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Artificial autotetraploids of diploid perennial rye (Secale montanum guss) plants were obtained by colchicine treatment. C1, C2 and C3 generations of autotetraploid perennial rye were compared for seed set and cytological characteristics such as irregularities in metaphase i (univalents) and anaphase I and II (lagging chromosomes and/or chromatids and bridge formation) and micronuclei in tetrads. In the three generations (C1, C2 and C3) the percentage of cells with univalents was 18.51, 14.56 and 9.38% respectively. The percentage of cells with irregular anaphase i with univalents was 23.43, 15.93 and 7.85%, and for anaphase II cells it was 20.93, 16.47 and 7.16. The percentage of tetrads with micronuclei was 18.17, 14.07 and 6.17% and seed set was 27.72, 43.51 and 59.59% respectively. A negative correlation was found between seed set and the cytological characteristics investigated. The correlations among the characters investigated during meiosis division were statistically significant. Selection of vigorous plants of autotetraploid perennial rye increased seed setting by increasing the cytological balance. However, abnormalities in the early stage of meiosis division were reflected in the later stages of meiosis. [ABSTRACT FROM AUTHOR]

Meiosis was studied in five high-yielding and five low-yielding triticale genotypes. The percentage of metaphase I cells without univalents was 75.0%. The average number of univalents per cell was 0.56. Percentage of regular anaphase I cells was 80.1% and the average number of laggards per anaphase I cell was 0.48. On the other hand, 77.1% of anaphase II cells had regular chromosome distributions and the average number of laggards per anaphase II cell was 0.64. The percentage of tetrads without micronuclei was 73.5%, and the mean number of micronuclei per tetrad was calculated as 0.77. The percentage of pollen viability was 74.5%. It was determined that high-yielding genotypes were usually better than low-yielding genotypes in all traits. [ABSTRACT FROM AUTHOR]

The characters causing low seed-setting rates in induced tetraploid Lolium perenne L. were investigated. The objective of this study was to determine whether these characters could be used as criteria in the selection of regular meiosis and high seed-setting plants. The seeds of C 1 and C 2 generations of artificially obtained tetraploid perennial ryegrass were used. Cytological studies were done on the root tips and spike samples. A significant positive correlation was found between the frequency of cells showing regular anaphase I and high seed-setting rates. As a result, it was decided that this normal separation in anaphase I could be used as a selection criterion for seed set. The highly significant negative correlation that was found between the number of micronuclei and seed setting showed that this character could also be used as a selection criterion when a large population is under consideration. It was necessary to isolate aneuploids from euploid plants to increase fertility. [ABSTRACT FROM AUTHOR]