Historical Review of Semidwarf Rices and Breeding of a New Plant Type for Sustainable Agriculture

水稻短桿品種歷史的回顧暨永續性農業新株型育種

胡兆華(Chao-Hwa Hu)

《臺中區農業改良場研究彙報》 38期 (1993/03) Pp. 45-63

https://doi.org/10.6956/BTDAIS.199303.0045

摘要

The evolution of rice was not under the pressure of fertilization and its relationship to insects and parasites until recent years. DGWG semidwarf (sd1) is a major gene mutation which has pleiotropic effects causing dark erect leaves and compact assemly stems that respond to N application, making the plant look like a bush. High density of planting with intensive fertilization maximizes the productivity and the use of space. However, it also provides an excellent environment for insect and parasite reproduction. The occurrence of pest epidemics has resulted in a disaster for rice history.This paper analyzes plant morphologies in relationship to high yield and presents a new semidwarf plant type (sd6) secured from an induced mutation. The reduced tillering compensated by more spikelets per panicle and the open-stemmed morphology provide better ventilation within the plant and direct sunlight to the bottom of the plant, an unfavorable environment for insect and fungus growth which is a primary concern in the agro-ecosystem. This will reduce pesticide use, water pollution and soil damage. The new plant type provides for a natural self-protection system.Studies on increasing genetic diversity of cultivars, the sd6 semidwarf of Indica long-grain has been crossed with sd1 semidwarf of Japonica short-grain sweet rice. The F1 plants showed high fertility (85%) and the F2 seed-set segregated into a 9(＞70): 3(60-69%): 3(40-59%):1(＜40%) ratio. The variation of brown rice size (L/W ratio) of F3 seeds fell into the normal distribution range between two parents. This variation was exemplified by the sample of rice seeds excavated form Homudo, China, whice is estimated to be about 7000 years old. The results suggest that the Japonica Indica cross can be traced to the original genetic diversity of the rice species, Oryza sativa L.Selection on convientional semidwarf vs. open-stemmed semidwarf plant type with various grain size, glutinous vs. non-glutinous, different maturity, etc. were done. The high fertility F2 segregants were found bred true at advanced generations. Yielding tests on convientional and new cultural method will be carried out. The results of breeding primarily obtained are encouragement.

關鍵字

水稻 ； 短稈 ； 集約栽培 ； 病蟲害管理 ； 生態體系 ； 遺傳岐異性 ； 稉秈稻育種

並列摘要

The evolution of rice was not under the pressure of fertilization and its relationship to insects and parasites until recent years. DGWG semidwarf (sd1) is a major gene mutation which has pleiotropic effects causing dark erect leaves and compact assemly stems that respond to N application, making the plant look like a bush. High density of planting with intensive fertilization maximizes the productivity and the use of space. However, it also provides an excellent environment for insect and parasite reproduction. The occurrence of pest epidemics has resulted in a disaster for rice history.This paper analyzes plant morphologies in relationship to high yield and presents a new semidwarf plant type (sd6) secured from an induced mutation. The reduced tillering compensated by more spikelets per panicle and the open-stemmed morphology provide better ventilation within the plant and direct sunlight to the bottom of the plant, an unfavorable environment for insect and fungus growth which is a primary concern in the agro-ecosystem. This will reduce pesticide use, water pollution and soil damage. The new plant type provides for a natural self-protection system.Studies on increasing genetic diversity of cultivars, the sd6 semidwarf of Indica long-grain has been crossed with sd1 semidwarf of Japonica short-grain sweet rice. The F1 plants showed high fertility (85%) and the F2 seed-set segregated into a 9(＞70): 3(60-69%): 3(40-59%):1(＜40%) ratio. The variation of brown rice size (L/W ratio) of F3 seeds fell into the normal distribution range between two parents. This variation was exemplified by the sample of rice seeds excavated form Homudo, China, whice is estimated to be about 7000 years old. The results suggest that the Japonica Indica cross can be traced to the original genetic diversity of the rice species, Oryza sativa L.Selection on convientional semidwarf vs. open-stemmed semidwarf plant type with various grain size, glutinous vs. non-glutinous, different maturity, etc. were done. The high fertility F2 segregants were found bred true at advanced generations. Yielding tests on convientional and new cultural method will be carried out. The results of breeding primarily obtained are encouragement.

並列關鍵字

rice ； semidwarf ； intensive culture ； pest-management ； ecosystem ； genetic diversity ； Indica-Japonica breeding