Strong Two Superior Flat Occupancy

Variety Name: Strong Two Superior Flat Occupation

Approval Number: National Rice Variety Approval No. 20216065

Breeding Institution: Hunan Aopulon Technology Co., Ltd., Hunan Agricultural University

Variety Origin: Strong 11S × Flat Occupation

Characteristics: A indica-type two-line hybrid rice variety. When grown as a single-season medium-duration rice in the middle and lower reaches of the Yangtze River, its total growth period is 131.1 days, 3.1 days earlier than the control Fengliangyou No. 4. Plant height is 119.9 cm, panicle length 25.0 cm, with 153,000 effective panicles per mu; each panicle bears 219.4 grains, with a seed-setting rate of 86.8% and a 1,000-grain weight of 24.9 g. Resistance: the comprehensive blast disease index over two years was 3.1 and 4.7, respectively; the panicle-neck blast damage rating reached the highest level of 5; bacterial leaf blight rating was 7; brown planthopper resistance rating was 9, indicating high susceptibility to brown planthopper, moderate susceptibility to blast, and susceptibility to bacterial leaf blight; heat tolerance during heading is moderate. Key rice quality parameters: milled rice recovery rate 62.0%, degree of chalkiness 3.2%, amylose content 16.5%, gel consistency 52 mm, alkali digestion value 6.5, and length-to-width ratio 4.0, meeting the Grade III standard stipulated in the agricultural industry’s “Quality Standards for Edible Rice Varieties.”

Yield Performance: In 2018, the variety was included in the regional trial for the late-maturing medium-grain indica rice group in the middle and lower reaches of the Yangtze River, achieving an average yield of 715.44 kg per mu, a 6.97% increase over the control variety Fengliangyou No. 4. In the follow-up trial in 2019, the average yield was 676.61 kg per mu, representing a 2.82% increase over Fengliangyou No. 4. Over the two-year regional trial period, the average yield was 696.02 kg per mu, a 4.68% increase compared with the control. In the 2019 production trial, the average yield was 660.72 kg per mu, a 2.40% increase over Fengliangyou No. 4.

Key cultivation techniques: 1. Precision seeding and robust seedling cultivation: For mid-season rice, sow in mid-to-late April; for transplanted seedlings, use 1.0–1.2 kg of seed per mu; for direct-seeded or broadcast-transplanted rice, use 1.5–2.0 kg per mu. Strengthen fertilizer and water management during the seedling stage and effectively control brown planthoppers. 2. Timely early transplanting to promote tillering: Transplant transplanted seedlings when they have 5–6 leaves, with a seedling age of 25–30 days; transplant dry-seeded seedlings when they have 3.5–4 leaves, with a seedling age of 15–18 days. Adopt moderate planting density and increase the number of basic seedlings by planting more densely—use a plant spacing of 20 cm × 30 cm, with three seedlings per hill, resulting in 80,000–100,000 basic seedlings per mu. 3. Enhanced fertilizer and water management with increased phosphorus and potassium application: Apply a heavy base fertilizer at 35–40 kg per mu of high-concentration compound fertilizer or 45–50 kg per mu of ordinary compound fertilizer; apply tillering fertilizer early—8–10 kg of urea per mu 5–7 days after transplanting, and 8–10 kg of potassium chloride per mu 20–25 days after transplanting. Apply panicle- and grain-fertilizer judiciously: At the end of the field-drying period just before panicle initiation, combine this with irrigation, and based on the crop’s growth condition, apply 10–12 kg per mu of high-concentration compound fertilizer and 12–15 kg per mu of potassium chloride to promote large panicles with many grains and strong grain filling. 4. Scientific water management and disease–pest control: Maintain a shallow water layer for green-up; alternate between shallow and moist conditions during tillering; conduct field drying once sufficient seedlings have formed; keep shallow water during panicle initiation and heading; alternate between wet and dry conditions during grain filling; drain the field 6–8 days before harvest. Promptly control sheath blight, blast, false smut, brown planthoppers, and stem borers, among others.

Review and Approval Opinion: This variety meets the national standards for rice variety approval and has been officially approved. It is suitable for single-season mid-season rice cultivation in the Yangtze River basin rice-growing areas of Hubei Province (excluding the Wuling Mountain region), Hunan Province (excluding the Wuling Mountain region), Jiangxi Province, Anhui Province, and Jiangsu Province, as well as in the mid-season rice-growing areas of Zhejiang Province, the northern rice-growing areas of Fujian Province, and the southern rice-growing areas of Henan Province—provided that these regions are low-incidence areas for blast disease.