Key Cultivation Techniques for the Hybrid Indica Rice Yueyou 938

Yueyou 938 was approved and named by the Jiangsu Provincial Crop Variety Approval Committee in April 2000, and received national variety protection in May 2002. It is a three-line hybrid indica rice combination.

Breeding history: Yueyou 938 was developed jointly by the Institute of Atomic Energy for Agricultural Utilization and the Institute of Food Crops of the Jiangsu Academy of Agricultural Sciences. In the summer of 1993 in Nanjing, the red-lotus type high-quality three-line male sterile line Yuetai A was crossed with the red-lotus type restorer line r1005-8 to produce Yueyou 938. In 1994, this combination was tested in a small-plot variety comparison at the experimental field of the Institute of Food Crops of the Jiangsu Academy of Agricultural Sciences; the average yield over 3 replications was 9.28 t/hm2, 6.8% higher than the control Shanyou 63, reaching a significant level. In 1995, this combination was subjected to large-area demonstration and ecological adaptation trials at 11 sites in Jiangsu and Anhui, showing a relatively high level of yield increase.

Yield performance: In yield trials at various levels in Jiangsu from 1996 to 1998, Yueyou 938 generally had 2.32 million to 2.62 million effective panicles per hectare, a panicle-forming rate of about 60%, 180 to 190 total grains per panicle, a seed-setting rate of 80%, and a 1000-grain weight of about 27 grams. From 2000 to 2001, Yueyou 938 was demonstrated and planted in 10 provinces and regions including Jiangsu, Anhui, Henan, Hubei, Zhejiang, Fujian, Jiangxi, Hunan, Guangxi, and Sichuan, covering nearly 6700 hm2, with a usual yield of 9.7 to 10.5 t/hm2. In 2002, a total of 100,000 hm2 was demonstrated in the above provinces, with uniformly very good feedback. It is expected that 270,000 hm2 can be extended in 2003.

Characteristics: Yueyou 938 has a total leaf number of 17 to 18, a plant height of about 120 cm, and a general panicle length of 23.5 to 24.5 cm. Its tillering ability is moderate to strong, and its early seedling vigor is weaker than that of Shanyou 63. The plant type is compact, the leaves are narrow, long, and erect, and the leaf color is dark green. In the late growth stage, the functional leaves remain green and showy, with green stems and waxy stalks and good ripening color. According to quality analysis by the Rice and Rice Products Supervision and Testing Center of the Ministry of Agriculture, all quality traits of Yueyou 938 reached the grading standards of the National High-Quality Rice GB/T 17891-1999. Among the 12 indicators tested, 8 reached national grade 1 and 4 reached national grade 2, with an overall rating reaching the national grade 2 rice standard; in particular, the grain appearance quality and cooking quality are excellent. In 1997, according to identification by the Jiangsu Plant Protection Station, Yueyou 938 showed a resistance response of grade 3, that is, moderate resistance, to 4 rice bacterial blight strains, namely ks-6-6, Zhe 173, px079, and js49-6. It also showed moderate resistance to 3 rice blast pathogenic populations in the Yangtze River basin, za49, ze3, and zg1. By contrast, the control variety Shanyou 63 was susceptible to highly susceptible to the above bacterial blight strains. It was susceptible to the zg1 rice blast pathogen. When cultivated as single-season rice in Nanjing, sown in early May, the whole growth period is 147 to 150 days, about 7 days later in maturity than Shanyou 63. When cultivated as early rice in Guangzhou, the whole growth period is 137 to 140 days, 6 to 8 days later in maturity than Shanyou 63; when planted as late rice in Guangzhou, the whole growth period is 145 to 147 days, about 5 days later in maturity than Shanyou 63. After years of trials, this combination can be safely headed and matured and utilized in the Yangtze River basin, South China, and other single-season medium indica rice areas suitable for planting Shanyou 63.

High-yield cultivation techniques: Precision sowing and timely transplanting from April 25 to May 5, with chemical seed soaking treatment. The field seeding rate is 1.0 to 1.5 kg/667 m2, and the seedbed sowing rate should be controlled based on the standard that seedlings have 1 to 2 tillers at transplanting. Either dry-raised seedlings or wet-raised seedlings are acceptable. For dry-raised seedlings, the maximum seedling age should not exceed 50 days; for wet-raised seedlings, the maximum seedling age should not exceed 40 days. During the seedling stage, it is best to use growth regulators such as chlormequat for dwarfing treatment. Reasonable dense planting: the row spacing is 0.15 m x 0.21 m or 0.15 m x 0.24 m, with 15,000 to 17,000 hills per 667 m2 and 1 to 2 seedlings per hill. Pest and disease control: pest and disease control is generally carried out according to conventional hybrid indica rice practices, but rice false smut must be controlled.