Construct A Linkage Map Of Rice And Single Segment Substitution Lines Using ILP Marker

Most traits of crop are quantitative, which are controlled by polygenes. Finely mapping of quantitative trait loci (QTLs) is very important for crop genetic improvement. Single segment substitution lines (SSSL) containing only one segment of donor chromosome introgressed into a recipient genetic background can be used for QTL fine mapping and map-based cloning. The present research has developed a SSSL population that was in an elite genetic background of Nipponbare introgressed from 93-11 by using backcross and Intron Length Polymorphisms (ILP) marker-assisted selection. The main results are as follows:1. A linkage map comprising 173 ILP markers and 12 SSR markers was constructed based on the Nipponbare/93-11// Nipponbare BC₁F₁ population consisting of 102 plants. The map covers 1905.70cM in total length with an average distance of 10.30cM between adjacent markers. Among these ILP and SSR markers, 30 markers (16.22%) showed the genetic segregation distortion (P<0.05). There are 28 (93.33%) distorted markers deviated toward dornor parent 93-11, only 2 markers deviated toward recipient parent Nipponbare.2. One hundred and eight overlapping single segment substitution lines with the Nipponbare genetic background have been developed, which include 54 different substituted segments distributed on chromosomes 1-11 excluding chromosome 12. More single segments are on chromosomes 1, 2, 3, 6, the numbers are 7,8,9 and 8 respectively.3. The length of the 54 single substituted segments ranges from 3～121.2cM, covering 2046.5cM in total length with an average length 37.90cM. Among them, 38 single segments is less than 50cM in length. After Getting rid of the overlapping, the overall length of the 54 single substituted segments is 1173.5cM, and its coverage of the rice genome is 61.58% . Highest coverage(100%) were on chromosome 8,10 respectively. Lower coverage(39.43%, 36.48% and 37.16%) were on chromosome 4,5 and 11 respectively.This paper studies on the method of constructing a marker linkage map useing ILP marker and developing SSSL using ILP marker- assisted selection, which provides base for the study and the use of SSSL to identify and finely map QTL in the future.