Six different aneuploid types for chromosome 5 and diploid siblings were planted in the greenhouse this year. They were Triplo 5 (2n = 15); Triplo 5L (2n = 14 + 1 telo 5L); Triplo 5S (2n = 14 + 1 telo 5S); Ditelotgtrasomic 5S (2n = 14 + 2 tlo 5S); Acrotrisomic 5S^5L (2n = 14 + 1 acro 5S^5L and Diacrotetrasomic 5S^5L (2n = 14 + 2 acro 5S^5L ). All seeds were germinated and transplanted at the same time. Plants were grown under identical environment and normal diploid plants were grown as a check. Pollen and seed fertilities were studied carefully. The results are listed in Table 1.

The data in Table 1 suggested that all these aneuploid types had good pollen fertility except Diacrotetrasomic 5S^5L. In comparison with disomic plants, Triplo 55 had very high pollen fertility (96.3%). Triplo 5L was next (94.9%) followed by Acrotrisomic 5S^5L (93.8%) and Triplo 5 (92.6%). For extra two chromosomes, Ditelotetrasomic 5S showed better pollen fertility than Diacrotetrasomic 5S^5L.

Seed fertilities varied from high to low for trisomic types with the highest triplo 5S, followed by an acrotrisomic 5S^5L, and the lowest Triplo 5. For aneuploid plants with two extra chromosomes, Ditelotetrasomic 5S showed much better seed fertility (68.9%) than Diacrotetrasomic 5S^5L (12.0%).

The results suggested that pollen fertilities were influenced by the types and numbers of extra chromosome. For the seed fertility, extra one 5S had no or almost no harmful effect, and the extra 5L had certain negative effect. While in tetrasomic plants, the two doses of the extra chromosomes were too high for normal performance, and the seed fertility reduced. However, ditelotetrasomic 5S showed much higher seed fertility (68.9%) than Diacrotetrasomic 5S^5L (12%) since the latter had two extra pieces of proximal chromosome segments of 5L.