China achieves sweet orange genome breakthrough
Central China Agricultural University researchers spent a year assembling and annotating the genome sequence of the plant, marking the first time Chinese scientists have independently determined the genome sequence of a fruit crop.
Research team leader Deng Xiuxin, said the discovery offered an ideal research platform for biotechnology and genetic engineering in China.
The sweet orange, which originated in China, is the most commonly grown fruit tree in the world, and its production accounts for about 60% of total citrus production.
The sweet orange, mostly poly-embryonic, is highly heterozygous, which means it has dissimilar pairs of genes for any hereditary characteristic, and suffers from sterility.
China is the world's largest grower of citrus, and Chinese people have been cultivating citrus crops for 4,000 years. Statistics from the Ministry of Agriculture show that China produced 26.45 million tonnes of citrus across 2.21 million hectares in 2010.
Out of the more than 80 types of citrus species grown in China, 40% are not native to China, and half of the country's fruit production is generated from foreign breeds.
The country has been eager to see breakthroughs in the genetic research of citrus to speed up the improvement of its own citrus breeds.
Deng compared sequencing the genome of the sweet orange to opening the "black box" of the crop's life activities, a move that could help improve the fruit's traits, including color, taste, yields and disease resistance.