Effects of Major Genes Controlling Morphology of Panicle in Rice.

Murai, Masayuki; lizawa, Masashi

doi:10.1270/jsbbs1951.44.247

Cited by 21 publications

(35 citation statements)

References 5 publications

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“…Ur1 significantly reduced panicle number per plant under the genetic backgrounds of 'Shiokari' and other varieties (Nagao et al 1958, Murai and Iizawa 1994, Murai 1999). However, no significant effect of Ur1 on this trait was noticed under all the growing conditions, with and without sd1, in the present study.…”

Section: Discussionmentioning

confidence: 99%

“…The variation of this trait in 2000 was principally due to unfertilization. The sterile spikelet with whity-translucent hull ("Hakufu" in Japanese) and cylindrical spikelet lacking its palea were frequently found in panicles at the Ur1/Ur1 genotype under genetic backgrounds of Hokkaido varieties (Nagao et al 1958, Murai and Iizawa 1994, Murai 1999. Hokkaido is one of the coolest rice-growing regions in the world, and the earliest maturing varieties of rice have been grown now and in the past.…”

Section: Discussionmentioning

confidence: 99%

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Effects of a Major Gene Ur1 Characterized by Undulation of Rachis Branches on Yield and its Related Traits in Rice.

et al. 2002

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An incompletely dominant gene Ur1 is characterized by undulation of primary and secondary rachis branches. The gene increases spikelet number per panicle owing to increase of secondary branches. The Ur1/Ur1, Ur1/+ and +/+ genotypes with sd1 (denoted by u, h and d, respectively, viz. three dwarfs) and those without sd1 (U, H and T, respectively, viz. three talls) were produced under the common genetic background of a japonica variety Taichung 65. The six genotypes were grown in 2000. Yield and its related traits were measured. Analysis of variance on yield indicated that the effect of Ur1 was significant whereas the effects of sd1 and the Ur1 × sd1 interaction were nonsignificant. Genotypes u and h had significantly higher yields than d; h showed the highest yield of all genotypes. The three talls had yields in the order of H ≥ U ≥ T (H > T). Regarding spikelet number per panicle, the genotypes were in the order of u = U > h ≥ H > T > d, reflecting the principal effect of Ur1. Regarding panicle number per m 2 , the effect of Ur1 was not significant. The ripened-grain percentages of the six genotypes were almost in the reverse order of spikelet number per panicle. The 1000 grain weight of the genotypes was in the order of U ≅ u ≤ h ≤ H ≤ d < T. Sink size-2 (single grain weight × fertilized-spikelet number per m 2 ) showed a high positive correlation with yield. As for LAI, there were no significant differences among the six genotypes. The total weight per m 2 at maturity for the three dwarf genotypes were in the order of h ≥ u ≥ d (h > d). As for harvest index, u and h were higher than d. Similar results were obtained for the three dwarf genotypes under three fertilizer levels in 1998. Thus, Ur1 enlarged sink size through increase of spikelet number per m 2 resulting in higher yield. Consequently, Ur1 may be utilized for developing high yielding inbred varieties and F 1 varieties at the Ur1/+ genotype.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Effects of a Major Gene Ur1 Characterized by Undulation of Rachis Branches on Yield and its Related Traits in Rice.

et al. 2002

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“…2A; Nagao et al, 1958;Murai and Iizawa, 1994). Because Ur1 is a dominant mutant located on the distal region of the long arm of chromosome 6 (Nagao and Takahashi, 1963) where APO1 resides, we hypothesized that Ur1 might also be a dominant allele of APO1.…”

Section: Isolation Of Mutants With Increased Inflorescence Branchingmentioning

confidence: 97%

Expression Level ofABERRANT PANICLE ORGANIZATION1Determines Rice Inflorescence Form through Control of Cell Proliferation in the Meristem

et al. 2009

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Two types of branches, rachis branches (i.e. nonfloral) and spikelets (i.e. floral), are produced during rice (Oryza sativa) inflorescence development. We previously reported that the ABERRANT PANICLE ORGANIZATION1 (APO1) gene, encoding an F-box-containing protein orthologous to Arabidopsis (Arabidopsis thaliana) UNUSUAL FLORAL ORGANS, suppresses precocious conversion of rachis branch meristems to spikelets to ensure generation of certain number of spikelets. Here, we identified four dominant mutants producing an increased number of spikelets and found that they are gain-of-function alleles of APO1. The APO1 expression levels are elevated in all four mutants, suggesting that an increase of APO1 activity caused the delay in the program shift to spikelet formation. In agreement with this result, ectopic overexpression of APO1 accentuated the APO1 gain-of-function phenotypes. In the apo1-D dominant alleles, the inflorescence meristem starts to increase in size more vigorously than the wild type when switching to the reproductive development phase. This alteration in growth rate is opposite to what is observed with the apo1 mutants that have a smaller inflorescence meristem. The difference in meristem size is caused by different rates of cell proliferation. Collectively, these results suggest that the level of APO1 activity regulates the inflorescence form through control of cell proliferation in the meristem.

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“…Taichung 65 (Table 1). Four of them, fon1-1 (floral organ number1-1) (Nagasawa et al 1996, Nagato andNagasawa 1997), dl-sup1 (drooping leaf-superman1) (Nagato and Nagasawa 1997), ur2 (undulated rachis 2) (Iwata and Omura 1984) and ri (verticillate rachis) (Iwata andOmura 1984, Murai andIizawa 1994), were reported earlier. The other 14 mutants, fm 2, fm 4, fm 14, fm 20, fm 23, fm 24, fm 55, fm 60, fm 61, TCM2084, TCM2542, TCM2830, TCM2902 and TCM3064, were identified from a M 2 population of Taichung 65 subjected to mutagen treatment with methylnitroso-urea, and they were designated by the strain number.…”

Section: Plant Materialsmentioning

confidence: 88%

Mutations in Panicle Development Affect Culm Elongation in Rice

2003

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Internode elongation of the rice culm begins almost simultaneously with the change from the vegetative phase to the reproductive phase. Although this synchronism suggests the existence of an interaction between the panicle development and culm internode elongation, little information is available about panicle and internode interaction. In this study, we examined 18 mutants from cv. Taichung 65 that were defective in panicle and/or spikelet development. The 18 mutants were classified into three groups by the organ in which the major mutant phenotypes were observed; (1) mutants with aberrant rachis/branches, (2) mutants with aberrant spikelets/flowers, (3) mutants with aberration in both rachis and spikelets. Most of the mutants with aberrant rachis/branches showed an abnormal culm elongation. In contrast, those defective in only spikelet development showed an almost normal culm elongation. The correlation analysis showed that panicle traits were significantly correlated with the length of the distal one or two internodes. Principal component analysis of the culm internode length showed that the mutants defective in rachis/branch development were positioned far from the wild type, while those with normal panicles and aberrant spikelets were distributed near the wild type. These analyses revealed that culm elongation, especially for the upper internodes, was affected by the early developmental mode of panicles. Although the mechanism by which panicle development regulates the elongation of upper internodes has not yet been identified, the present study indicates that the elucidation of early panicle development is essential for a comprehensive understanding of culm internode elongation.

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Effects of Major Genes Controlling Morphology of Panicle in Rice.

Cited by 21 publications

References 5 publications

Effects of a Major Gene Ur1 Characterized by Undulation of Rachis Branches on Yield and its Related Traits in Rice.

Effects of a Major Gene Ur1 Characterized by Undulation of Rachis Branches on Yield and its Related Traits in Rice.

Expression Level ofABERRANT PANICLE ORGANIZATION1Determines Rice Inflorescence Form through Control of Cell Proliferation in the Meristem

Mutations in Panicle Development Affect Culm Elongation in Rice

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