Mapping Quantitative Trait Loci (QTL) For Leaf Angle In Tomato

Tomato is one of Hi-light vegetable crops,the plant type has a particularly significant effect on the production of its photosynthates,which is directly related to the yield and quality of tomato.Leaf angle,as an important index of tomato geometric plant type,directly affects the distribution of light and CO₂ within the canopy and the light energy utilization of the groups,and thus affects the process of growth and physiological characteristics,and ultimately affects the yield.At present,there are few reports on the tomato plant type,and there are fewer orientations on the genes involved in the leaf angle.To study the genetic regularity of tomato leaf angle and to locate genes controlling leaf angle,it is of great significance to establish a molecular marker-assisted breeding system with the aims of improving plant type,selecting good tomato varieties and increasing tomato quality and yield.The leaf angle is a quantitative trait controlled by multiple genes and its genetic laws are complex,In this experiment,the F₂ population（172 strains）was obtained by crossing STF and TOM33,and the correlation analysis of the leaf angle traits was carried out.The genetic linkage map was constructed and the QTL for leaf angle was initially located.The experimental results are as follows:（1）Through the analysis of the data of the leaf angle between the two parents and the F₁ and F₂ generations,it was found that there was no significant difference between the leaf angles of 4th,5th and 6th node of plants.The average value of three nodes could be used for further measurement and research.The leaf angles showed a pattern of continuous variation in the segregating generation F₂,which corresponded to a normal distribution and was a typical quantitative genetic trait.（2）346 pairs of InDel primers were tested on two parents and 90 pairs of primers with good polymorphism were obtained,accounting for 26.0%.The polymorphic InDel markers were used to construct a genetic linkage map which consisted of 15 linkage groups and contained 53 markers.The total map length was 143.81cM,and the average map distance was 2.71 cM.A QTL for leaf angle was detected using the interval mapping method and located a region between the markers C10M06828 and C10M00490 at the upper end of the chromosome 10,with the genetic distances of 10 cM和15 cM,LOD value of 2.97 and genetic contribution ratio of 10.3%.（3）The two parents were re-resequenced and the InDels within the QTL region were used to design 44 new markers.Among them,12 InDel markers were found to be polymorphic between parents and 6 were further integrated into the linkage map.In the new map,the linkage group corresponding to chromosome 10 had the length of 67.33 cM and the average map distance of 6.73 cM.The QTL was allocated to the region between the markers C10M04385 and C10M00490,and the genetic distances were 6.00cM and 5.58cM,respectively...