Inhibiting Gene for a Late-Heading Gene Responsible for Photoperiod Sensitivity in Rice (Oryza sativa)

Two indica varieties, IR36 and ‘Suweon 258’ (“S”)
are middle-heading in southern Japan. 36U, also middle-heading, is
an isogenic line of IR36 carrying Ur1 (Undulate rachis-1) gene.
However, late-heading plants segregated in the F2 population from
the F1 of S × 36U, and so did in the following generations. The
concerning lateness gene is designated as Ex. From the F8 generation,
isogenic-line pair of early-heading and late-heading lines, denoted by
“E” (ex/ex) and “L” (Ex/Ex), were developed. Genetic analyses of
heading time were conducted, using F1s and F2s among L, E, S and
36U. The following inferences were drawn from the experimental
results: 1) L, and both of E and 36U harbor Ex and ex, respectively;
2) Besides Ex, S harbors an inhibitor gene to it, i.e. I-Ex which is a
novel finding of the present study. 3) Ex is a dominant allele at the
E1 locus.





References:
<p>[1] F. Kubota, N. Tanaka, and S. Arima, &quot;Study on productive ecology of a
high yielding japonica-indica hybrid rice cultivar &quot;Suweon258&quot;,&quot; Japan.
Jour. Crop Sci., vol.57 (2), 1988, pp. 287-297.
[2] H. Inoue, H. Nishida, Y. Okumoto, and T. Tanisaka, &quot;Identification of
an early heading time gene found in the Taiwanese rice cultivar
Taichung 65,&quot; Breed. Sci., vol. 48, 1998, pp.103-108.
[3] I. Ohshima, F. Kikuchi, Y. Watanabe, and C. Asahi, &quot;Genetic analysis
of heading time in a cross between two indica varieties with inhibitor
genes for photoperiod sensitivity,&quot; Jpn. J. breed., vol. 43, 1993, pp. 101-
106.
[4] K. H. Tsai, and H. I. Oka, &quot;Genetic study on yield capacity and
adaptability in crop plants. 2. Analysis of genes controlling heading
time in Taichung 65 and other rice varieties,&quot; Bot. Bull. Acad. Sinica,
vol. 7, 1966, pp. 54&ndash;70.
[5] K. Ichitani, Y. Okumoto, and T. Tanisaka, &quot;Genetic analysis of the rice
cultivar Kasalath with special reference to two photoperiod sensitivity
loci, E1 and Se1,&quot; Breed. Sci., vol. 48, 1998, pp. 51-57.
[6] L. V. Dung, T. Inukai, and Y. Sano, &quot;Dissection of a major QTL for
photoperiod sensitivity in rice: its association with a gene expressed in
an age-dependent manner,&quot; Theor. Appl. Genet., vol. 97, 1998, pp. 714-
720.
[7] M. F. Chandraratna, &quot;A gene for photoperiod sensitivity in rice linked
with apiculus color,&quot; Nature, vol. 171, 1953, pp. 1162-1163.
[8] M. Poonyarit, D.J. Mackill, and B.S. Vergara, &quot;Genetics of photoperiod
sensitivity and critical daylength in rice,&quot; Crop Sci., vol. 29, 1989, pp.
647-652.
[9] M. Yokoo, and F. Kikuchi, &quot;Multiple allelism of the locus controlling
heading time of rice, detected using close linkage with blast-resistance,&quot;
Jpn. J. Breed., vol. 21, 1977, pp. 123-130.
[10] M. Yokoo, and F. Kikuchi, &quot;Monogenic control of basic vegetative
phase and photoperiod-sensitive phase in rice,&quot; Japan. J. Breed., vol. 32,
1982, pp. 1-8 (in Japanese with English summary).
[11] M. Yokoo, F. Kikuchi, A. Nakane, and H. Fujimaki, &quot;Genetical analysis
of heading time by aid of close linkage with blast resistance in rice,&quot;
Bull. Natl. Inst. Agric. Sci., vol. D31, 1980, pp. 95-126. (in Japanese
with English summary).
[12] M. Yokoo, and H. Fujimaki, &quot;Tight linkage of blast resistance with late
maturity observed in different Indica varieties of rice,&quot; Jpn. J. Breed.,
vol. 21, 1971, pp. 35-59.
[13] S. Sato, I. Sakamoto, K. Shirakawa, and S. Nakasone, &quot;Chromosomal
location of an earliness gene Ef1 of rice, Oryza Sativa L,&quot; Jpn. J. Breed.,
vol. 38, 1988, pp. 385&ndash;396.
[14] S. Peng, K. G. Cassman, S. S. Virmani, J. Sheehy, and G. S. Khush,
&quot;Yield potential trends of tropical rice since the release of IR8 and the
challenge of increasing rice yield potential,&quot; Crop Sci., vol. 39, 1999,
pp. 1552-1559.
[15] T.A. Trieu, S. Malangen, A. Dozaki, T. Akaoka, Y. Takemura, M.
Urabe, and M. Murai, &quot;Single-genic segregation in heading date,
observed in a progeny (F8 generation) of the cross between two indicatype
varieties in rice,&quot; Shikoku J. Crop Sci., vol. 47, 2010, pp. 44-45.
[16] T. T. Chang, B. S. Vergara, and C. C. Li, &quot;Component analysis of
duration from seeding to heading in rice by the basic vegetative phase
and photoperiod sensitive phase,&quot; Euphytica, vol. 18, 1969, pp. 79-91.
[17] Y. Ito, S. Sato, and Y. Sano, &quot;Developmental changes of phyllochron in
near-isogenic lines of rice (Oryza sativa L.) with different growth
durations,&quot; Euphytica, vol. 119, 2001, pp. 271-278.
[18] Y. Okumoto, and T. Tanisaka, &quot;Trisomic analysis of a strong
photoperiod-sensitivity gene E1 in rice (Oryza sativa L.),&quot; Euphytica,
vol. 95, 1997, pp. 301&ndash;307.
[19] Y. Okumoto, T. Tanisaka, and H. Yamagata, &quot;A new tester line for
analyzing heading time genes in rice,&quot; Rice Genet. Newsl., vol. 8, 1991,
pp. 129-131
[20] Y. Sano, &quot;Genetic Comparisons of chromosome 6 between wiId and
cultivated rice,&quot; Jpn. J. Breed., vol. 42, 1992, pp. 561-572.
[21] Y. Sato, and K. Hayashi, &quot;Varietal variations in basic vegetative phase
and photosensitive phase among Japanese native cultivars of rice,&quot; Jpn.
J. Breed., vol. 35, 1985, pp. 72-75 (in Japanese with English summary).</p>