Satoshi Yonekawa

Two-dimensional image analysis of the shape of rice and its application to separating varieties

To analyze the shapes of brown rice and polished rice, a series of measurements by image processing on Japonica, Indica and Javanica types composed of four rice varieties with three polishing methods were carried out. Area, perimeter, maximum length, maximum width, compactness and elongation were measured. The maximum length, maximum width and elongation of a rice particle defined here were different from the traditional dimensions such as length and width. Further, separating the rice varieties by the shape difference of a rice particle was examined. From the result of the investigation on brown rice and polished rice, separating the rice varieties was possible at a probability level of 95.4% with combined dimensions and shape factors or with single ones.

Three-dimensional image analysis of the shape of soybean seed

Abstract An apparatus for three-dimensional (3-D) measurement with a structured light system was made to study the shape of soybean seed; its axial length, surface area, volume, particle density, compactness and sphericity were measured. From the analysis on a reduced sample of the seed population, the typical size and shape of seed were calculated. The 3-D properties of surface area and volume were expressed as functions of seed mass. In general, soybean seed appears to be uniform in shape over a wide range of sizes.

Effect of Brassinolide applied at the meiosis and flowering stages on the levels of endogenous plant hormones during grain-filling in rice plant (Oryza sativa L.)

Abstract Brassinolide (BL), a brassinosteroid, applied to rice plants in pots promotes panicle ripening. In this study, we examined the effect of BL applied at the meiosis and flowering stages on endogenous levels of various plant hormones in the panicles of the rice plant (cv. Nipponbare) grown in a field-temperature (F-temp; 25°G on average ranging from 22 to 33°C during ripening periods) condition and low-temperature (L-temp; in phytotron kept at 22°C/ 17°C) condition in rice cultivation season in Japan. The content of either free- or bound-IAA in the rice spikelet at the milk-ripe stage (10 - 15 days after heading) was higher in the F-temp condition than in the L-temp condition. BL applied twice, 10 days before and on the day of heading, slightly increased the free-IAA content and greatly increased the bound-IAA content at the milk-ripe stage in both condition. BL slightly decreased the ABA content of the spikelet at the milk-ripe stage in the F-temp condition, and slightly increased it in the L-temp condition. The rate of ethylene production was measured only in the F-temp condition. It was markedly high at the milk-ripe stage and low at the dough-ripe stage (21 days after heading). BL treatment clearly increased the rate of ethylene production from the panicles under both light and dark conditions at the milk-ripe stage. These results suggest that BL, which promotes rice ripening, influences in the levels of endogenous plant hormones to play an important role in controlling the sink function during grain-filling.

Comparison of No-tillage Farming among the Three Different Soils III. Adoption to the Volcanic Soil (Soil Texture SiC).

わが国の畑作における不耕起栽培は,最 近までほ とんど体系的には研究されておらず,耕 地環境や歴 史的背景の異なる欧米での不耕起栽培技術の持つ意 義や問題点と,わ が国のそれとは異なると考えられ る2),3).さらには,国 内においても気候,土 壌の相違 から不耕起栽培のもたらす効果や問題点は地域によ って異なることが予測される.一 方,近 年とくに指 摘される栽培環境の見直しや保全の重要性,生 産コ ストの低減などからも不耕起栽培のもつ特徴が注目 されている.こ うした状況にありながら,わ が国で の大型機械の利用を前提とした畑作の不耕起栽培に 関する資料の蓄積は少ない.本 研究は,畑 作の不耕 起栽培に関する基礎資料を得る目的で,土 性の異な る3地 域で同時並行的に同一の基本設計のもとに比 較実験 を行 った もの で ある. 本 報 では,前 報1),7)までの火 山灰 土壌(東 京,土 性 L),砂 質 土壌(島 根,土 性LS)に 続 いて,新 潟 での 火山灰 土壌(土 性SiC)に お け る3年6作 の実 験結 果 につ いて報告 す る.

Differences in the Rates of Ethylene Production and Growth between the Calluses Derived from Rice (Oryza sativa L.) and Soybean (Glycine max (L.) Merr.)

Summary The differences in the rates of ethylene production and growth between the calluses derived from the seeds of rice (16 cultivars of Oryza sativa L., Japonica and Indica types) and soybean (10 cultivars of Glycine max (L.) Merr.) were investigated. On the medium containing 2,4-dichlorophenoxyacetic acid (2,4-D) and benzylaminopurine (BAP), soybean calluses produced a larger amount of ethylene (208-1541 nLg–1 FW 24 h–1) than rice calluses (8-37 nLg–1 FW 24 h–1) and the rate of ethylene production from the calluses of both species greatly varied with the cultivar. The combined application of 2,4-D and BAP greatly increased the ethylene production rate and the growth of calluses in soybean, but not in rice. Moreover, the addition of BAP to the medium strikingly promoted ethylene production in soybean calluses cultured on the medium containing 2,4-D, but not in those cultured on the medium containing indolebutyric acid (IBA). The rate of ethylene production in both soybean and rice negatively correlated with the growth of calluses. The ethylene production and growth of calluses cultured under various conditions greatly differed between soybean and rice, and also varied with the cultivar of each species. The different aspects of the growth and ethylene production between soybean and rice calluses may represent the difference between dicots and monocots.

Assessment of No-tillage Farming. VI. Renovation of No-tillage Field Passed 11Years.

In this study, we practiced a renovation trial by plowing to the continuous no-tillage field passed 11 years. The field seemed to be deteriorated for cultivation judging from the changes of soil condition and crop yield. The renovation trial based on the two-factors experiment with three levels of tillage and three levels of materials for soil improvement was started at April in 1991.1) Water content of soil in NC (renovation of notillage plot) was equal to that in CC (continuous plowing plot), but soil hardness (penetration resistance) in NC was higher than that in CC.2) Field efficiency of plowing in NC was higher than that in CC. Depth of tillage in NC was equal to that in CC, but the average value of width of tillage estimated from total width of plowed area and number of furrow in NC was wider than that in CC.3) Fuel consumption per unit area in NC was 5% higher, and the consumption per unit time in NC was 14% higher than those in CC.4) Specific resistance of soil estimated from the measured values, such as fuel consumption and traveling speed, in NC was higher by 8% than that in CC.5) From the result of analysis of variance for dry matter yield of corn, there was the significant difference with 1% level for tillage factor only. When we adopted the value of 100 to crop yield in CC as a standard, the crop yield in NC was 97, that was 67 in NN (continuous no-tillage plot), respectively.6) From the result of analysis of variance for the quantity of weed, there was the significant difference with 5% level for the tillage factor only. The quantity of weed in NN was much than any other plots.7) In NN, notable pH drop was observed at the soil layer of 5-10cm in depth. The pH profile in NN at the layer of 0-20cm approached to that in CC which showed an uniform distribution of pH.8) In spite of the deteriorated field by continuous no-tillage farming for 11 years, the crop yield almost recovered to the yield level in CC by only once tillage as a renovation.