| Vol. 6 |
Kazuo WATANABE1 and Osamu KAMIJIMA2
1) International Potato Center, Apartado 5969, Lima, Peru
2) Faculty of Agriculture, Kobe University, Nada-ku, Kobe, 657 Japan
Coleoptile and mesocotyl play an important role in sprouting from soil and establishment of seedling stand (Dilday and Skinner 1988; Jones and Peterson 1976; Turner et al. 1982). Semidwarf cultures tend to show poor seddling stand probably because of their short coleoptiles and mesocotyls. To evaluated the potential of seedling establishment, the variety Shiokari and its 19 isogenic lines with different dwarf genes (Kinoshita and Shinbashi 1982) were reared in darkness to observe their mesocotyl and coleoptile elongation. The seeds were made available through the courtesy of Dr. T. Kinoshita. Dehulled seeds were aseptically grown in glass tubes at 30°C ± 2°C without light for 10 days. More than 40 seedlings per line were observed.
As shown in Table 1, we found that 1) the dwarf lies generally had shorter total length of mesocotyl and coleoptile than Shiokari, 2) the shortening effects of dwarfing genes were more prominent on mesocotyl than on coleoptile, 3) the effect of dwarfing genes on mesocotyl and that on coleoptile were not correlated (r=0.14), and 4) lines d-3,4,5, d-6 and sd-1 liad longer mesocotyl and/or coleoptile than Shiokari. Comparing with the data presented by Kinoshita and Shinbashi (1982), we also found that the effects of dwarf genes on seedling organs and those on mature plants were not correlated.
Table 1. Coleoptile and mesocotyl lengths of Shiokari and its
dwarf isogenic lines grown in darkness for 10 days
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Line Coleoptile(mm) Mesocotyl(mm) Total(mm)
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Shiokari 47.2 29.6 76.8
d-1 41.4 16.0** 57.4**
d-2 37.6* 10.6** 48.2**
d-3,4,5 42.5 39.5** 82.0
d-6 62.9** 17.7** 80.6
d-7 35.4** 21.9* 57.3*
d-10 33.1** 25.2 58.3**
d-11 45.0 15.9** 60.9**
d-12 52.2 16.3** 68.5*
d-13 46.4 22.7 68.6*
d-14 38.1* 17.1** 55.2**
d-17 34.1** 16.1** 49.6**
d-18h 32.9** 4.5** 37.3**
d-18k 48.6 7.0** 55.6**
d-27 38.6* 17.4** 56.0**
d-30 43.4 22.4* 65.7**
d-35 46.9 9.4** 56.3**
sd-1 (d-47) 51.2 34.7 85.9**
d-a 50.4 20.8* 71.1
d-b 36.6* 19.2** 55.8**
LSD(O.05) 8.11 7.06 6.74
LSD(O.01) 10.66 9.27 8.86
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*,** Differing from the value of Shiokari at 5% and 1% levels,
respectively.
References
Dilday, R. H. and S. L. Skinner, 1988. Mesocotyl/coleoptile elongation versus seedling vigor and plant height in rice. Agronomy Abstracts, ASA-CSSA-SSSA, p. 79.
Jones, D. B. and M. L. Peterson, 1976. Rice seedling vigor at suboptimal temperatures. Crop Sci. 16: 102-105.
Kinoshita, T. and N. Shinbashi, 1982. Identification of dwarf genes and their character expression in the Isogenic background. Jpn. J. Breed. 32: 219-231.
Turner, F. T., C. C. Chen and C. N. Bollich, 1982. Coleoptile and mesocotyl lengths in semidwarf rice seedlings. Crop Sci. 22: 43-46.
| Vol. 6 |