The characteristics of plant type and physiological indices for photosynthesis were analyzed using two super hybrid rices, Liangyoupeijiu and LiangyouE32 as materials, and an indica hybrid, Shan-you63 as a control. Ba...The characteristics of plant type and physiological indices for photosynthesis were analyzed using two super hybrid rices, Liangyoupeijiu and LiangyouE32 as materials, and an indica hybrid, Shan-you63 as a control. Based on the present analysis and various theories and breeding practices on rice plant type, a model of plant ideotype for super hybrid rice (indica) in the lower reaches of Yangtze River Valley was proposed. This was: a length of 35 - 40 cm for top leaf with a width of 2 cm, and that of 50 - 55 cm and 55-60 cm, respectively, for the second and third leaves from top, meanwhile, having a leaf angle of 5°, 10°and 15° respectively, and a curvature of 1 - 1. 5 cm-1for the leaf face at heading stage; the uppermost three leaves keeping their activities for as long as 70 d, which could lead a LAI of 3 at full ripeness; loose plant type with thin (SLW=2.5-3 g cm-2, dry weight) and curve-slant leaves during early growing stage, and compact plant type by thick (SLW=4 - 5 g cm-2) and erect leaves during the middle and late growing stages; with a coefficient of light extinction of 0. 3 - 0. 4, which allowed for an optimal LAI high of 8-10 during the middle growth period; plant height of 110-120 cm, with 2 - 4 cm basal internode and a long uppermost internode occupying 45% of total stem length; 25 - 28 cm panicle with 8-10 spikelets per centimeter showing bend-type in ripening; a rich chlorophyll which led to a high net photosynthetic rate, and tolerance to light shading and photooxidation which is of benefit to increasing the adaptability to varying light conditions.展开更多
Hybrid rice has contributed greatly to the self-sufficiency of food supply In China. To meet the future demand for rice production, a national program on super rice breeding was established In China In 1996. The corre...Hybrid rice has contributed greatly to the self-sufficiency of food supply In China. To meet the future demand for rice production, a national program on super rice breeding was established In China In 1996. The corresponding targets, breeding strategies and most significant advances are reviewed In this paper. New plant type models have been modified to adjust to various rice growing regions. In recognition of the Importance of applying parents with Intermediate subspecies differentiation In Increasing F1 yield, medium type parental lines were selected from populations derived from Inter-subspecies crosses with the assistance of DNA markers for subspecies differentiation. Results also indicate that a substantial increase of blomass Is the basis for further enhancement of the grain yield potential, and amelioration of leaf characteristics Is helpful In Increasing the photosynthetic rate. Thirty-four super hybrid rice varieties have been released commercially, growing In a total area of 13.5 million hm2 and producing 6.7 thousand million kg more rice In 1998-2005. Although remarkable progress has been made In super hybrid rice breeding In China, selections on the root system and Integration of more blotechnologlcal tools remain a great challenge.展开更多
文摘The characteristics of plant type and physiological indices for photosynthesis were analyzed using two super hybrid rices, Liangyoupeijiu and LiangyouE32 as materials, and an indica hybrid, Shan-you63 as a control. Based on the present analysis and various theories and breeding practices on rice plant type, a model of plant ideotype for super hybrid rice (indica) in the lower reaches of Yangtze River Valley was proposed. This was: a length of 35 - 40 cm for top leaf with a width of 2 cm, and that of 50 - 55 cm and 55-60 cm, respectively, for the second and third leaves from top, meanwhile, having a leaf angle of 5°, 10°and 15° respectively, and a curvature of 1 - 1. 5 cm-1for the leaf face at heading stage; the uppermost three leaves keeping their activities for as long as 70 d, which could lead a LAI of 3 at full ripeness; loose plant type with thin (SLW=2.5-3 g cm-2, dry weight) and curve-slant leaves during early growing stage, and compact plant type by thick (SLW=4 - 5 g cm-2) and erect leaves during the middle and late growing stages; with a coefficient of light extinction of 0. 3 - 0. 4, which allowed for an optimal LAI high of 8-10 during the middle growth period; plant height of 110-120 cm, with 2 - 4 cm basal internode and a long uppermost internode occupying 45% of total stem length; 25 - 28 cm panicle with 8-10 spikelets per centimeter showing bend-type in ripening; a rich chlorophyll which led to a high net photosynthetic rate, and tolerance to light shading and photooxidation which is of benefit to increasing the adaptability to varying light conditions.
基金Supported by the National Program on Super Rice Breeding, the Ministry of Agriculture, National High-Tech and Development Program of China （863）, the Ministry of Science and Technology and Provincial Program （8812）, Zhejiang Province, China. Publication of this paper is supported by the National Natural Science Foundation of China （30624808）.
文摘Hybrid rice has contributed greatly to the self-sufficiency of food supply In China. To meet the future demand for rice production, a national program on super rice breeding was established In China In 1996. The corresponding targets, breeding strategies and most significant advances are reviewed In this paper. New plant type models have been modified to adjust to various rice growing regions. In recognition of the Importance of applying parents with Intermediate subspecies differentiation In Increasing F1 yield, medium type parental lines were selected from populations derived from Inter-subspecies crosses with the assistance of DNA markers for subspecies differentiation. Results also indicate that a substantial increase of blomass Is the basis for further enhancement of the grain yield potential, and amelioration of leaf characteristics Is helpful In Increasing the photosynthetic rate. Thirty-four super hybrid rice varieties have been released commercially, growing In a total area of 13.5 million hm2 and producing 6.7 thousand million kg more rice In 1998-2005. Although remarkable progress has been made In super hybrid rice breeding In China, selections on the root system and Integration of more blotechnologlcal tools remain a great challenge.
