By Stephen Daniells
A sustainable harvest of nutrient-rich, pest- and drought-resistant,
high-yield rice could be within reach thanks to recent genetic advances,
Chinese researchers have reported.
Writing in the prestigious journal Proceedings of the National Academy
of Sciences, scientists from Huazhong Agricultural University report that
most desirable traits necessary for the rice have already been isolated

Rice is recognised as the world's most important staple crop, as it is
a major source of sustenance for some 1.6bn people, the majority of which is
grown in China, Japan, Australia, the Philippines, Thailand, Indonesia and
Burma.

More than 600m people are thought to get more than half of their
calories from rice.

Given its global importance, rice is a key subject for researchers
seeking to ensure food security in the light of threats like changes in
climate and growing conditions and pests.

The new review, by Qifa Zhang, highlights the potential of the
transgenic 'Green Super Rice' (GSR), which would also require less
fertiliser.

"Development of GSR, with improved insect and disease resistances, N-
and P-use efficiency, drought resistance, high grain yield, and superior
quality, is critical for a more sustainable rice production," wrote Zhang.

Achieving such a super rice can be achieved in two stages, added
Zhang, with research firstly necessary to create elite lines carrying the
single genes. Such work is partly realised, with thorough evaluation already
performed.

The second stage focuses on combining and introducing the genes into
cultivars that could be considered to display the desired traits for the
Green Super Rice.

"Utilisation of these cultivars will result in increased rice
productivity with much reduced inputs to ensure a greater sustainability of
rice production and agriculture in general," stated Zhang.

However, serious challenges remain, most notably combining the
favourable traits in a single cultivar.

"A big challenge is the assembling process to combine all of the
favourable alleles into a single cultivar and ensure their proper
functioning," wrote Zhang. "In this regard, it may be more advantageous to
breed for hybrids than conventional pure line cultivars, because it may take
less effort to have two complementary sets of genes in two parental lines
than stacking all of the genes in a single genetic background."

The work reviewed by Zhang was supported financially by the National
Program on the Development of Basic Research, the National Special Key
Project on Functional Genomics of Major Crops and Animals, the National
Natural Science Foundation of China, and the Rockefeller Foundation.


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