Qi Ren Chu | 6/14/2005 5:56:41 PM
Yield component studies had focused on two main school of thoughts, namely ‘super rice’ and “ideal rice.” A preliminary study in 2002 at the LSU AgCenter’s Rice Research Station indicated that the U.S. commercial varieties of long-grain rice are mainly composed of two plant types. Louisiana types (Cocodrie, Cypress and Cheniere) have multiple tillers with intermediate panicle size, while Arkansas types (Francis, LaGrue, Wells) possess a larger panicle size but moderate tillers per plant. Current developed doubled haploid (DH) lines are characterized to be in between the two U.S. types. This study aims to identify and compare the performance of major yield components of DH lines influencing yield under irrigated conditions.
Twenty-three genotypes (five commercial varieties and 18 lines) were planted in a randomized complete block design with three replications during the 2003 main season. Data including plant height, panicle length, number of productive tillers/yard2, number of grains/panicle, percent filled grains, and 1000-grain weight were randomly recorded from a randomly placed quadrate area in each plot. Yield and vegetative vigor were recorded from the gross plot area (4.9 x 1.4 m). Data were analyzed through SAS PROC ANOVA, and means were compared by Duncan’s Multiple Range Test (DMRT).
Results indicated there were significant (P≤0.05) differences in all the traits among the genotypes. Highest yield performances obtained from DH lines 004372/00447277 and CCDR/98LL0401 were due to possession of relatively high % filling ability, a fairly well setting of total number of spikelets/panicle and in 1000-grain weight as compared with commercial varieties. Also, line CCDR/98LL0401 demonstrated a good performance in number of tillers/yard2 in addition to the other above mentioned traits. Although most entries were within the acceptable levels of plant height range (79-97 cm) and seedling vigor ratings (3-5) some falling within this group exhibited lodging incidences, including the variety Wells. This suggests that improvement on lodging resistance is required to minimize field grain yield losses and quality deterioration. It thus reflects that development of DH lines have appreciable improvement on total number of spikelets/panicle, 1000-grain weight, and tillers/yard2 as compared with commercial varieties. Lines 0043752/0047277 and CCDR/98LL0401, which are characterized with average vigor and resistant to lodging, are the elite lines with highest yielding ability as a result of constantly maintaining relatively high levels in total number of spikelets/panicle, % filled grains and 1000 grains than the rest of the tested materials.Comparison of Yield Components of 18 Long-Grain Doubled Haploid Lines