Studies and Applications on Dynamic Plant Type Breeding Theories in Double Cropping Super Oryza sativa L. subsp. hsien Ting in South China

Improving a plant type and shaping a“rice ideal plant type”through plant type breeding are powerful technical guarantees for increasing rice yield potential. There exists a basic regular pattern for the growth and development of rice (Oryza sativa L. ), at each stage of which, there is an optimum disposition of morphological traits and the corresponding physiological features in the plants of population. The disposition of plant type components change as the growth and development stage proceeds, and it is called dynamic plant type. According to the practical situation in rice planting area of South China, the characteristics of the“dynamic plant type”were compared when different double cropping super Oryza sativa L. subsp. hsien Ting (OSHT) varieties (combinations) planted under different ecological environments at the early and late seasons. The theory system of dynamic plant type breeding for super OSHT was first established and was used in superhigh yield OSHT breeding in South China. It was made to change the concept of “plant type component” from qualitative and indistinct to dynamic and quantitative, which more clearly reflect the characteristics of the main morphological and physiological traits of super OSHT varieties (combinations) in the area and further bring to light the regularity of high yielding formation. The theory system has been used to guide the breeding of double cropping super OSHT or high-quality and super high-yield rice in South China, and it can improve the breeding efficiency and shorten the breeding period. A number of super OSHT or high quality and super-high yield rice varieties (combinations) have been bred and applied in South China, which showed the important guiding significance of this theory system for super OSHT breeding or high quality and super-high yield rice breeding in South China.