“Green Super Rice”

 

  Rice is the most important cereal crop and principal staple food in developing countries, particularly in Asia. Global rice production needs to keep pace with feeding the rapidly growing human population in a sustainable manner. As the main staple, rice production has to meet increasing requirements, in both quantity and quality, and should be in harmony with the environment thus ensuring a proper level of sustainability. This can be achieved by breeding Green Super Rice cultivars that leads to gradual reduction in application of pesticides, fertilizers, and water while still achieving continuous yield increase and quality improvement. Green Super Rice is defined as the rice cultivars that produce higher and more stable yield with lesser inputs. The goals of GSR can be achieved as a two-stage process. In the first stage, elite lines carrying single gene/qtl of interest are developed and thoroughly evaluated, which by themselves are useful for varietal release. In the second stage, the genes introduced into these lines will be combined in various ways to develop cultivars with the desired traits for GSR. Identification of green genes for the development of GSR involves, screening of rice germplasm, QTL mapping, screening of rice mutant libraries, microarray analysis and functional test of candidate genes. Major strategies involved in GSR development are – selective introgression, omics approach, designed QTL pyramiding and transgenic approach1. The ultimate moto of Green Super Rice breeding is “less input, more production, and better environment”.

Green Super Rice variety with enhanced tolerance to bacterial blight, blast and sheath blight was developed through marker-assisted gene pyramiding. IRBB20 (bacterial blight resistant) and Tetep (sheath blight and blast resistant) were used as donor parents for the transfer of resistant genes into the elite genetic background of ADT-43 and ASD-16. Homozygous pyramided lines showed increased resistance compared to recurrent parents3. GSR variety resistant to tungro disease was developed introgression breeding. tsv1 gene resistant to tungro was introgressed from the resistant variety Matatag 1 into the elite cultivar BRRI dhan 71. The introgressed lines obtained were tungro resistant and showed agronomic, yield and quality parameters similar to BRRI dhan 712.

Combination of approaches based on the recent advances in genomic research has to be formulated to address future challenges, with the long-term goal of developing sustainable Green Super Rice cultivars. Green Super Rice is a potential alternative for the elite cultivars that perform well only under ample of inputs. In order to address the problem of crosstalk of the biotic and abiotic stresses, Omics approaches should occupy the core component in future breeding and trait development activities4.

References:

 1. ALI, J., ANUMALLA, M., MURUGAIYAN, V. and LI, Z., 2021, Green Super Rice (GSR) traits: Breeding and genetics for multiple biotic and abiotic stress tolerance in rice. Theor Appl Genet., 13(3):1427-1442. 

2. HORE, T.K., INABANGAN-ASILO, M.A., WULANDARI, R., LATIF, M.A., NIHAD, S.A.I., HERNANDEZ, J.E., GREGORIO, G.B., DALISAY, T.U., DIAZ, M.G.Q., CH, B. AND SWAMY, B.M., 2022, Introgression of tsv1 improves tungro disease resistance of a rice variety BRRI dhan71. Sci Rep., 12(1):1881-1886. 

3. RAMALINGAM, J., RAVEENDRA, C., ARUMUGAM PILLAI, M.P., ARUMUGACHAMY, S. AND VANNIARAJAN, C., 2020, Gene pyramiding for achieving enhanced resistance to bacterial blight, blast, and sheath blight diseases in rice. Front plant sci., 11(2):591-599. 

4. YU, S., ALI, J., ZHOU, S., REN, G., XIE, H., PENG, S., MA, L. AND YUAN, D., 2022, From Green Super Rice to green agriculture: Reaping the promise of functional genomics research. Mol Plant., 15(1):9-26.