Study pertaining to the availability of soil-surface rooting for rice cultivation in the Era of Petroleum Scarcity

我们利用印尼有土壤表层的水稻品种Gemdjah Beton和日本无土壤表层的水稻品种Sasanishiki杂交而成的重组自交系，阐明了控制土壤表层生根的遗传因素。我们在7号染色体长臂上发现了一个主效遗传因子，并将其命名为qSOR1(Uga等人)。2011)。我们从日本晴的种子愈伤组织再生的M2群体中发现了一个土壤-表面生根突变体。水稻突变体sor1是位于4号染色体短臂末端的Os04g0101800等位基因，引起土壤-表面生根和根向力反应改变(Hanzawa等)。2013)。利用该突变体进行的栽培试验结果表明，土壤-地表生根可能有助于提高对一些有问题的土壤类型的耐受性，如盐碱地。

We clarified the genetic factors controlling soil-surface rooting by using recombinant inbred lines derived from a cross between Gemdjah Beton, an Indonesian lowland rice cultivar with soil-surface roots, and Sasanishiki, a Japanese lowland rice cultivar without soil-surface roots. We identified a major genetic factor on long arm of chromosome 7, and then designated this QTL qSOR1 (Uga et al. 2011).We found a soil-surface rooting mutant from an M2 population that was regenerated from seed calli of a japonica rice cultivar, Nipponbare. The sor1, a rice mutant causing soil-surface rooting and altered root gravitropic response, is allelic to Os04g0101800 on the terminal region of the short arm of chromosome 4. The 33-bp deletion is responsible for the mutant phenotypes (Hanzawa et al. 2013). The result of cultivation trial by using this mutant suggest that the soil-surface rooting may be useful for increasing tolerance to some of the problematic soil types such as saline paddy field.