Introduction to the Hybrid Japonica Rice Variety Changyou No. 1

"Changyou No. 1" is a new "three-line" high-quality hybrid japonica rice variety bred in 1998 by the Changshu Agricultural Science Institute of Jiangsu Province. It passed Jiangsu provincial approval in January 2002 and national approval in November 2003 (National Approved Rice 2003068). At the same time, the male-sterile line of this combination, Wuyunjing No. 7 A, has applied for new variety protection, with the number CN20010203.6. Because this variety has the advantages of good quality, high yield, strong resistance, wide adaptability and high seed production yield, it has now been promoted and planted on 200,000 mu in the late japonica rice areas of Jiangsu, Zhejiang, Shanghai, Anhui, Hubei and other provinces (municipalities), showing broad prospects for use. This variety was developed by the Changshu Agricultural Science Institute, Suzhou Seed Company and Changshu Seed Company.

Good quality. According to the physicochemical index determination by the Rice and Rice Products Supervision and Testing Center of the Ministry of Agriculture, its brown rice rate is 85.5%, milled rice rate 76.8%, head rice rate 73.9%, chalkiness rate 17%, chalkiness degree 2.0%, transparency grade 2, alkali spreading value grade 7.0, gel consistency 92, amylose content 17.1%, and protein content 7.2%, reaching the second-class standard of the newly issued national standard (GB/T17891-1999) for high-quality rice. It was rated as high-quality rice in Jiangsu Province.

High yield. First, it stood out in trials at all levels and of all types. In 2001, it participated in the national single-season late japonica rice regional trial in the southern rice region, with an average yield of 584.7 kg per mu, 6.16% higher than the control Xiushui No. 6, ranking first. In 2002, it continued to participate in the national regional trial, with an average yield of 601.5 kg per mu. In the same year, it participated in the production trial, with a yield of 623.2 kg per mu, 5.46% higher than the control Xiushui No. 63. Second, it has high and stable yield in large-area planting. In 2002, 73.5 mu were planted in Diankou Town, Zhuji City, Zhejiang, with an average actual yield of 505.6 kg/mu, 10.8% higher than Bayou No. 8. In 2003, 60 mu were planted as single-season late rice in Xiongtou Village, Xiaonan District, Xiaogan City, Hubei Province, and at the Dongshantou Original Seed Farm, with an average yield of 552.0 kg per mu, 8.02% higher than Ejingza No. 1 and 12.65% higher than conventional rice.

The high and stable yield of Changyou No. 1 is mainly reflected in full grains, large panicles and heavy grains, and a coordinated panicle-grain structure. The plant height of this combination is 105-110 cm, the effective panicle number per mu is 160,000-170,000, the total grain number per panicle is 165-170, the seed-setting rate is about 85%, the 1000-grain weight is 27-28 g, and the yield per mu is stable at about 600 kg.

Suitable maturity period. In the southern Jiangsu rice area, it is sown in mid-to-late May, transplanted in mid-to-late June, with a seedling age of about 30 days, full heading in early September, and maturity in late October, with a whole growth period of about 160 days. It is suitable for planting in the Taihu rice area and the single-season late japonica rice area in the middle and lower reaches of the Yangtze River.

Strong resistance. Resistance identification shows that Changyou No. 1 is highly resistant to rice blast and resistant or moderately resistant to bacterial leaf blight. Sheath blight occurs relatively lightly. This combination is tolerant to fertilizer and resistant to lodging, grows cleanly and neatly, and at maturity has green stems and yellow grains with good ripening color.

Relatively high seed production yield. Changyou No. 1 seed production shows the characteristics of a small sowing interval between the parents, relatively easy flowering encounter, and a relatively high outcrossing seed-setting rate. In 2002, 400 mu of seed production were carried out in Kunshan, Suzhou, with an average yield of 200 kg per mu. Among them, the farmer Qian Julin produced seed on 20 mu, with a yield per mu exceeding 250 kg.

Good economic benefits. Compared with the conventional varieties currently promoted, it increases yield by about 25 kg per mu. Calculated at 1.6 yuan per kg of paddy, this can increase income by 45 yuan per mu; the net rice yield per mu can be increased by 12 kg. Calculated at 2.4 yuan per kg of rice, this can increase income by 28.8 yuan per mu. In addition, it can save seedling fields, reduce transplanting labor, and lower nitrogen fertilizer input, saving a comprehensive 10 yuan per mu in costs and expenditures. Planting Changyou No. 1 can increase income and reduce expenditures by a total of 83.8 yuan per mu.