Density-increasing Of Genetic Map And QTL For Hybrid Population Of Populus Adenopoda×P.Alba

In this paper, Based on 132 individuals derived from Populus adenopoda×P. alba F1 family and two-way pseudo-test cross mapping strategy, SSR and SRAP markers were used to enhance the density of the P. adenopoda and P. alba genetic maps which were constructed by Wang(2008). QTLs of leaf and growth quantitative traits were located on the new maps. This research has important theoretical and practical significances for genetic breeding of poplar.Four hundred and sixty-one new polymorphic loci including 23 SSRs and 438 SRAPs were obtained. Among them 139 (including 7 SSRs and 132 SRAPs) were added to the map of P. adenopoda, and 150 (including 6 SSRs and 144 SRAPs) were added to the map of P. alba.236 markers were available on the P. adenopoda map, including 98 SSRs and 138 SRAPs containing 92 SSRs and 6 SRAPs of the original map. The map was 2956.7cM long and contained 24 linkage groups (respectively composed of 4 to 26 markers), with an average length of 123.20cM, ranging from 10.7 to 256.3cM. The average distance between adjacent markers was 13.95cM (The original is 20.60cM). The map for the paternal P. alba. tree genome was costructed with 263 markers (including 109 SSRs and 154 SRAPs and containing 103 SSRs and 10 SRAPs of the original map). The map had total length of 3199.6cM, composed of 27 linkage groups (respectively containing 4 to 27 markers), with an average length of 114.28cM ranging from 7.2 to 350.3cM. The length of marker intervals was on average 13.62cM (The original is 19.26cM). The genome size of the female tree P. adenopoda was estimated at 2996.55cM, and genome coverage was estimated to be 91.36%; The genome size of the paternal tree P. alba.was estimated at 3217.78cM, and genome coverage was estimated to be 89.21%.By means of composite interval mapping, at LOD=2.5, QTLs of 11 traits (including the leaf area, leaf circumference, leaf length, leaf width, petiole length, ratio of length to width of leaf, the hair on the back of the leaves, height, diameter at breast height, diameter at ground height, number of sprouts) have been analyzed and located on the new maps. Totally 39 different QTLs were identified. QTLs mapped explained from 6.82% to 25.4% of phenotypic trait variance.