QTL Analysis Of Several Rice Agronomic Characters

Many agronomic traits in rice such.as heading date(HD), plant height(PH), panicle characters (Grain length, Grain width, et al.) are quantitative traits. Which vary continuously and are controlled by polygenes. We call them quantitative trait locus(QTL). It has played a very important role in improving agronomic traits, gene tagging and cloning, molecular marker assisted selection and increasing yield to study QTL.In this study,176 F2 and 126 Recombinant Inbred Lines(RIL)populations was applied to construct genetic linkage map, which derived from the cross between Shennong 265 and Lijiangxintuanheigu was used to detect QTLs. The main result indicates that:1. The objective of this study was to identify QTLs conditioning rice heading date using a F2 polulation,4 QTLs for heading date on chromosome 2,chromosome 3,chromosome 6 and chromosome 7 were identified, These putative QTLs were located on chromosomes 2,3,6,7 respectively. The percentage of phenotypic variations explained by these QTLs ranged from9.7% to 23.0%.6 QTLs Which control the heading date have ever been fine mapped in their linkages:qHD2 as Hd7, qHD3-1 as Hd9, qHD3-2 as Hd8, qHD3-3 as Hd6, qHD6-1 as Hd3, qHD7 as GHd7(Hd4) respectively. A new QTLs:qHD6-2 which have never be detected (http://www.gramene.org/db/qtl/).2. The objective of this study was to identify QTLs conditioning rice mesocoty length using a RIL polulation of 126 individuals, a linkage map consisting of 121 markers was constructed, which convered all of 12 chromosomes in rice. The total length of the map was 1397.50 centimorgan (cM), The average linkage distance was 15.61 cM.5 QTLs for panicle length on chromosome1, chromosome2, chromosome3, chromosome6 and chromosome 11 respectively were identified. The LOD value of each QTL was ranged from 3.65 to 15.52.The proportions of phenotypic variance explained by individual QTL ranged 7%-33%, qML3, qML6 and qMLll were detected in two conditions, qMLl and qML2 were only detected in water.3. Identified 13 QTLs for grain characters on chromosome2, chromosome3, chromosome8, chromosome9, chromosome10, chromosome11 and chromosome12 were identified respectively.5 QTLs for grain length are detected,4 QTLs for grain width and 1000-grains weight wera detected, The phenotypic variations (VE) explained by individual QTL were ranged from 13.2% to 55.8%.4.43 QTLs for panicle characters were identified.5 QTLs for primary branch number, spikelet number of primary branch, spike let number of secondary branch are detected respectively,4 QTLs for panicle length, spikelet number of primary branch, pikelet number per secondary branch and percent seed set are detected,3 QTLs for secondary branch number, percent seed set of secondary branch were detected, spikelet number per panicle, grain number per panicle and percent seed set of primary branch were detected 2 QTLs respectively.The proportions of phenotypic variance explained by individual QTL ranged 12.9%-46.38%.5. Detected 22 QTLs for plant height and interval length on chromosome1, chromosome2, chromosome3, chromosome5, chromosome6, chromosome7, chromosome8, chromosome9, chromosome11 and chromosome12 were identified respectively.5 QTLs for plant height and 17 QTLs for interval length(3 QTLs for I interval length from top,6 QTLs for II interval length from top,4 QTLs for II and IV interval length from top respectively) were detected.The phenotypic variations (VE) explained by individual QTL were ranged from 2.54% to 50.79%.