Genetic Analysis Of Main Traits And Establishment Of Regeneration System Of Peach

In this research, main traits of peach (Prunus persica (L.) Batsch) have been analyzed based on practice of crossing breeding. Density-increasing of Peach Genetic Map by SSR Technique and the traits of flesh were located on the map, the regeneration system of leaves and hypocotyl were optimized and the factors involved in the regeneration of leaves and somatic embryo were investigated. The results made a stable basis for better selection of breeding parents, decreasing breeding procedure, increasing breeding efficiency and the convenience for transgenic breeding. The results were as follows:1. The heredity analysis of main traits in peach.The heredity of fruit qualitative traits, maturity, fruit size, flower type and pollen compatibility traits in peach were studied, the result showed that hairy and nectarine, round and flat fruit, white and yellow flesh, melt and non-melt texture were controlled by a isolate qualitative locus, the former was completely over the later respectively.The heredity of maturity date showed the characters of quantative traits, and appeared central tendency, but did not appear the typical normal distribution. Using late maturity×early maturity,the maturity date of the hybridized progenies showed two distribution peak in the early or late of two parents, it illuminated that the trait of fruit mature date of peach is controlled by the major gene loci; The variation coefficient of progenies was 7.1～26.8, the transmission force of average combination was 97.2%, the estimation value of narrow sense heritability was 0.83, the character of fruit mature period has high heritability; Breeding value and trait heritability of two cultivars with early maturity,'76-2-12'and'hu 005', were higher than other varieties, so they could be used as ideal parents with early maturity traits in peach breeding.Fruit size was controlled by quantitative character of multiple genes, showed the tendency of smaller fruit size in progenies, the variation coefficient of 25 combinations was 14.3～42.5, the value was 25.3, the extent of variation was high, it showed clearly transgressive inheritance; The large fruit parents didn't appear additive effect, breeding value and trait heritability of fruit size were lower, the fruit size of progenies tend to small size especially, and its average heritability of all combination and narrow heritability were 72.8% and 0.16, respectively. Cultivars including'4-33','75-5-10'and'Qinguang No.2'have higher breeding value and trait heritability, so they could used as ideal parents with large size fruit in peach breeding.The peach flower pattern and pollen fertility were controlled by singe gene, for example the bell-shaped flower for rose-shaped flower was inadequacy dominant, the pollen fertility for sterility was absolutely dominant; The flower diameter of two parents or single parent was smaller than 3.2 cm, the flower diameter of most of its hybrid progenies were smaller than 3.2 cm, the flower diameter of hybrid progenies of other type flower appeared separate between 3.7cm and 4.7cm.This paper also analyzed the genotype of other qualitative character about parents.2. Density-increasing of Peach Genetic Map by SSR TechniqueSSR markers were used to increase density of the peach (Pruns persica (L.)Batsch) AFLP genetic map based on a 91 F1 progenies derived from the cross of Prunus persica cv.'Qinguang No.2'and'Shuguang'. The main results as follows:53 Polymorphism loci were selected from 57 pairs of SSR primers with rich and steady bands were tested in F1 separate progeny, of which 19 markers were skewed segregation(P<0.01).A molecular genetic linkage map was increased in locus using SSR marker, there were 15 SSR markers were integrated in linkage group 2, 3, 4, 5 and 7, the fruit early maturity character was located in linkage group 5.There were no significant changes in the constrcture of the peach linkage map with AFLP markers after density-increasing using SSR markers but the lengths of density-increased linkage groups and the positions of a few markers. After density-increased by SSR, the linkage gaps more than 20 cM disappeared in the linkage group 5 and 7, and the average length of linkage group decreased to 8.08 cM.3. Establishment of peach regeneration systemThe cotyledons, hypocotyls and leaves of early-ripen nectarine varieties'Huaguang','Shuguang'and tao varieties'Qinmi','Shahong', were cultured in order to study the factors affecting their regeneration, the results showed:In cotyledon regeneration, the best sampling phase of'Huaguang'was 60 days after blossom and the regeneration rate of the cotyledons was 75% when they were cultured with the medium MS+TDZ 2 mg/L+NAA 0.04 mg/L. The best time sampling cotyledons of'Shuguang'for regeneration was 60 days after blossom and the regeneration rate was 50% cultured by medium MS+BA 8mg/L+NAA 0.04mg/L.'Qinmi'for regeneration was 70 days after blossom and the regeneration rate was 31.25% cultured by medium MS+TDZ 2.0mg/L+NAA 0.04mg/L.'Shahong'for regeneration was 77 days after blossom and the regeneration rate was 60.42% cultured by medium MS+TDZ 2.0mg/L+NAA 0.04mg/L.In hypocotyl regeneration, no remarkable regeneration difference between upper and lower hypocotyls was found. The QL medium combining with TDZ 2.0mg/L, and NAA 0.04mg/L was the best for Huaguang's hypocotyls regeneration. The MS medium combining with BA 3.0mg/L and NAA 0.04mg/L was the best for Qinmi's hypocotyls regeneration.In leaf regeneration, several factors such as the variety , plant hormone, lesf position and so on were investigated to optimize the regeneration system in vitro. The vertical cut leaf with near axial surface touched the medium LP+2.0mg/l BA+0.2mg/l NAA cultured in dark for 21d then transferred on LP+6.0 mg/l BA +0.2mg/l NAA medium and cultured at 24~28℃and 1500-2000 Lx get better callus and more somatic callus, then about 8.33% adventurous buds for'Huaguang'.