Identification of an early heading time gene found in the Taiwanese rice cultivar Taichung 65

Hiromo Inoue, Hidetaka Nishida, Yutaka Okumoto, Takatoshi Tanisaka

Research output: Contribution to journalArticle

17 Citations (Scopus)

Abstract

An early heading time gene tentatively designated as 'v' and nonallelic to E1, E2, E3 and Ef-1 was detected in the Taiwanese rice cultivar Taichung 65 (T65) (Okumoto et al. 1992b). This gene remarkably accelerated heading time. The allelism test of this gene to a photoperiod insensitivity gene See at the Se-1 locus was performed using the progenies from reciprocal crosses between T65 and a heading time tester line ER. The role of this gene in the rice cultivation in Taiwan was also discussed on the basis of photoperiod responses of T65, ER and a heading time tester line LR. T65 was found to have the genotype E1E1E2E2E3E3 vv ef- 1ef- 1, while ER and LR had the genotypes E1E1e2e2E3E3Se-1eSe-1eEf-1Ef-1 and E1E1e2e2E3E3Se- 1(u)Se - 1(u)Ef-1Ef-1, respectively. ER also carried a rice blast resistance gene Pi-z(t) closely linked to Se- 1e on chromosome 6. E1, E2, E3 and Se - 1(u) were all photoperiod sensitivity genes, and ef- 1 at the Ef- 1 locus remarkably increased the duration of the basic vegetative growth period (BVG). In the F2, no distinct transgressive segregants appeared, and the three genotypes (Pi-z(t) Pi-z(t), Pi-z(t) +, ++) for the Pi-z locus in the F2 exhibited almost the same range and the same mean for heading time. These facts imply that 'v' is identical with Se-1e. T65 exhibited a far longer BVG than the two tester lines. The critical day-lengths (CDLs) of T65 and ER were longer than 16 h, while the CDL of LR ranged between 14 h and 15 h: the CDL of LR was shorter than those of T65 and ER. When compared to LR, T65 and ER exhibited a small retarding effect under super optimum photoperiod (RES), and did not differ in RES. These results indicate that the low photoperiod sensitivity of T65 is due to the action of 'v' (=Se- 1(c)). Since the long BVG of T65 is attributed to the action of ef- 1, it is considered that 'v' (=Se- 1e) and ef- 1 are very important genes for rice cultivation in Taiwan, where natural day-length is short even in summer and seasonal changes are negligible.

Original languageEnglish
Pages (from-to)103-108
Number of pages6
JournalBreeding Science
Volume48
Issue number2
DOIs
Publication statusPublished - Jun 1998
Externally publishedYes

Keywords

  • Basic vegetative growth
  • Gene analysis
  • Heading time
  • Oryza sativa
  • Photoperiod sensitivity

ASJC Scopus subject areas

  • Agronomy and Crop Science
  • Genetics
  • Plant Science

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