Hostname: page-component-7479d7b7d-rvbq7 Total loading time: 0 Render date: 2024-07-11T23:23:07.759Z Has data issue: false hasContentIssue false

Dormancy of paddy seeds in relation to different moisture contents of grains and dates of harvests

Published online by Cambridge University Press:  27 March 2009

H. P. Sikder
Affiliation:
Rice Research Station, Government of West Bengal, Chinsurah, Hooghly, India

Summary

Two dormant varieties of rice were harvested three times at intervals of 7 days after grain development and the seeds were subjected to different sunning and controlled humidity storage treatments. Germination percentages and moisture contents of the grains were recorded at intervals of seven days after harvest.

It was noted that the dormancy of the dormant rice seeds was broken early when the seeds were subjected to continuous sunning from sunrise to sunset, followed by the treatment where the seeds were preserved under 0 % humidity conditions at room temperature. There was no break of dormancy of rice seeds when the seeds were preserved under 94 % humidity conditions.

It was further noted that when the age of the seeds at the time of a germination test remained the same, the earlier the harvest, the earlier was the break of dormancy; and when the lapse of time after harvest remained the same at the time of a germination test, the later the harvest, the better was the germination.

It is suggested that dryness of the seeds helps in the early break of dormancy and wetness retards or completely stops the dormancy-breaking reactions. On drying, the kernels of rice seeds shrink in volume more than the glume covers resulting in an air-space between the glumes and the kernels. This air-space helps air-diffusion in and out of the seeds, resulting in quicker oxidation-reaction processes or possibly embryo respiration, and consequently the dormancy is broken early. Increase in temperature accelerates such reactions. It is further suggested that the dormancy of rice seeds depends on the interactions between the ‘embryo-sensitivity to inhibitors’ and the ‘state of oxidation-reaction processes’ inside the seeds.

Type
Research Article
Copyright
Copyright © Cambridge University Press 1973

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Jennings, P. R. & Jesus, J. De (1964). Effect of heat on breaking seed dormancy in rice. Crop Sci. 4, 530–33.Google Scholar
Meyer, B. S. & Anderson, D. B. (1952). PI. Physiol. 2nd ed.New York: Van Nostrand.Google Scholar
Mikkelsen, D. S. (1967). Germination inhibitors as a possible factor in rice dormancy. Int. Bice Gommn Newsl.(special issue of 1967), pp. 132–45.Google Scholar
O'Brien, F. E. M. (1948). The control of humidity by saturated salt solutions. J. scient. Instrum. 25, 73–6.Google Scholar
Roberts, E. H. (1962). Dormancy in rice seed. III. The influence of temperature, moisture and gaseous environment. J. exp. Bot. 13, 7594.Google Scholar
Roberts, E. H. (1964). A survey of the effects of chemion cal treatments on dormancy in rice seed. Physiologia PL 17, 3043.Google Scholar
Roberts, E. H. (1965). Dormancy in rice seed. IV. Varietal responses to storage and germination tern-peratures. J. exp. Bot. 16, 341–49.Google Scholar
Sikder, H. P. (1967). Dormancy of paddy seeds in relation to different seed treatments. Expl Agric. 3, 249–55.CrossRefGoogle Scholar
Sircar, S. M. & Dey, Bharati (1963). Dormancy and viability of the seed of rice (Oryza sativaL.). Int. Symp. Physiol. Ecol. and Biochem. of Germination, Greifswald.Google Scholar