Registration of ‘Spring’ Rice

‘Spring’ rice (Oryza sativa L.) (Reg. no. CV-128, PI 643121), is a very early, long-grain cultivar with blast resistance to the common races in Arkansas, developed by the University of Arkansas Division of Agriculture, Agriculture Experiment Station. Spring was released to qualified seed growers in February of 2005. It originated from the cross RU9101001//‘Tebonnet’/ ‘Katy’/3/‘LaGrue’ (cross no. 19941023), made at the Rice Research andExtensionCenter, Stuttgart,AR, in 1994.RU9101001 is an extremely early line from the cross ‘Bonnet73’/CI9837// PI265116/5/‘Vegold’/CI9556//‘Dawn’/3/‘Starbonnet’/‘Taducan’/ 4/‘L-201’. This line is extremely early and has cold tolerance during germination and early growth stages. Vegold was describedby Johnston andAdair (1965).Bonnet 73 andStarbonnet were described by Johnston et al. (1973, and 1968, respectively). PI 265116 is Zeawchanica Karatalski a very early growth duration line from Hungary which heads in approximately 48 d in Arkansas. Dawn was released by Bollich et al. (1968). Taducan is PI 280681 introduced from the Philippines. Tebonnet (Kuenzel et al., 1985) is an early high yielding cultivar, and Katy (Moldenhauer et al., 1990) is a blast resistant cultivar. LaGrue is a high yielding long-grain rice described by Moldenhauer et al. (1994). The experimental designation for early evaluation of Spring was STG97L10–118, starting with a bulk of F6 seed from the 1997 panicle row L10–118. Spring was tested in the Arkansas Rice Performance Trials (ARPT) and the Cooperative Uniform Regional Rice Nursery (URRN) during 2001–2004 as entry RU0101093 (RU number indicates Cooperative Uniform Regional Rice Nursery; 01 indicates year entered was 2001; 01 indicates Stuttgart, AR; and 093 indicates entry number). Spring is a very early maturing line that is approximately 10 d earlier than ‘Cocodrie’ (Linscombe et al., 2000). Spring has a straw strength similar to ‘Drew’ (Moldenhauer et al., 1998). Straw strength is an indicator of lodging resistance. On a relative straw strength scale (0 5 very strong straw, 9 5 very weak straw) Spring, ‘Francis’ (Moldenhauer et al., 2007b), ‘Ahrent’ (Moldenhauer et al., 2007d), ‘Wells’ (Moldenhauer et al., 2007c), LaGrue, Drew, ‘Kaybonnet’ (Gravois et al., 1995), and Cocodrie rated 4, 3, 3, 3, 3, 4, 5, and 2, respectively. Spring has an approximate plant height of 112 cm which is similar to ‘Banks’ (Moldenhauer et al., 2007a) and LaGrue. Rough rice grain yields of Spring compare favorably with those of other very short season cultivars in the ARPT. In 23 ARPT tests (2001–2004), Spring, ‘Maybelle’ (Bollich et al., 1991), ‘Jefferson’ (McClung et al., 1997), Ahrent, and Cocodrie averaged yields of 7862, 6653, 7610, 8467, and 8770 kg ha [120 g kg (12%) moisture], respectively. Data from the URRN conducted at Arkansas, Louisiana, Mississippi and Texas during 2002–2004, showed that Spring’s average grain yield of 8618 kg ha compared favorably with those of Jefferson, Francis, Ahrent (2002–2003 only) and Cocodrie, kg ha, at 8064, 9677, 8316, and 9374, respectively. Milling yields (mg g whole kernel:mg g total milled rice) at 120 mg g moisture from the ARPT (2001–2004) averaged 640:710, 610:710, 630:710, 640:690, and 670:720, for Spring, Maybelle, Jefferson, Ahrent and Cocodrie, respectively. Milling yields for the URRN (2002–2004) averaged 600:700, 610:700, 610:700, 610:680, and 620:710 for Spring, Jefferson, Francis, Ahrent, and Cocodrie, respectively. Spring, is resistant to common rice blast [Pyricularia grisea (Cooke) Sacc.] races IC-17, IE-1, IG-1, and IH-1 under Arkansas greenhouse conditions, with ratings of 3, 2, 2, and 1 respectively, using the standard disease scale of 05 immune, 95maximum disease susceptibility. Spring is MR to IB-1 with a rating of 4, and MR-S to IB-49 with a rating of 5 using the standard disease scale R 5 resistant, MR 5 moderately resistant, MS 5 moderately susceptible, S 5 susceptible and VS 5 very susceptible to disease. Like Katy, Kaybonnet, Drew and Ahrent, Spring is S to the blast races IB-33 and IE-1k, rating a 7 and 8, respectively. Spring is rated MS to sheath blight (Rhizoctonia solani Kühn) compared to Francis (MS), Ahrent (MS), Wells (MS), LaGrue (MS), Kaybonnet (MS), ‘Cypress’ (Linscombe et al., 1993) (VS) and Drew (MS). Spring is rated MS for kernel smut [Tilletia barclayana (Bref.) Sacc. & Syd. in Sacc.] compared to Francis (VS), Ahrent (MS), Wells (MR), LaGrue (VS), Kaybonnet (MS), Cypress (VS) and Drew (MS). Spring is rated S to stem rot (Sclerotium oryzae Catt.), MR to leaf smut (Entyloma oryzae Syd. & P. Syd.), MR to brown leaf spot [Cochliobolus miyabeanus (Ito & Kuribayashi in Ito) Drechs. ex Dastur], andMS to false smut [Ustilaginoidea virens (Cooke) Takah]. Spring, like LaGrue, is MS for discolored kernels caused by the rice stink bug (Oebalus pugnax). Spring is rated S to crown (black) sheath rot [Gaeumannomyces graminis (‘sacc.) Arx & D. Olivier var. graminis], and bacterial panicle blight. Spring, like ‘Cybonnet’ (Gibbons et al., 2006) is rated S to straighthead unlike Cocodrie which is rated VS. Spring should be drained on the most severe straighthead soils. Plants of Spring have erect culms, green erect leaves, and glabrous lemma, palea, and leaf blades. The lemma and palea are straw colored with straw to brown colored apiculi, and some short tip awns are present on the lemma at maturity under high fertility. Kernels are similar in size to those of Maybelle and Ahrent. In the ARPT (2001–2004) individual milled kernel weights of Spring, Maybelle, Jefferson, Ahrent, and Cocodrie, averaged 16.7, 16.6, 19.7, 16.2, and 17.9 mg, respectively. The endosperm of Spring is nonglutinous, nonaromatic, and covered by a light brown pericarp. Rice quality parameters indicate that Spring has typical southern U.S. long-grain rice cooking quality characteristics as described by Webb et al. (1985). Spring has an average apparent starch amylose content of 216 g kg and an intermediate gelatinization temperature (70758C), as indicated by an average alkali (17 g kg KOH) spreading reaction of 3 to 5. The foundation seed field of Spring was rogued several times throughout the season. The variants that may be found in the release include any combination of the following: taller, shorter, earlier, later, glabrous or pubescent plants, as well as intermediate or very long slender grains and grains with long awns. Other atypical plants may still be encountered in the cultivar. The total variants and/or off-types numbered less than 1 per 5000 plants. Application for a utility patent for this cultivar has been made to the United States patent office (Serial number 11/ 336,470; filed January 19, 2006). Breeder and foundation seed of Spring will be maintained by the University of Arkansas Division of Agriculture, Rice Research and Extension Center, 2900 Hwy 130 E., Stuttgart, AR 72160. Requests for seeds must be made to the corresponding author until 20 years from the date of patent application filing by the University of Arkansas Division of Agriculture, Agricultural Experiment Station (2006), at which time seeds will also be available from the NPGS.