The paper presented here have introduced the principles and characteristics of several QTL(Quantitative trait locus) analysis methods in plant, including the single-marker QTL analysis, the interval mapping and the composite interval mapping. The single-marker QTL analysis is based on the sub-groups of marker genotypes to do the significance analysis of average values and the one-way analysis of variance. The interval mapping is used to estimate the probability of having QTL at any position in the interval between any two adjacent markers. The composite interval mapping has been developed on the basis of the interval mapping with use of multiple regression model in the ma- ximum likelihood estimate, and thus may give high accuracy and power in mapping QTLs due to the control over large number of background genetic variation in studying population. Especially in mapping QTLs with epistatic effects and QE interaction, some extensive ways of the composite interval mapping can produce more reliable
PEG macromonomer having one methacryloyl end group for per polymer chain was selected as reaction stabilizer. The distribution of molecular weight of the macromonomer was less than 1.1 based on the GPC analysis. Poly(acrylonitrile/styrene) particles with sub-micron sizes were prepared by dispersion copolymerization of acrylonitrile with styrene by using 2,2-azobisisobutyronitrile(AIBN) as a free radical initiator in the presence of PEG macromonomer in V(ethanol)∶V(water)=7∶3 mixed solvents at 60 ℃ for 24 h. The particles having narrow size-distribution were obtained and studied by transmission electron microscopy(TEM) and laser light scattering(LLS). The surfaces of the particles have unusual structures(strawberry form or wheel form shows) which can be control by changing molecular weight of PEG macromonomer and other reaction conditions. The structure of the freeze-dried particles was investigated by X-ray diffraction(XRD) system and showed a distinct diffraction peak at 2θ=22.6°, indicating that the particles are crystallized.
