The Evaluation And Breeding Research Of Pitaya Germplasm Resources

In order to have a better evaluation and innovative utilization of pitaya germplasm resources, SCoT and ISSR techniques are applied In this study to analyze the genetic diversity of 36 pitaya germplasm resources, to identify and evaluate the morphology of the red, white and pink meat pitaya, and to conduct research on cutting propagation and seed germination. The main results are as follows:1.Using the improved trace CTAB method to establish suitable for pitaya germplasm resources of genomic DNA extraction method.2.Adopting the single factor and orthogonal test and establishing respectively two reaction systems which are suitable for SCoT and ISSR techniques of the pitaya germplasm resources.①SCoT-PCR amplification reaction system, the preliminary result filtered out from single factor test:template DNA 30 ng, primer concentration 0.60 μmol·L-1, dNTP 0.20 mmol·L-1,Taq polymerase 1.50 U. the best selection system of orthogonal test:DNA 30 ng,primer concentration 0.55 μmol·L-1, dNTP 0.2 mmol·L-1, Taq polymerase 2.0 U.②ISSR-PCR amplification reaction system, the preliminary result filtered out from single factor test:template DNA 30 ng, primer concentration 0.60 μmol·L-1, dNTP 0.50 mmol·L-1, Taq polymerase 2.50 U. The best selection system of orthogonal test:DNA 50 ng, primer concentration 0.55 μmol·L-1, dNTP 0.6 mmol·L-1, Taq polymerase 2.5 U.3.Establishing the program of pitaya SCoT-PCR amplification reaction:95℃pre modified 5 min; 95 ℃degeneration 40 s,50 ℃ annealing 40 s,72 ℃ extended 1 min;A total of 38 cycle; The last 72 ℃ to 10 min.4.12 primers are selected to amplify 36 pitayas by the two kinds of molecular markers. 156 amplified loci,123 polymorphic sites are obtained by ISSR-PCR amplification reaction. And the percentage of polymorphic reaches 78.85%, On average, the primers can produce 13 amplification loci and 10.25 polymorphic loci. The genetic similarity coefficient is between 0.50 to 0.91; 174 amplified loci and 141 polymorphic sites are received by SCoT-PCR amplification reaction, the percentage of polymorphic reaching 81.03%. Averagely, the primers can produce 14.5 amplification loci and 11.75 polymorphic loci. And the genetic similarity coefficient is 0.44 to 0.95. Accordingly, conclusion can be obtained from the Integrated amplification band of the two kinds of molecular markers that the genetic similarity coefficient is between 0.47 to 0.92. Therefore, At the level of genetic coefficient 0.47, cactus can be separated from the 35 Nakagoe pitaya. At the genetic coefficient 0.665,36 resources except the cactus, can be divided into two categories:21 cultivated pitayas in guangxi and 14 pitayas in Vietnam.5.Identifying, evaluating and describing morphology of the three different flesh pitaya germplasm resources.①Stem’s color of Vietnam germplasm resources is dark green, and the edge of branches is light yellow, and most of stab stem’s color is dark brown. Most of germplasm resources collected from guangxi aren’t with edge line and the stem color isn’t brown and yellow, excepting for the edge of branches with light yellow in Black King Kong.②There different flesh colors are nearly spherical three single pollen,but the length of the pollen ditch isn’t up to two ends and the surface decoration is a tumor like glyph,which composed of obvious circular particles and conical particle with nonuniform distribution.③The colors of Perianth edge of red flesh pitaya,white flesh pitaya and pink flesh pitaya are red of all,colorless and red of tip,respectively.④The meat is nearly spherical,the skin with dark purple, the scale with mostly dark purple red, and the edge of the scale is slightly brown in red flesh pitaya.The meat is ovoid,the skin with pale purple, the scale with mostly light purple red,and the scales tip and edge are green in white flesh pitaya.The meat is oval,the skin with purple,the scale with mostly green,the edge of the scale with brown, and the bud is brown on the tip in pink flesh pitaya.6.The cutting propagation of pitayas from different soil nutrition formula shows:the preparation of D processing (rural soil:coconut chaff:plant ash= 4.5:4.5:1) is the best substrate for pitaya cutting on the basis of the comprehensive analysis on the indicators such as the initial cuttings rooting, root growth, the survival rate, cuttings rooting rate, cuttings sprouting total number and the cuttings sprouting average length and so on.7.Seeds of rose flesh pitaya, pink flesh pitaya, purple flesh pitaya and white flesh pitaya are used as the experimental materials to study comparison experiments of the germination characteristics of Pitaya seeds. The results indicated that different flesh color Pitaya seeds have different germination rate, and different soaking seeds time has different germination rate. The germination rate,germination energy and vigor index of purple flesh pitaya seeds are the highest, while pink flesh pitaya seeds is the opposite.The optimal soaking time of four kinds of flesh pitaya was:Rose flesh pitaya seeds,24 h;Pink flesh pitaya seeds,36 h; Purple flesh pitaya seeds,36 h; White flesh pitaya seeds,36 h.