Introduction to the new late japonica rice variety Jia 991

Jia 991 was approved in March 2003 at the 27th variety approval meeting of the Provincial Agricultural Crop Variety Approval Committee. In the 2000 and 2001 Jiaxing municipal trials, the average yields per mu were 537.2 kg and 563.7 kg respectively, a decrease of 4.38% and an increase of 3.19% compared with the control Xiushui 63 (both differences not significant), with a two-year average decrease of 0.60% compared with the control. The two-year average whole growth period was 158.5 days, the same as the control Xiushui 63. In the 2002 municipal production trial, the average yield per mu was 563.03 kg, an increase of 2.33% compared with the control Xiushui 63. In the two-year municipal trials, the average number of effective panicles was 233,000, total grains per panicle 108.9, seed setting rate 89.3%, and 1000-grain weight 26.8 g. According to identification by the Institute of Plant Protection of the Provincial Academy of Agricultural Sciences, it is moderately resistant to rice blast and bacterial leaf blight, susceptible to narrow brown leaf spot, brown planthopper and white-backed planthopper. According to analysis by the Rice and Rice Products Quality Supervision, Inspection and Testing Center of the Ministry of Agriculture, eleven indicators including brown rice rate, milled rice rate, head rice rate, grain length, length-width ratio, chalkiness degree, transparency, alkali spreading value, gel consistency, amylose content and protein content reached the ministerial first-grade standard for high-quality rice. This variety is a dense-panicle type with a moderate growth period, stout stems, medium tillering ability and relatively large panicles; its grain quality is clearly superior to Xiushui 63, its yield performance is good, and its resistance to rice blast is better than Xiushui 63. It is suitable for cultivation as transplanted late rice in northern Zhejiang.

Key points of cultivation techniques:

1. Sow thinly and early at the right time, with a sowing rate of 30-35 kg per mu and a seedling age of about 30 days.

2. Transplant at the right seedling age and plant at a reasonable density: transplanting at the right seedling age promotes early growth, and reasonable dense planting increases the number of panicles. Plant about 25,000 hills per mu, with 60,000-80,000 seedlings per mu in the field.

3. Coordinate fertilization: apply sufficient organic fertilizer, with the total fertilizer amount over the whole growth period equivalent to 25-30 kg of urea, together with phosphorus and potassium fertilizer; the fertilization method should be heavy at the front and controlled at the back, reducing the amount of nitrogen in the later stage. On the basis of good early development and a well-established framework, no nitrogen fertilizer should be applied after mid-July for single-season rice and after early August for continuous cropping late rice, so as to increase the seed setting rate and 1000-grain weight and achieve high yield and high quality.

4. Scientific water management. Alternate wetting and drying in the middle and late stages to strengthen roots and tillers; avoid stopping water too early in the late stage, and attention should be paid to control in areas where rice blast occurs heavily.