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Materials and methods

The test line J-11 was selected from a Chinese common wheat landrace (Triticum aestivum L.), Sichuan White Wheat complex, by Luo et al (1990). The crossability of this line with rye is close to 100%. Two sets of monosomic lines, Abbondanza and Chinese Spring, were used in the monosomic analysis. From each monosomic line, two or three monosomic plants were pollinated with J-11. Three to five monosomic and at least one disomic plants were mitotically selected from each F1 population. The selected F1 plants were then pollinated with rye (Secale ceraele L. cv. Qinling).

Number of seed-set per spike was counted 20 days after pollination. The crossability of a test line with rye was represented by the average percentage of seed set of all the spikes pollinated of that line. The crossability of each spike was converted to angle and the converted data were then subjected to analysis of variance.

For cytological checking of the chromosome numbers, pollen-mother-cells (PMCs) or root-tip cells were fixed with a 3:1 (95% ethanol-glacial acetic acid) solution and then stained by Feulgen procedure.


Results

Analysis by using Abbondanza monosomic lines
Monosomic analysis of the J-11 line with Abbondanza monosomic lines showed that all the disomic F1 plants had very low crossability with rye (an average of 2.1 %). This results suggested that cultivar Abbondanza carried only the Kr alleles on all the corresponding loci. On the other hand, the crossabilities of the monosomic 1A, 5A,and 5B F1 plants were 53.0%, 36.1% and 56.9%, respectively (
Table1). The analysis of variance for the crossabilities of the F1 monosomic plants indicated significant diffrences within the monosomic 1A, 5A, 5B and 5D lines and also between these monosomic F1 lines and the remaining monosomic F1 lines (Table 2). No significant difference was observed within the remaining monosomic F1 lines. The effects of chromosomes 1A, 5A and 5B on the wheat-rye crossability were observed to be significantly greater than any other chromosomes. The effect of chromosome 5B was observed to be greater than chromosome 5A. The effect of chromosome 1A was not significantly lower than either chromosome 5A or 5B. The data also showed that the effect of monosomic 5D F1 line was greater than that of disomic F1 line at the 0.10 significant level.

Analysis by using Chinese Spring monosomic lines
Since Chinese Spying carries only the kr alleles, all the F1 lines from the crosses between J-11 and Chinese Spring monosomic lines had good crossabilities with rye as expected (
Table1). However, the analysis of variance showed that significant differences did exist between lines (Table 2). On the other hand, no significant defference was observed within F1 monosomic IA, 5A and 5B lines. The wheat-rye crossability of the F1 monosomic 5D line was found to be significantly different from those of the F1 monosomic 1A, 5A and 5B lines at the 0.05, 0.01 and 0.10 significant levels, respectively. These results indicate that chromosomes 1A, 5A and 5B of the J-11 line a pparently had greater influence on the crossability with rye than other chromosomes did. The crossabilities of the F1 monosomic 1A, 5A and 5B lines were obviously lower than those of the other F1 lines. This result suggests that hemizygous kr alleles might be less effective than homozygous kr alleles. On this aspect, the effect of chromosome 5A was reduced larger than those of chromosomes 1A and 5B, and chromosome 5B was less effective than chromosome 1A.

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