| Autor: |
Rufener, G. K., St. Martin, S. K., Cooper, R. L., Hammond, R. B. |
| Zdroj: |
Crop Science; May 1989, Vol. 29 Issue: 3 p618-622, 5p |
| Abstrakt: |
A larval antibiosis screening technique was applied to three soybean [Glycine max(L.) Merr.] populations to determine the inheritance of resistance to Mexican bean beetle [Epilachna varivestis(Mulsant)]. The F1, F2, and F3generations (five F3plants per F2plant) of crosses between ‘Williams’ (susceptible) and L76‐0049, L78‐608, and L76‐0328 (resistant) were screened along with the parents. Mean weight of surviving larvae after 10 d of feeding on detached leaves was used as the measure of antibiosis. The resistance of F1plants was intermediate to that of their parents. Data from the F1of Williams ✕ L76‐0049 and Williams ✕ L76‐0328 indicated a small degree of dominance for resistance. The distributions of F2and F3phenotypes were continuous and unimodal. Skewness toward susceptibility occurred in Williams ✕ L76‐0328, but symmetry was evident in the other crosses. Heritability estimates (single F2plant basis) ranged from 0.33 to 0.48 when calculated from F3data, and from 0.11 to 0.22 when calculated from the covariance of F2plants and their F3progeny. Estimates of heritability derived from F2and parental data were larger but had large standard errors. Gene number estimates by the method of moments, and frequency of recovery of parental phenotypes suggested that the number of segregating resistance loci was small. Provided selection was no more intense than 2.5%, expected genetic gain from selection among individual F2plants was greater if a large number of plants were screened with a single determination per plant than if one‐half or one‐third that number were screened with two or three determinations per plant, respectively. |
| Databáze: |
Supplemental Index |
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