| On the basis of quality determination to 192 maize inbred lines, 75 crosses were composed according to NCII design using total of 15 inbreed lines as female parent , each 3 lines ,with different protein content,derived from 5 different breeding groups of 8822, Z508, Z512, SW and M, respectively, and 5 inbreeds from five different heterotic groups as the male parent, the F1 hybrids planted in Zhengzhou and Xuchang in 2009,respectively. The contents of protein, starch, fat, lysine in kernel and crude protein, crude fat, acid detergent fibers (ADF), neutral detergent fibers (NDF) in straw were measured by NIRS (Near Infrared Spectroscopy). Meanwhile, the main ear traits and yield were evaluated and analyzed.The primary results were as follows:1) Overall, four kinds of corn grain quality traits, in addition to the performance of some starch positive heterosis, the other characters showed no positive advantages, and even some negative heterosis, but each combination of the four kinds of quality traits varied with wide ranges, and some crosses with overparent heterosis appeared, therefore, during the high-quality corn hybrid selection process, we can breed high-quality hybrid combinations with strong advantages by choosing the right parents.2) Grain quality of protein, starch and lysine content were controlled by the additive effects, additive variance (including VA and VAm) which accounted for the main effect of genetic variance (VG) of 74.05%, 65.74% and 66.67%, respectively, they suitable for selection in early generation, and oil content was mainly controlled by the cytoplasm effect, seed (endosperm) effects also have some influence, but was not affected by the maternal effect. Ear traits to the seed rate and grain weight were greater controlled by paternal additive effect and other characters were mainly controlled by the additive effect of female parent.3) Quality in straw, the crude fat and NDF were mainly controlled by genetic additive effects, genetic additive and dominance effects are all in a certain amount to ADF, crude protein was controlled by dominant effects. Breeding of high-fat and high crude protein content of hybrid, parental inbred lines must be higher general combining ability; in ADF and NDF content selection, in order to improve digestibility, while maintaining the premise of lodging-resistance, ADF, NDF content of parents should not be high general combining ability.4) Different ear traits have different heritability characters, the heritability in narrow sense of rows per ear was the highest (82.08%), followed by ear diameter (53.86%), kernels per row (51.46%) and plot yield (40.29%), while the dry ear weight ( 38.45%), ear length (36.69%), the seed rate (21.14%) as well as the axis diameter (20.40%) lower, from 20% to 39%; kernel weight in the narrow sense heritability of only 6.96%. Accordingly,on the heritability of different traits, selection in different generations in order to improve selection efficiency.5) Based on the materials in this study, although the correlation between grain yield and protein content was not significant, but still showed a positive correlation, so by genetic recombination, it is capable of breeding hybrids with high-yield and high protein content in a wide range of variation, but aggregate selection for multi-elite traitsat at the same time are much more difficult than the choice of a single character, with the marker-assisted selection technology which will greatly accelerate the pace of the fine gene pyramiding; there is no necessarily correlation between yield and straw quality, therefore, breeding hybrid with good straw quality and high grain yield is also possible.6) Combination 14×19 and 14×20 ,with not only high grain yield, but also high crude protein, crude starch content in stalk and low content of ADF and NDF, are the ideal combinations of grain and forage maize, The inbred lines( 14,19,20 )as grain and forage corn inbreeds further study is required... |
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