Study On The Combining Ability And Genetic Law Of Characters Under Seedling Stage On Cucumber Under Adversity

In this research using the cucumber inbred lines(51,52,53,58,69,70) as parents, a set of diallel crosses were made according to Griffing Ⅱ to study the combining ability and genetic law of characters during seedling stage on cucumber under low temperature and low light. The following are the results:1.The difference of characters of parents and crosses during seedling stage on cucumber was significant under the conditions of 15℃/7℃(day/night)and the light of 80 μmol·m-2·s-1.2.The inheritance of the SOD activity and Pro content was mainly controlled by non-additive effect;The inheritance of the MDA content,free sugars and electric conductivity was mainly controlled by additive effect; The inheritance of the morphological characters was controlled by additive effect and non-additive effect.3.The analysis of combining ability of physiological and biochemical characters showed that the GCA effect of most physiological and biochemical characters and variance of SCA of the inbred lines(A1,A5) were high and that the SCA effect of most physiological and biochemical characters of the cross(B1)were high.The analysis of combining ability of morphological characters showed that the GCA effect of morphological characters was high,that the variance of SCA of the morphological characters of A6 was high,that the GCA effect and the variance of SCA of most morphological characters of A1 were high and that the SCA effect of most morphological characters of B1 was high.In this research the better inbred lines(A1) and the better cross(B1) were gained.4.The broad heritability of MDA content,SOD activity,free sugars,Pro content and Ec was respectively 81.17%,89.12%,55.60%,51.42%,53.66% and the narrow heritability was respectively 66.27%,0,14.35%,0和19.28%.The broad heritability of the morphological characters was above 70%;The narrow heritability of cotyledon area was 30.58% and the narrow heritability of the other morphological characters was almost 0 .5.Except the MDA content,the other characters do not accord with addition-dominance model. The additive effect of MDA content was more than dominant effect; The inheritance of MDA content was mainly controlled by additive effect, and the inheritance of MDA content was partly dominant. The dominant genes were enhancive genes.