Characteristics and High-Yield Cultivation Techniques of the Premium Japonica Rice Variety III You 98

III You 98 is a new premium hybrid japonica rice combination developed through cooperation between the Anhui Academy of Agricultural Sciences, China National Seed Group Corporation and Japan's Mitsui & Co., Ltd., using the A23 sterile line and the R-18 restorer line. It passed the approval of the Anhui Provincial Crop Variety Committee in August 2002. In 2004, under the unified arrangements of the China National Seed Group Corporation Lianyungang Experimental Station and the Lianyungang City Seed Station, we introduced this combination and conducted comparative trial demonstrations with varieties such as 3 You 18, Xudao 3, Yandao 8 and Lianjiajing 1. Through trial demonstrations and observational research, we clarified the characteristics of III You 98 and its premium high-yield cultivation techniques for a yield of 700 kg per mu. The summary is as follows:

1 Characteristics

1.1 Main Growth Period III You 98 hybrid japonica rice is sown in early May, transplanted on June 20, and harvested on October 18, with a total growth period of 160-163 days, about 7 days longer than 3 You 18 and more than 5 days longer than Xudao 3 and Yandao 8; the initial heading stage of III You 98 is August 20-26, and the full heading stage is August 29-September 5, with about 9 days from initial heading to full heading, 5 days longer than 3 You 18 and 4 days more than Xudao 3 and Yandao 8.

1.2 Plant Traits III You 98 has a relatively tall plant height, averaging 124.17-126.8 cm, 6-8 cm taller than 3 You 18 and about 20 cm taller than Xudao 3, Yandao 8 and Lianjiajing 1 respectively. The total number of leaves on the main stem is about 16.7, one leaf more than 3 You 18 and similar to Xudao 3, Yandao 8 and Lianjiajing 1; the arrangement of cauline leaves is similar to that of 3 You 18, Xudao 3, Yandao 8 and Lianjiajing 1, but the top three leaves are longer in length, narrower in width than 3 You 18, and larger in leaf area. The average panicle length is 25.71-26.49 cm, about 4 cm longer than 3 You 18 and about 10 cm longer than Xudao 3, Yandao 8 and Lianjiajing 1 respectively; III You 98 has relatively sparse grain setting, with 7.05-7.13 grains per unit panicle length (cm), 15.66% fewer than 3 You 18, and 23.4%, 27.48% and 33.1% fewer than Xudao 3, Yandao 8 and Lianjiajing 1 respectively.

1.3 Stress Resistance III You 98 has relatively good disease resistance. No stripe leaf blight or bacterial leaf blight was found in the field, rice blast was mild, sheath blight occurred at a moderate level, and rice false smut was present. Its disease resistance is similar to that of 3 You 18, Xudao 3 and Yandao 8. Because III You 98 has a relatively tall plant, its lodging resistance is slightly poorer than that of 3 You 18, Xudao 3 and Yandao 8, and the plants show a tendency to lean.

1.4 Main Growth Indicators According to trials, the suitable transplanting spacing for III You 98 in this locality is 23 cm x 13 cm, with about 80,000 basic seedlings per mu and about 220,000 productive panicles, which is conducive to achieving high yield. III You 98 has a relatively large population leaf area, with a leaf area index (LAI) of 5.71 at the jointing stage and a maximum leaf area index of 8.83 at the heading stage, both higher than the comparison varieties. The leaf area growth rate is faster in the early stage, at 81.37 sq m per mu per day, and the later-stage leaf area decline rate is similar to that of 3 You 18. Therefore, III You 98 has the characteristics of good population luxuriance, a relatively large leaf area index and high photosynthetic potential.

The dry matter accumulation of the III You 98 population shows the characteristic of being slower before heading and faster after heading. The average dry matter accumulation before heading is 5.53 kg per mu per day, and the average dry matter accumulation after heading is 13.65 kg per mu per day, both higher than the comparison varieties.

1.5 Premium Grain Quality According to tests by the Rice and Rice Products Quality Supervision, Inspection and Testing Center of the Ministry of Agriculture, the brown rice rate is 81.8%, the milled rice rate is 75.0%, the head rice rate is 73.6%, the grain length is 5.2 mm, the length-to-width ratio is 2.0, the chalkiness rate is 20%, the chalkiness degree is 3.8%, the transparency is grade 2, the alkali spreading value is grade 7, the gel consistency is 82 mm, the amylose content is 16.7%, and the protein content is 6.8%. The main quality indicators reach the national standard grade one, and it is rated as grade A rice in Japan.

2 High-Yield Cultivation Techniques

The yield component indicators for III You 98 at a yield of 700 kg per mu are: about 220,000 effective panicles per mu, more than 180 total grains per panicle, a seed-setting rate above 80%, and a 1000-grain weight above 23.5 g. To achieve high yield, the following cultivation steps must be carried out well.

2.1 Raising Strong Seedlings Use fertilized seedbed dry seedling raising, sow from May 5-10, with a seeding rate of 20-25 kg per mu. Before sowing, soak seeds with "25% Junwei 2 ml + Jinshuling 2 ml" for 72 hours; carry out timely chemical weed control after sowing, and spray paclobutrazol at the 1-leaf-1-heart stage. Apply 30 kg urea and 30 kg compound fertilizer (15-15-15) as base fertilizer. Use timely pesticide applications to prevent and control diseases and insect pests.

2.2 Rational Transplanting Transplant early at the appropriate time in early to mid-June, with a transplanting spacing of 23 cm x 13 cm, planting 2-3 seedlings per hill, and about 80,000 basic seedlings per mu.

2.3 Formula Fertilization According to the results of trial demonstrations, at the 700 kg-per-mu yield level of III You 98, generally about 20 kg pure nitrogen is applied per mu, with a ratio of 6-7:3-4 between the early and late periods, and at the same time phosphorus and potassium fertilizers should be increased. The specific fertilization technique is: apply 20 kg urea plus 35 kg compound fertilizer per mu as basal and tillering fertilizer; for the panicle fertilizer, when the remaining leaf age is about 2.0, apply a fertilizer balancing promotion and maintenance of 4-5 kg urea + 15 kg compound fertilizer.

2.4 Water Management In view of the characteristic that III You 98 is sensitive to water and fertilizer, on the basis of properly irrigating three times with the green-turning water, booting water and flowering water (each water layer managed for about 10 days), manage with moist conditions and intermittent irrigation at other times, and begin field drying when the number of productive tillers reaches 80%, carrying out field drying in 2-3 sessions to prevent excessive drying in one session, and rewater in a timely manner. Cut off water 7 days before harvest.

2.5 Integrated Control of Diseases and Insect Pests Carry out timely chemical weed control after transplanting and establishment. III You 98 has a relatively dark leaf color and is susceptible to damage by the striped stem borer, so pesticides should be applied in a timely manner for control. Apply pesticides at the heading and flowering stages to prevent diseases such as rice false smut and neck blast.