) is a semidwarf medium-grain cultivar and R660 is a sister line of ‘L-201’ (Tseng et al., 1979) developed by CCRRF. R1588 is a semidwarf long-grain selection from a cross of experimental selection 72-3761/72-32228 where 72-3761 is a selection from PI 321161, a tall, long-grain introduction from the International Rice Research Institute that was moderately resistant to cool temperature induced sterility. 72-32228 is a semidwarf long-grain selection of unknown pedigree. 82-Y-52 is a sister line of ‘L-202’ (Tseng et al., 1984), and Rexmont (Bollich et al., 1990) is a semidwarf long-grain cultivar developed by the USDA-ARS at Texas A&M University Research and Extension Center, Beaumont, TX. 83-Y-45, a parental line of ‘L-203’ (Tseng et al., 1992), is a semidwarf long-grain line having high yield potential.
L-205 is a photoperiod insensitive, early maturing, semidwarf long-grain cultivar. It has glabrous leaves and spikelets, but a few hairs occur on the lemma and palea keels. The spikelet is awnless and straw-colored with a red apiculus. The stigma is light purple. Tillers are upright with intermediate flag leaf angle and leaves are less dark green than ‘L-204’.
L-205 was compared with the commercial long-grain cultivars L-203 and L-204 in multi-location yield tests conducted in cooperation with University of California Cooperative Extension during 1994 to 1998. L-205 reaches 50 percent heading in about 88 d, which is 2 d later than L-204, and very similar to L-203. L-205 averages 91 cm in height and is about 5 and 4 cm taller than L-203 and L-204, respectively. L-205 is resistant to lodging like L-204. Visual scores for seedling vigor of L-205, L-203, and L-204 were 3.9, 4.0, and 4.2, respectively, using a scale of 1 = poor and 5 = excellent. L-205 is tolerant during the seedling stage to thiobencarb and molinate herbicides like current California rice cultivars. L-205 showed no significant difference in reaction to stem rot (caused by Sclerotium oryzae Catt.) or aggregate sheath spot [caused by Rhizoctonia oryzae-sativae (Sawada) Mordue] diseases compared with L-203 and L-204. Using a scale of 0–10 (Oster, 1990), stem rot disease ratings were 5.8, 5.3, 5.7 and aggregate sheath spot ratings (number of dead leaves on the uppermost 4 nodes) were 2.2, 2.3, and 2.2 for L-205, L-203, and L-204, respectively. L-205 is susceptible to the IG-1 race of the rice blast fungus [Pyricularia grisea (Cooke) Sacc.] that is present in California. Reaction to other blast races and rice diseases not present in California is not known.
L-205 has shown yield potential similar to L-203 and L-204. Average yield at 120g kg-1 (12%) grain moisture in the 28 tests conducted during 1994 to 1998 was 9422 kg ha-1 for L-205 compared with 9444 kg ha-1 for L-203. In 24 tests conducted during 1995 to 1998, L-205 averaged 9276 kg ha-1 compared with 9367 kg ha-1 for L-204. Whole grain milling yield from samples harvested sequentially at grain moisture contents ranging from about 220 to 150 g kg-1 (22 to 15%) over 3 years (1996 to 1998) were 584 and 570 g kg-1 (58.4 and 57.0%) for L-205 and L-204, respectively. L-205 has a smaller kernel than L-203 and L-204. In 1998, brown rice kernels of L-205 averaged 7.55 mm in length, 2.18 mm in width, and 21.7 mg in weight compared with 8.01 mm, 2.19 mm, and 24.3 mg for L-203 and 8.13 mm, 2.28 mm, and 25.9 mg for L-204, respectively. The L-205 kernel has a light brown pericarp and a colorless, non-glutinous, non-aromatic endosperm. L-205 has an apparent amylose content of 246 g kg-1 (24.6%) and an intermediate alkali spreading value of 3 to 5 in 17 g L-1 KOH solution. The apparent amylose content is about 2% higher than L-204 (22.3%) and is about the same as L-203 (25.3%). Apparent amylose content and alkali spreading values were determined by the USDA-ARS Rice Quality Laboratory, Beaumont, TX. L-205 rice cooks dry and fluffy like southern U.S. long grains. The amylographic profile of L-205 is distinctly different from L-203 and L-204, having a high set back and low breakdown which is indicative of cultivars that are well suited for parboiling, soup canning, and noodle manufacturing.
L-205 was approved for certification by the California Crop Improvement Association in 1999. The initial Foundation seed field contained glabrous medium-grain rice that appeared to be M-202 and a slightly taller bold grain type that appeared to be out-crosses with medium and short-grain rices. The off-type plants (<0.00001%) were rogued from the seed fields. Classes of seed will be Breeder, Foundation, Registered, and Certified. Application is being made for L-205 protection under the U.S. Plant Variety Protection Act, Title V Option. Breeder and Foundation seed classes of L-205 will be maintained by California Cooperative Rice Research Foundation, Inc., Rice Experiment Station, 955 Butte City Highway, P.O. Box 306, Biggs, CA 95917-0306.
NOTES
Accepted for publication May 31, 2001.
REFERENCES
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