Shennong 7 (formerly known as Shennong 9457 rice)

Characteristics: This variety is a conventional japonica-type rice variety. Grown in the early-maturing rice regions of Northeast and Northwest China, its whole growth period is 152.3 days, 7 days later maturing than the control Jiyujing. Plant height is 93.8 cm, total grains per panicle 73.1, seed setting rate 90.4%, and 1000-grain weight 26.2 g. Rice blast resistance grade 7. Main rice quality indicators: head rice rate 68.4%, chalky grain rate 12%, chalkiness degree 1.2%, gel consistency 85 mm, and amylose content 16.3%.

Yield performance: In 2001, it participated in the Jiyujing group regional trial of the northern rice region, with an average yield of 588.7 kg per mu, a 2.9% increase over the control Jiyujing (not significant); in 2002, in the continued trial, the average yield was 607 kg per mu, a 1.2% decrease compared with the control Jiyujing (not significant); the two-year average yield of the regional trial was 597.9 kg per mu, a 0.7% increase over the control Jiyujing. In 2003, the average yield of the production trial was 542.7 kg per mu, a 0.8% increase over the control Jiyujing.

Key cultivation techniques: 1. Cultivate strong seedlings: sow at the same time as Jiyujing according to local planting practices; for ordinary dry-raised seedlings, sow 150-200 g per sq m; 2. Transplanting: row spacing 30 cm, plant spacing 13.3-16.7 cm, with 3 grain seedlings per hill; 3. Fertilizer and water management: apply 45-50 kg of ammonium sulfate, 20-30 kg of superphosphate, and 10 kg of potassium sulfate per mu, together with a good application of farmyard manure. Water management should achieve shallow-water transplanting, shallow-moist tillering, field drying when sufficient seedlings are reached, shallow-water nurturing of the young panicle, shallow-moist heading, inch-deep water at flowering, and moist conditions for plump grains; 4. Pest and disease control: pay attention to controlling rice blast.

Approval opinion: Upon review, this variety meets the national rice variety approval standards and has passed approval. This variety matures relatively late, has medium yield, is susceptible to rice blast, and has excellent rice quality. It is suitable for planting in the upper limit of the first accumulated temperature zone in Heilongjiang, the medium-maturing rice region of Jilin Province, northeastern Liaoning, the Ningxia Yellow River irrigation area, and the rice blast-light-occurrence rice regions of southeastern Inner Mongolia and the Hexi Corridor of Gansu.