Characteristics of the Hybrid Japonica Rice Changyou 3 and Its High-Quality, High-Yield Cultivation Techniques
Changyou 3 (also known as Changyou 00-8) is a new three-line hybrid japonica rice combination bred by the Changshu Municipal Institute of Agricultural Sciences. It was approved by the National Crop Variety Approval Committee in 2005 (approval number: Guoshen Dao 2005036). The male sterile line of this variety, Wuyunjing 7A, obtained the national variety right certificate in September 2005 (certificate number: CNA20010203.6). Changyou 3 is suitable for promotion and planting as a single-season late japonica rice in areas of Jiangsu, Zhejiang, Shanghai, Anhui and Hubei where rice blast and bacterial leaf blight occur only mildly.
1 Variety Characteristics
This variety is a japonica-type three-line hybrid rice. When grown as single-season late rice in the middle and lower reaches of the Yangtze River rice region, its average whole growth period is 148.1 days, 0.6 day earlier than the control Xiushui 63. The plant type is moderate, with 6-7 elongated internodes above ground and 18-19 total leaves on the main stem; the flag leaf is erect, growth is luxuriant, and color conversion at maturity is good. Plant height is 108.2 cm, and the stems are thick and sturdy with elasticity, showing strong fertilizer tolerance and lodging resistance. The number of effective panicles is 160,000-180,000 per mu, panicle length is 18.6 cm, total grains per panicle are 160-170, seed-setting rate is 85.3%, threshing is easy, and 1,000-grain weight is 27-28 g.
2 Main Advantages of the Variety
2.1 Suitable maturity period For single-season planting in the Taihu rice region, sowing is generally done in mid-to-late May, full heading occurs in early September, and maturity occurs in late October, with a whole growth period of about 163 days, making it suitable for planting in the Taihu rice region and the single-season late japonica rice region in the middle and lower reaches of the Yangtze River.
2.2 High yield In 2002, it participated in the regional trial of the single-season late japonica group in the middle and lower reaches of the Yangtze River, with an average yield of 600.4 kg per mu, 5.26% higher than the control Xiushui 63 (extremely significant); in the 2003 continued trial, the average yield was 575.29 kg per mu, 8.99% higher than the control Xiushui 63 (extremely significant). In the 2004 production trial, the average yield was 639.15 kg per mu, 10.34% higher than the control Xiushui 63, ranking first in the trial.
2.3 Excellent grain quality This combination has excellent grain quality. According to unified sampling from the national variety trial of the single-season late japonica group in the southern rice region from 2002 to 2003 and testing by the Rice and Rice Products Quality Supervision, Inspection and Testing Center of the Ministry of Agriculture: brown rice rate 84.4%, milled rice rate 76.4%, head rice rate 72.5%, grain length 4.9 mm, length-to-width ratio 1.7, chalky grain rate 28%, chalkiness degree 3.5%, transparency grade 1, alkali spreading value 7.0, gel consistency 76 mm, and amylose 16.1%, reaching Grade 3 of the national "High-Quality Rice" standard. Tasting in various places showed that the cooked rice has good palatability.
2.4 Strong resistance According to the resistance identification results of the Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences from 2000 to 2001: when Changyou 3 was inoculated with 6 physiological races of rice blast, except for being moderately susceptible to race ZB1, its reaction type to the other 5 physiological races was all grade 0; against 4 physiological races of bacterial leaf blight, it showed resistance to moderate resistance; and it was resistant to sheath blight (reaction type R). According to inoculation resistance identification in Zhejiang and Hubei: rice blast averaged grade 6.1, bacterial leaf blight grade 7, brown planthopper grade 9, and rice false smut occurred rather severely, so attention should be paid to its control.
3 High-Yield Cultivation Techniques
The panicle-grain structure for a Changyou 3 yield of 600-650 kg/mu is: about 160,000-180,000 panicles per mu, 160-170 total grains per panicle, seed-setting rate above 85%, and 1,000-grain weight 27-28 g. Its cultivation strategy is: sow at the right time, grow strong seedlings, promote early tillering, reasonably control the mid-season population, increase the panicle-forming rate, and take the path of balancing panicles and grains; on the basis of ensuring panicle number, focus on large panicles to increase the seed-setting rate and 1,000-grain weight.
3.1 Sow at the right time and grow strong seedlings For water-raised large seedlings, the suitable sowing period is May 20-25 in the Taihu rice region, with a seedling age of 30 days (other rice regions can determine the sowing and transplanting period through trials to ensure heading and flowering under suitable climatic conditions). The net sowing rate in the seedling field is 10-12.5 kg/mu, and the ratio of seedling field to main field is 1:10-12. Before sowing, carry out chemical seed treatment; apply 13-15 kg/mu of pure nitrogen in the seedling field, together with a certain proportion of phosphorus and potassium fertilizer.
3.2 Transplant at the right time and plant at a reasonable density Transplant in early late June. Planting density: spacing 13.2 cm x 26.4 cm or 16.5 cm x 26.4 cm, 15,000 hills/mu, with 1-2 seed seedlings per hill.
3.3 Scientific fertilization and rational irrigation Changyou 3 has strong heterosis and a well-developed root system, with strong fertilizer uptake capacity. For fields of medium fertility, apply 15 kg/mu of pure nitrogen; for fields with high fertility, it may be appropriately reduced by 1-2 kg/mu, while for fields with poor fertility, increase it by 1-2 kg/mu and increase the application of phosphorus and potassium fertilizer. The suitable N:P:K ratio is 1:0.4:0.5. Specific fertilization method: basal fertilizer: apply 25 kg/mu of high-concentration compound fertilizer and 25 kg/mu of ammonium bicarbonate; for tillering-promoting fertilizer, apply 10 kg of urea; for tiller-preserving fertilizer, apply 15-20 kg of high-concentration compound fertilizer. In the Taihu rice region, nitrogen fertilizer application should be finished by July 10-15, but 7.5 kg of potassium chloride may be supplemented. Do not apply panicle fertilizer, so as to avoid increasing green grains and empty grains and lowering the seed-setting rate, thereby affecting yield.
In water management, the requirements are shallow-water transplanting, deep-water establishment, maintaining a shallow water layer during the tillering stage, and draining the field when the expected number of stems and tillers is reached, preferably with multiple light drainings. The peak seedling number should be controlled at 210,000-220,000 per mu, with a panicle-forming rate above 80%. In the later stage, keep the field moist, and stop irrigation one week before harvest. Ensure green stems and yellow grains, and mature fully while still alive.
3.4 Control diseases and pests well Pay attention to timely control of rice blast, bacterial leaf blight, rice false smut, small brown planthopper, rice leaf roller and other diseases and pests.