Strategies for developing Green Super Rice

Abstract

From a global viewpoint, a number of challenges need to be met for sustainable rice production: (i) increasingly severe occurrence of insects and diseases and indiscriminate pesticide applications; (ii) high pressure for yield increase and overuse of fertilizers; (iii) water shortage and increasingly frequent occurrence of drought; and (iv) extensive cultivation in marginal lands. A combination of approaches based on the recent advances in genomic research has been formulated to address these challenges, with the long-term goal to develop rice cultivars referred to as Green Super Rice. On the premise of continued yield increase and quality improvement, Green Super Rice should possess resistances to multiple insects and diseases, high nutrient efficiency, and drought resistance, promising to greatly reduce the consumption of pesticides, chemical fertilizers, and water. Large efforts have been focused on identifying germplasms and discovering genes for resistance to diseases and insects, N- and P-use efficiency, drought resistance, grain quality, and yield. The approaches adopted include screening of germplasm collections and mutant libraries, gene discovery and identification, microarray analysis of differentially regulated genes under stressed conditions, and functional test of candidate genes by transgenic analysis. Genes for almost all of the traits have now been isolated in a global perspective and are gradually incorporated into genetic backgrounds of elite cultivars by molecular marker-assisted selection or transformation. It is anticipated that such strategies and efforts would eventually lead to the development of Green Super Rice.

Fig. 1.

Schematic representation of combinations of genes and approaches for the development of GSR.

Fig. 2.

Pest resistance of Minghui 63 individually harboring five different Bt genes. (A) Minghui 63 carrying Cry1Ab/c against natural infestation of leaffolders (28). The middle row is the control, and flanking rows are transgenic. (B) Minghui 63 carrying Cry1Ab/c against heavy artificial infestation of yellow stemborer (28). The left row is transgenic, and the right is the control. (C) Minghui 63 carrying Cry1Ab against natural infestation of leaffolders and stemborers (Y. Lin and Q.Z., unpublished data). The left row is the control, and the right is transgenic. (D) Minghui 63 carrying Cry1Ac against natural infestation of leaffolders and stemborers (Y. Lin and Q.Z., unpublished data). The left row is transgenic, and the right is the control. (E) Minghui 63 carrying Cry1C against natural infestation of leaffolders. The left row is transgenic, and the right is the control. (F) Minghui 63 carrying Cry2A against natural infestation of leaffolders. The left row is transgenic, and the right is the control.