Reference "The effects on the culm length and other agronomic characters caused by semidwarfing genes at the sd-1 locus in rice"

Reference ID

3240

Title

The effects on the culm length and other agronomic characters caused by semidwarfing genes at the sd-1 locus in rice

Source

Japanese Journal of Breeding, 1993, vol. 43, pp. 267-275

Authors (4)

Ogi-Y	Kato-H
Maruyama-K	Kikuchi-F

Abstract

A large number of semidwarf high yielding rice varieties have been developed by
using local varieties or artificial mutants. However, semidwarfing genes of
practical importance are limited to the sd-1 locus. In the present study, we
evaluated the differences in the effects of semidwarfing genes at the sd-1 locus
of chromosome 1 on the culm length and other agronomic characters among four
isogenic lines which have the genetic background of Norin 29. As the results, it
was suggested that the four semidwarf isogenic lines have multiple alleles at
the sd-1 locus by the comparison of culm length. The shortening effect on culm
length was strongest for SC-TN1(N) which has a semidwarfing gene from ''Taichung
Native 1'', followed by SC-SRN(N) which has a semidwarfing gene from
''Shiranui'', SC-AJNT(N) which has a semidwarfing gene from ''Ai-Jio-Nan-Te''
and SC-CPSLO(N) which has a semidwarfing gene from ''CP-SLO''. Furthermore, it
was found out that for all four isogenic lines the semidwarfing gene sd-1
inhibited elongation of lower internodes more than upper internodes and this
fact could be favourable for lodging resistance because lodging often occur at
the lower internodes. There were no differences between Norin 29 and its
semidwarf isogenic lines with respect to the mean length of the parenchyma cell
in the upper internode. However, in the case of cell number, all semidwarf
isogenic lines decreased significantly compared with Norin 29. It was considered
that the semidwarfing genes at the sd-I locus contribute to the shortening of
the culm length through their inhibitory effects on cell division during
internode elongation. As for other agronomic characters, the panicle length was
not significantly reduced, the number of panicles was increased, and the grain
size was not affected. So no significant negative pleiotropy that accompanied
the shortening of the culm length was observed for all four isogenic lines.
Thus, we can conclude that the semidwarfing genes at the sd-1 locus are very
much useful and easy to use for improving cultivars.