Genetic Analysis And QTL Mapping In Tomato Cracking

Tomatoes are one of the main cultivation of vegetables, sweet and juicy its unique taste and rich nutritional value, making it a favorite. Cracking in tomato is a common physiological diseases, at the mature stage easily, Effect of storage and quality of tomato, while vulnerable to fungi, bacteria and pest infestations Fruit cracking, serious impact o n tomato yield and value of the goods. Bring huge losses to producers, tomato production is an urgent problem.Two this study, resistance to cracking significantly different parent P 1（14803） and P2（14633） as a parent, by SPSS analysis of tomato crack resistance of normal detection and correlation analysis software by P₁, F₁, P₂ carry out major gene plus polygenes inheritance of mixed model analysis of BC₁, BC₂ and F₂ 6 generations and the use of SSR and AFLP two molecular markers for traits cracks were detected construct F₂ population and QTL loci genetic map, conclusions as follows:（1）Crack index was significantly positively correlated with fruit length, fruit shape index, fruit peel shoulder toughness, tenacity peel four indicators to feed their familie s was at 0.01 level, correlation coefficients were 0.225 and instructions fruit 0.322,0.302,0.292 the longer longitudinal diameter, fruit shape larger the index, the greater the crack index. Fruit peel toughness shoulder and feed their families, the more difficult to cracking. Crack index and flesh thickness at 0.01 level was a significant negative correlation coefficient was-0.138, indicating that the flesh thicker and prone to cracking. Cracking index and fruit weight, fruit diameter, number ventricle, s oluble solids and fruit peel top toughness correlation is not significant.（2）Tomato fruit cracking traits consistent with two major gene plus- dominance- epistatic and additive- dominance multi-gene model（E-1）, to the primary additive effect based. Two major genes of tomato fruit cracking play a negative role. Seen in this combination, the additive effects of two major genes, the dominant effect and epistatic effects in tomato fruit cracking common inheritance plays an important role. BC1, BC2, F₂ heritability of major genes was respectively 83.6 %, 22.03 %, 99.22 %, 7.35 % more than was genetic, 67.56 %, was the main genetic 0, F₂ highest, significantly higher than polygenic rate. Visible, tomato fruit cracking traits acceptor genes and gene control, and the main genetic based. Indicating that the trait is the number of characters, major genes mainly by the large environmental impact, it should be selected in early generation.（3）The use of QTL Ici Mapping3.2 software for genetic mapping to obtain a tota l length of three containing SSR and 21 AFLP markers for 259.23 c M tomato cracking associated genetic linkage map, a total of three linkage groups, mark 24 sites, average map distance between loci 12.30 c M, less than 20 c M, indicating that the map that can be used for gene targeting tomato fruit cracking, development of molecular markers, molecular marker-assisted selection and cloning research important functions.（4）The use of QTL Ici-Mapping 3.2 software, a complete range of QTL mapping by mapping data on cracking F₂ population, a total of 27 check out the tomato fruit weight, fruit shape index, toughness, peel and other related QTLs, with the crack index-related QTLs detected 5, CRI-1 and CRI-2 on chromosome 1, LOD values were 2.65 and 4.90, the contribution rate of 3.68 % and 24.90 %, additive effects are negative value. CRI-3 and CRI-4 is located at chromosome 2, LOD values were greater than 2.5, the contribution rate of more than 10 %, the additive effect is positive. CRI-5 is located in chromosome 3, LOD value of 4.36, the contribution rate of 13.97 %, the distance from the flanking markers were 7 c M and 4.46 c M, additive effect was 7.04, indicating that this site comes from the male resistance to cracking on tomato cracking play an inhibitory effect.