水稻根의 生理的活力 및 그 關聯形質의 品種間差와 育種上의 利用에 關한 硏究 = Studies on the Physiological Root Activity and its Related Characteristics of Rice Varieties for Application to Rice Breedi

다국어 초록 (Multilingual Abstract)

The present experiments were conducted to obtain basic information on the selection of parent materials for crossing in rice breeding program during 1968~'69 and 1972.
Varieties tested in this experiment were 8 Korean and Japanese varieties, respectively.
The morphological traits and physiological activity of roots were observed in order to see the fundamental informations on them in rice varieties differing in their origin and also to find out the interrelationships among the characteristics of roots and aerial parts.
Further experiment with 26 varieties and lines having different plant types was carried out to provide basic informations which could be applied to a rice breeding program to make selections for better regional adaptibility.
The results obtained are summarized as follows.
1. A highly significant positive correlation was found between the diameter of cross section and that of air-space in cortex of culm-base and also the diameter of root was positively correlated with the diameter of cross section of culmbase and with the number of parenchyma cells in cortex of root.
2. The diameter of root showed highly significant positive correlation with the number of vessels in metaxylem of root as well as with tension of root. It is considered that the Korean rice varieties have better conducting and Ventilating system between the top and the roots of rice plant as compared to the Japanese rice varieties.
3. The physiological root activity was positively correlated with the diameter of air-space in cortex of culm-base and with the number of parenchyma cells in cortex of root as well as with the number of vessels in metaxylem of root. Based on these facts, close relationship was clarified between physiological activity and histo-morphological characteristics of root. As compared with Japanese rice varieties, Korean varieties appeared to be higher in physiological activity of root in favor of thicker culm-base, larger air-space in cortex of culm, more number of parenchyma cells in cortex of root and more number of vessels in metaxylem of root. It may be concluded that Korean rice varieties have better adaptibility to less favorable conditions for rice growing especially where the AKIOCHI occurs than Japanese varieties.
4. Korean rice varieties involved in this experiment showed higher activity of upper and lower nodal roots before heading, but the activity was sharply decreased after heading. The root activity of Japanese varieties, however, was slowly decreased although it was lower than that of Korean varieties before heading. Therefore, the range of variation in root activity at different growth stages tended to be greater in Korean rice varieties than in Japanese.
5. Rice varieties with higher root activity before heading tended to have erect flag leaf, higher content of chlorophyll in flag leaf, and to show slower decomposition of the chlorophyll. It was also found that the variety with high root activity before and after heading had higher content of chlorophyll in leaf blades and was higher photosynthetic activity of the leaves.
Significant varietal differences were observed in these characteristics.
6. The root activity before heading appeared to have no close relationship with Fe₂O₃or MnO content in the leaves. Antagonistic relationship, however, was found between the content of the 2 elements in the leaves.
7. Close relationship was recognized between the root activity after heading and the grain yield. It may be concluded that the root activity before heading does not affect the grain yield as much as the root activity at the later growth stage. Particularly, higher grain yield was obtained when the root activity index〔1/(range of variation in root activity/average root activity)x100〕was high. It is suggested that the rice variety could produce more grain yield when it has stable higher root activity in later growth stage.
8. A close relationship was found between the root activity and the rooting ratio at the seedling stage.
9. A highly significant positive correlation was found between the root activity and the number of green leaves at the later growth stage(heading to ripening stage). This indicates that the higher the root activity was the more the number of green leaves in later growth stage.
10. Above result was confirmed by the fact that removal of lower leaves resulted in the reduction of root activity. Therefore, it would be possible to diagnose indirectly the root activity by observing the number of green leaves of the rice plant in later growth stage when a breeder makes selections in the hybrid population.

목차 (Table of Contents)

• 목차
• I. 緖言 = 1
• II. 硏究史 = 1
• III. 材料 및 方法 = 3
• IV. 試驗結果 = 4
• 1. 稈基 및 根의 形態와 根의 生理的 活力과의 關係 = 4
• 가. 稈基의 形態와 根의 形態와의 關係 = 5
• 나. 根의 生理的 活力과 稈 및 根의 形態와의 關聯性 = 8
• 2. 根의 生理的 活力과 地上部 生育形質 및 收量과의 關係 = 9
• 가. 生育時期別 根의 生理的 活力의 品種間 差異 = 10
• 나. 根의 生理的 活力과 葉의 몇가지 形質 및 成分含量과의 關係 = 11
• 다. 根의 生理的 活力의 品種間 差와 收量과의 關係 = 13
• 3. 根의 生理的 活力 利用에 依한 系統選拔의 效率 = 14
• 가. 成苗의 素質과 根의 生理的 活力 = 14
• 나. 根의 生理的 活力과 地上部形質과의 關係究明에 依한 根活力 間接診斷法 = 16
• V. 考察 = 18
• VI. 摘要 = 21
• 參考文獻 = 22
• Summary = 25