Summary of the OTKA grant application entitled "Studies on the genetic relationships between maize varieties based on genetic polymorphism"

OTKA Registration number: T037953

The rapid development of biochemical and molecular biological methods has led to their wide use in many fields of plant breeding, including maize breeding. Descriptions based on morphological traits are not a sufficiently reliable method for obtaining more detailed knowledge on breeding stocks or for detecting differences between lines or varieties. It is therefore essential to use techniques with which varieties can be distinguished accurately and reliably. The classification of maize varieties according to their genetic background plays an important role in breeding, since the existence of a wide genetic difference between the parental lines is a precondition for heterosis breeding. The more accurately even slight differences between the varieties can be detected, the more reliable will be the classification of maize lines into related groups. Techniques which, directly or indirectly, map the genetic background of individual plants at the molecular level provide indispensable assistance in this work.

The aim of the research described in the OTKA grant application is to identify, characterise and genetically classify maize inbred lines on the basis of morphological descriptions, isoenzyme patterns, PCR-based techniques and the heterosis test and to compare the results with those obtained using pedigree analysis. Since isoenzymes, as genetic markers, are generally suitable for the detection of differences between lines, they can be successfully used in many important fields of breeding. In some cases, however, the enzyme pattern is not sufficient to reveal differences between the lines and it is necessary to employ analysis at the DNA level, which allows the genome to be mapped with even greater precision. The genetic background of the lines can also be classified on the basis of isoenzyme patterns and in many cases the results agree with those of pedigree analysis. However, since the genes which code for isoenzymes make up only a fraction of the whole genome, some lines are not classified correctly when their origin is estimated on the basis of enzyme patterns. Again, the solution is to use methods at the DNA level, which are able to clarify the genetic background more accurately. In the course of the research the four methods mentioned above will be used to develop a system which will help to detect, on the basis of the heterosis test, which genetic markers are most suitable from the breeding point of view for the description of genotypes and which combination of marker systems allows the genetic background to be characterised with the greatest precision. It is also hoped to discover how heterosis can be predicted, thus leading to a great reduction in breeding costs.