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Notes: Summary The proteins of the seed flour of 26 X-ray induced mutants and 5 recombinants of the species Pisum sativum were analysed quantitatively and qualitatively. The values obtained were related to the seed yield of the genotypes In this way, the protein yield as well as the production of specific amino acids per genotype were determined. The following results were obtained. 1. The mean values for the character “total protein content of the seed flour” of the genotypes studied varied between 14 and 23%. The fasciated mutant 489C produced 18–23% more seed proteins than the initial line in three subsequent generations. The mean values of some other mutants and recombinants were 10–17% higher, the lowest value being 27% lower than that of the control values. In the material investigated there is no correlation between seed size and seed protein content. 2. The buffer-soluble seed proteins of 55 mutants were electrophoretically subdivided in different subfractions and the protein patterns were determined. They are extraordinarily variable. Distinct groups of mutants do not only differ from the initial line but also from one another with regard to the number, position and breadth of their bands. A correlation between the degree of morphological deviations of specific genotypes and the composition of their seed proteins was not observed. Moreover, differences in the concentration of specific protein fractions between the genotypes were densitometrically ascertained. 3. The globulins and albumins of some genotypes were quantitatively determined and electrophoretically subdivided into subfractions which differ between different mutants with regard to their number as well as their concentration. This is especially valid for the albumins which could be essentially stronger subdivided than the globulins. 4. The amino acid spectra of all the mutants investigated agree qualitatively with the spectrum of the initial line, however, clear quantitative differences in distinct amino acids were observed. The proportion of the essential amino acids is increased in two mutants by 5 and 20% in relation to the control line. 5. The protein production of the fasciated mutant 489C was 20–70% higher than the corresponding values of the initial line in three subsequent generations regarding its high seed production. The protein yield of the early flowering mutant 46C was about 20% lower and that of the bifurcated mutant 1201A 12–31% higher as related to the initial line. Mutant 1201A shows an equally favourable situation with regard to the total content of the essential amino acids. Its lysine production exceeded the control values by 20–40%. 6. The different components of the protein synthesis can negatively be influenced by the co-operation of the mutant genes. The protein production per plant, the total production of essential amino acids as well as the lysine production are lower in the recombinants 68C/176A and 68C/1201A as compared to the parental mutants. The combination of genes 68C and 46C does not show any negative interactions.

Notes: Summary The germination of the pollen grains and the growth rate of the pollen tubes of eight mutants of Pisum sativum were compared with the parent line by in vitro investigations. All of the mutants studied showed a retardation of pollen tube growth as compared to the parent line, resulting in competitive elimination of some of the gametes in plants heterozygous for the respective mutant genes. The deficit of recessive plants in the progenies of heterozygous mutant strains of peas can be attributed to this retardation. Marked differences between the various mutants with regard to the levels of various free amino acids in their pollen grains were found. Certain amino acids may be present in greatly reduced concentration or may be present in excess. In some genotypes pollen tube growth can be stimulated by adding the deficient amino acid. This is especially true for proline, valine and threonine. As far as the other amino acids are concerned, the mutants studied showed varying reactions. The germination rate of the pollen grains is reduced by proline and threonine; germination is completely inhibited by glutamine. The amino acids isoleucine, histidine and cysteine retard pollen tube growth in all the mutants investigated. This is also true for leucine which, however, has a stimulating effect in one of the chlorophyll mutants.

Notes: Summary The favourable yielding capacity of a group of X-ray inducedPisum sativum mutants makes them attractive for pea breeding. The fasciated mutant 489C produced as much as 32–92% more seed than the corresponding values of the initial line during the past 4 years. Mutants 68C and 1201A cannot exploit their favourable properties. After incorporation in different genetic backgrounds the genes in question can be expected to induce better productivity. The small-grained mutant 176A having a very good seed set could be of interest to canning industry. The early flowering mutant 46 cannot be used in practical breeding because of its heterogeneous yield properties in subsequent generations. Hybrids between these mutants were made in order to combine their useful characters. The productivity of these hybrids and their parental lines was studied and compared with the initial line. Hybrids between 176A × 68C and 1201A × 68C did not show heterosis for any characters. Hybrids of all mutants with the fasciated 489C, however, showed a marked heterosis effect for increased vigour and stem length resulting in a conspiciously high seed production.