L. C. Marton

Studies on the adaptability of maize hybrids under various ecological conditions

The adaptability of twelve single cross maize hybrids was investigated at five different locations in Hungary over a three-year period. The characters examined were individual plant production (total mass of the ears on a single plant), thousand kernel mass, number of kernel rows, ear length, number of kernels per row, shelling % and the assimilating leaf area above the main ear.Among these yield components, the individual plant production, the ear length, the number of kernels per row and the grain-cob ratio (shelling %) were influenced to the greatest extent by the year, followed by the variety and the location. The greatest average yield was achieved by the tested hybrids at all five locations in 1997 (263 g/plant). The average yields in 1998 and 1999 were significantly lower (221 and 203 g/plant, respectively). The outstanding yields achieved in 1997 could be attributed to the favourable ecological conditions, which led to the development of secondary ears in Keszthely and Sopronhorpacs. At the other ...

Applicability of biochemical and genetic markers In the polymorphism analysis of maize lines

The guidelines elaborated by the Community Plant Variety Office (CPVO) of the European Union for the registration and patenting of varieties and hybrids of cultivated crops are based on the triple criteria of distinctiveness, uniformity and stability (DUS). For many species, however, morphological descriptions are not sufficient for the detection of differences between varieties. Techniques that allow varieties to be identified and distinguished precisely and reliably are essential not only for variety identification, but also to protect variety ownership rights. Biochemical and molecular genetic methods have now reached a level of development that makes them suitable for this purpose, and when these are combined with conventional field observations the breeding stock can be unequivocally identified and any existing genetic diversity can be detected. The regular application of such analyses is a fundamental criterion in the case of maize, as more and more closely related hybrids are being entered for test...

The use of morphological traits and genetic markers to estimate genetic relationships in maize

The use of genetic markers allows the study of polymorphism and genetic distances between maize lines in greater depth than can be achieved on the basis of phenotype and DUS traits. The analysis of polymorphism between 46 maize inbred lines with known genetic background and the classification of these lines in related groups was carried out by means of morphological description, isoenzyme analysis, RAPD analysis, and identification using gene-linked microsatellite (SSR) markers. The genetic distance or degree of relationship between the lines was determined using cluster analysis. Only a very limited extent of allele polymorphism could be detected in isoenzyme analyses; the 46 lines formed only 18 gel electrophoresis groups. Nevertheless, on the basis of RAPD and SSR markers, all the lines could be distinguished from each other. This was reflected by the PIC (polymorphism index content) values, which ranged from 0.04 to 0.55 (mean 0.27) for the various enzyme loci, while far higher values were obtained for RAPD and SSR markers (0.20–0.91, mean 0.61, and 0.54–0.90, mean 0.73, respectively). Due to the large number of lines, two lines, derived from each other or from common parents, were chosen from each related group as the basis for grouping the lines according to genetic background. It was found that, while the individual marker systems only partially reflected the actual relationships between the lines, a joint processing of the genetic markers, supplemented with morphological data, revealed a close correlation between the groups formed on the dendrogram and the genetic background.