LSU AgCenter Releases Two New Rice Varieties for 2012

Steven Linscombe  |  2/17/2012 10:28:17 PM

Della-2

Mermentau

The LSU AgCenter has released two new rice varieties for production in 2012. Both of these varieties are the result of a number of years of breeding research at the Rice Research Station near Crowley. Della-2 (experimental designation LA2140) is the latest aromatic specialty rice variety to be developed at the station. It was developed by pedigree selection from a three-way cross Cypress//(L-205/Della)F1 in the winter of 2001. The aromatic parent Della is a tall, lodging-susceptible variety with a very low yield potential, which was released by the LSU AgCenter 38 years ago for certain domestic consumers who prefer a fluffy long-grain cooking texture yet a strong popcorn-like aroma. Several semidwarf Della-type varieties – including Dellrose, Dellmont and A-301 – were released in the early- to mid-1990s. However, they lacked Della’s superior grain quality and aroma characteristics and also lagged in yield potential to current conventional varieties. A concerted effort to improve Della’s agronomic characteristics while maintaining its superior quality led to the release of Della-2.

Della-2 is a short-stature, moderately early-maturing, Della-type, aromatic long-grain experimental rice variety with very good grain yield, good milling yields and excellent grain quality. Della-2 averaged 40 inches in height in yield tests across Louisiana compared with 36 inches for Chenier and 39 inches for Dellrose. It has moderately early maturity similar to both Cheniere and Dellrose. The average number of days from emergence to 50 percent heading is 87, 86 and 87 for Della-2, Cheniere and Dellrose, respectively. In 16 head-to-head yield comparisons between Della-2 and Dellrose, Della-2 outyielded Dellrose in 13 of those trials. Della-2 is moderately susceptible to rice sheath blight, bacterial panicle blight and straighthead disorder but moderately resistant to blast.

Both Della-2 and Dellrose have a similar broad flag leaf; however, the flag leaf of Della-2 is longer than that of Dellrose. The leaves, lemma, and palea of Della-2 are glabrous. The spikelet is straw-colored. The apiculus color is light green at heading and straw-colored at maturity. The grain is aromatic.

Della-2 has the typical Della-type cooking quality with intermediate amylose content, intermediate gelatinization temperature and very strong aroma. The average amylose content of Della-2 is 21.8%, compared with 24% for Cheniere and 23.1% for Dellrose. The average alkali spread value of Della-2, Cheniere and Dellrose is 4.1, 4.7, and 3.8, respectively. The average 2-acetyl-pyroline (2-AP) content of Della-2 is 678 ng g-1, which is significantly higher than the 582 ng g-1of Dellrose. The measurement of 2-AP is indicative of the relative strength of the aromatic characteristic of a rice variety. The milled rice of Della-2 is longer, more slender and more translucent than that of Dellrose and Della.

Mermentau (experimental designation LA2085) is a semidwarf, early-maturing long-grain rice variety with good grain and milling yields and excellent grain quality. It was developed using the pedigree selection method and was selected from the cross AR1188/Cocodrie//9502088/LaGrue that was made at the Rice Research Station in 2001. AR1188 is a long-grain experimental line developed in Arkansas, while Cocodrie is a very early long-grain semidwarf variety developed at the Rice Station. The experimental long-grain breeding line, 9502008, was developed at the Rice Station, while LaGrue is a conventional height long-grain variety developed in Arkansas. Mermentau originated as a bulk of a single progeny row in 2005. It was evaluated in the preliminary yield nursery in Crowley, La., in the summer of 2006 with the experimental designation 06PY732 before being entered into the Cooperative Uniform Regional Rice Nurseries in 2007 with the designation RU072085.

Mermentau has averaged slightly higher yield levels than Cheniere and Catahoula over four years of multi-location testing. While head rice yields are comparable for the three varieties, Mermentau has slightly longer and more uniform grain length as well as lower chalk levels in most growing environments. Mermentau averaged 36-37 inches in height in yield tests across Louisiana, which is the same height as Cheniere and Catahoula. The three varieties are also very similar in maturity with Mermentau averaging the same number of days to 50 percent heading as Cheniere and one day earlier than Catahoula.

The leaves, lemma and palea of Mermentau are glabrous. The spikelet is straw-colored. The apiculus color is purple at heading and fades slightly as the grain approaches maturity. The grain is nonaromatic. Mermentau has typical long-grain cooking quality with intermediate amylose content and intermediate gelatinization temperature. Mermentau is susceptible to rice sheath blight and bacterial panicle blight and moderately susceptible to straighthead disorder and blast.

Limited amounts of foundation seed of Della-2 and Mermentau may be available from the Rice Research Station. More information may be obtained by contacting Steve Linscombe.

Permission granted Feb. 15, 2012 by B. Leonards (LA Farm & Ranch) to republish article on www.lsuagcenter.com.

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