Reference "Identification of hybrid sterility gene loci in two cytoplasmic male sterile lines in rice"

Reference ID

7023

Title

Identification of hybrid sterility gene loci in two cytoplasmic male sterile lines in rice

Source

Crop Science, 2000, vol. 40, pp. 640-646

Authors (3)

Devanand-P-S	Rangaswamy-M
Ikehashi-H

Abstract

In hybrid rice (Oryza sativa L.) breeding, spikelet sterility is a barrier to
attaining enhanced heterosis in crosses between different groups or subspecies
of rice. Our objective was to identify the hybrid sterility gene loci (HSGLi) in
two indica cytoplasmic male sterile A lines (`IR58025A' and `IR62829A') and
their corresponding maintainer B lines (`IR58025B' and `IR62829B'). To detect
the HSGL, three testers, `IR36' (indica cultivar), `Dular' (indica wide
compatibility variety [WCV]) and `Nekken 2' (japonica WCV) were crossed to the
two groups in the form of IR36/WCV//B and A//IR36/WCV. The level of spikelet
fertility in the F1 progeny of three-way crosses was differentiated by
morphological and isozyme marker genes at the known HSGLi, S5, S7, S8, and S15
on chromosomes 6, 7, 6, and 12, respectively, and by two new HSGLi, on
chromosomes 3 and 11. The levels of pollen fertility were differentiated by
specific marker alleles among segregating genotypes in the cytoplasmic male
sterile (cms) background. The presence of marker alleles from IR36 was
associated with high pollen fertility, while marker alleles from Dular and
Nekken 2 were associated with low pollen fertility due to the effect of HSGLi in
the cms background. The effect of dominant and recessive restorers from IR36 was
not estimated due to lack of appropriate markers. To alleviate problems of
hybrid sterility, the level of sterility should be tested in crosses between
maintainers and restorers before the former are used for backcrossing to create
new cms lines.