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Trisomics in Solanum chacoense: Fertility and Cytology
Heiyoung K. Lee and P. R. Rowe
American Journal of Botany
Vol. 62, No. 6 (Jul., 1975), pp. 593-601
Published by: Botanical Society of America, Inc.
Stable URL: http://www.jstor.org/stable/2441937
Page Count: 9
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Twenty trisomic plants found in the progeny 3x x 2x crosses in Solanum chacoense and their F1 trisomics obtained by 2x + 1 x 2x crosses were studied with respect to their fertility and cytology. The female transmission of the extra chromosome in the trisomics varied from 2 to 60%. The transmission frequencies of F1 trisomics were similar to their parent trisomics in most of the lines. The transmission through the pollen ranged from 0 to 20%. Female and male fertility of the parent trisomics was high. They produced an average of 37 seeds per pollination as the female or as the male parent. The F1 trisomics produced about half the seed set of their parent trisomics. The extra chromosomes of six trisomics were identified by pachytene analysis. They were isochromosomes for the long arms of chromosomes I, IV and IX and the short arms of IV, IX and XII. Chromosome morphology of the extra chromosomes in pachytene stage was described. A chromosome association of 12 II + 1 I was found in 66 % of the cells at MI. About 29 % of the cells had one trivalent and 5 % had three or five univalents. The frequency of trivalent formation was not affected by the length of the extra chromosome. The possibility of univalent shift in secondary trisomics was discussed.
American Journal of Botany © 1975 Botanical Society of America, Inc.