Distribution and RFLP Mapping of Complementary Genes Causing Hybrid Breakdown in Asian Cultivated Rice, Oryza sativa L.

JARQ : Japan Agricultural Research Quarterly
ISSN 00213551
書誌レコードID(総合目録DB) AA0068709X
33-1-001-006.pdf1000.34 KB

Weak plants were found in the BC1F1 generation in a backcrossing program aimed at introducing the wx gene from a Thai cultivar, Col. No. 15, into a Japanese cultivar, Sasanishiki, in Asian cultivated rice. These weak plants were characterized by poor growth and discoloration at the tillering stage, but they were fertile. Hybrid breakdown, which is defined as hybrid weakness and sterility detected in the F2 and later inbred generations from varietal crosses, is controlled by a pair of complementary recessive genes, hwd1 and hwd2, at unlinked loci. Two dominant genes at either the same or different loci, Hwd1/Hwd1 hwd2/hwd2, hwd1/hwd1 Hwd2/Hwd2 or Hwd1/hwd1 Hwd2/hwd2 are needed for normal growth. Using tester lines homozygous for a pair of complementary recessive genes selected in the BC1F3, the genotypes for hybrid breakdown of 100 Asian rice cultivars were tested based on the phenotype of F1 plants. Clinal variation for hybrid breakdown was observed. Cultivars with 2 dominant alleles at either hwd1 or hwd2 locus, were mainly found in insular Asia (Japan, Philippines and Indonesia), while the frequency of cultivars with 4 dominant alleles was more common in cultivars from continental Asia. Linkage analysis using RFLP markers mapped over 12 rice chromosomes indicated that hwd1 from Col.No.15 was located between RFLP markers, C701 and R2309, on chromosome 10, and hwd2 of Sasanishiki was tightly linked to 4 RFLP markers on chromosome 7. Role of hybrid breakdown in genetic differentiation of Asian cultivated rice is discussed.

作成者 Kazutoshi OKUNO Shuichi FUKUOKA
国立情報学研究所メタデータ主題語彙集(資源タイプ) Journal Article
開始ページ 1
終了ページ 6
言語 eng