Genetic Analysis Of Embryonic Callus Induction And Plant Regeneration From Immature Embryo Culture In Maize

Twenty-one maize inbred lines commonly used in practice were taken as experiment al materials and six ones were selected as parents to build the six-parent diallel cross. B eing cultured with immature embryo, all inbred lines and crosses were investigated on t he frequency of embryonic callus induction and the number of regenerating plant. After doing research on difference of the genotype, on effect of combining ability (CA) , on heredity pattern and heredity effect, genetic action of immature embryo culture in maize plant resources was explored. It provided the base for selecting materials as genet ic transformation acceptors in maize. Results are followed.1. Variance analysis showed genotype was the main factor affecting both embryonic callus induction and plant regeneration of immature embryo culture in maize inbred line and cross.2. The same rule was concluded on both embryonic callus induction and plant rege neration. Crosses presented high values if both parents behaved high. Crosses presented 1 ow values if both parents behaved low. Parents with low value being hybridized by thosewith high values, the values of crosses distributed widely. Most of them increased com paring to low value parent to a certain extent. Such distribution and increase in the desce ndants indicated that both traits were quantitative trait and could be transferred after hybr idizing. With advantageous genes introduced in, traits behaving bad formerly would be i mproved. So at least one parent must be good in order to achieve the good cross for eith er trait.3. The result of correlation analysis showed that the correlation coefficient between frequency of embryonic callus induction and number of regenerating plant in inbred lines was tested not to be significant. It meant that the two different traits were determined by different heredity factors. On the contrary, such correlation coefficient in crosses was tested to besignificant. Using the crosses to build transgenetic acceptors, we need not to testify both traits but to reason one trait with the other directly. Then the process of acceptors selection would be simpler.4. Correlation analysis showed that frequency of embryonic callus induction and number of regenerating plant were separately significantly correlated to its general combining ability(GCA) in inbred line. Frequency of embryonic callus induction and number of regenerating plant were also separately significantly correlated to its special combining ability (SCA) in cross. On the basis of such significance of correlation, parent would be selected just according to either the value of GCA or the value of parent itself as well as cross could be selected just according to either the value of SCA or the value of cross itself.5. Genes controlling the induction and regeneration lied in cell nucleus. So the mode of hybridize had no influence on the efficiency of culture.6. Additive-dominance genetic pattern was found to be functional to induction. The additive effect accounted for 98.60%. Dominant effect was between partial dominant effect and complete dominant effect and was close to the latter. Meanwhile, both values o f broad heredity and narrow heredity reached more than sixty percent. Consequently, ai m of selection for induction should be decided to get homogametic varieties. Process of selecting should be put up among upper generations by individual plant strictly and that GCA was preferential to SCA.7. As for regeneration, additive effect accounted for 75.60%. Dominant effect contr ibuted to non-additive effect but epistatic effect did not. Link genes might exist. Both va lues of broad heredity and narrow heredity were just about forty percent. Consequently, heterosis should be used in early generations as well as homogametic varieties should bedeveloped in late generations. Both GCA and SCA should be taken into account in the process of selection for parents.8. There were several recessive genes that led the embryonic callus induction to b e...