About Lesson
- M1:
- Several hundred seeds are treated with a mutagen and are speculated.
- In general, the number of treated seeds is so adjusted as to give rise to -500 fertile M1 plants at the harvest.
- Care should be taken to avoid outcrossing; this can be achieved either by planting the M1 population in isolation or by bagging the inflorescences of M1 plants or even the whole M1 plants.
- M2:
- About 2,000 progeny rows are grown.
- Careful and regular observations are made on the M2 rows. But only distinct mutations are detected in M2 because the observations are based on single plants.
- All the plants in M2 rows suspected of containing new mutations are harvested separately to raise individual plant progenies in M3.
- If the mutant is distinct, it is selected for multiplication and testing.
- M3:
- Progeny rows from individual selected plants are grown in M3.
- Poor and inferior mutant rows are eliminated.
- If the mutant progenies are homogeneous, two or more M3 progenies containing the same mutation may be bulked.
- Mutant M3 rows are harvested in bulk for a preliminary yield trial in M4.
- M4:
- Preliminary yield trial is conducted with a suitable check, and promising mutant lines are selected for replicated multilocation trials.
- M5-M7:
- Replicated multilocation yield trials are conducted.
- The out-standing line may be released as a new variety.
- The low yielding mutant lines, however, should be retained for use in hybridization programmes.
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