Rice Mutation Breeding in China
Recent studies on Asian wild rice and land races of cultivars indicate that South Asia is most likely the main centre of origin of cultivated rice. Differentiation of the indica (hsien) rice would have occurred in South Asia, and that of the japonica (keng) rice in South-eastern and Eastern Asia. In the Chinese common wild rice, well isolated populations appeared more primitive than others, as the enzymatic variations they carried were limited. In tracing the domestication and differentiation of cultivated rice, they may be taken as prototypes.
The central and lower Yangtze basin seems to be the cradle of Chinese rice cultivation as evidenced by recent archaeological excavations. In fact, during the reporting officer's duty travel to China, a visit was organized to Humudu Rice Museum of the Zhejiang Province. This museum offers a display of fossil rice discovered in the 1970s and dated back -7000 to -5000 years BP. Such a great discovery has helped, together with the identification of a few other sites, establishing China as one of the centres of origins of cultivated Asian rice.
The extraordinary wealth of mutant lines displayed by Prof. Dianxing Wu from the Zhejiang University in the Humudu Experimental Station is certainly in the direct heritage of this ancient rice cultivation tradition. Prof. Wu and his team have produced a large population of M2 putative rice mutant lines of over one million individuals.
Batches of these lines conserved in various germplasm banks in private as well as public sites are being characterised phenotypically every year under field conditions. Several high value added mutants have already been released and adopted by farmers; moreover, their products have been promoted for commercialisation, for example the new variety 'Zhefu Liangyou12' in 2009.
Several other advanced mutant lines are under multi-location trials prior to release: the mutant rice RS111 providing source for improved starch for diabetes & obesity-affected people, the high zinc rice (with more than 30mg/Kg of Zinc in the polished rice), additionally a secondary mutant derived from this rice and presenting small round grains is being promoted as baby food.
The close relationship between the breeders, the farmers and the agro-food industry is quite outstanding and may inspire more than one breeder as the best way for promoting their work on mutation induction and also getting the much needed additional funding.