Introduction to the Characteristics of Rice Variety D You 68

Breeding units: Rice Research Institute of Sichuan Agricultural University, and Neijiang Hybrid Rice Center of Sichuan Province.

Approval status: approved by the Sichuan Provincial Crop Variety Approval Committee in 1997, and by the National Crop Variety Approval Committee, the Shaanxi Provincial Crop Variety Approval Committee, and the Henan Provincial Crop Variety Approval Committee in 2000.

Variety approval number: Guoshen Dao 20000002.

Variety source: D62A/Duoxi No. 1.

Characteristics: a medium indica late-maturing three-line hybrid rice. Plant height 114.3 cm, plant type relatively compact, good luxuriance, panicle length 23.7 cm, effective panicles per mu 200,000, grains per panicle 135.6, seed setting rate 79.6%, 1000-grain weight 26.7 g. Good color change at late stage, relatively high yield, good yield stability. Head rice rate 54.3%, chalkiness 10.5%, amylose content 20.2%, relatively good appearance and grain quality. The whole growth period is about 147 days, 4.7 days later than the control Shanyou 63. Moderately susceptible to rice blast, highly susceptible to bacterial leaf blight, relatively good grain quality. In 1997 it participated in the national indica hybrid rice regional trial, with an average yield of 563.83 kg per mu, 0.85% higher than the control Shanyou 63; in 1998 it participated in the southern rice region medium indica late-maturing group regional trial, with an average yield of 510.41 kg per mu, 0.9% higher than the control Shanyou 63; in 1999 the average yield in the production test was 568.81 kg per mu, 1.58% higher than the control Shanyou 63.

Cultivation points: sow at the proper time, sow thinly to raise strong seedlings. The sowing rate per mu of seedling field should be controlled at about 10 kg, and the seedling age is generally best at about 45 days. Transplanting at 1.4 ten-thousand hills per mu is appropriate, ensuring more than 60,000 basic seedlings per mu. Base fertilizer should be dominant, with topdressing as a supplement, and increase the application of phosphorus and potassium fertilizers. Manage flowering period regulation well. For seed production in Sichuan Province, the male parent Duoxi No. 1 is generally sown around April 1 and begins heading on July 25-28; the female parent D62A is sown around May 1 and begins heading on July 25-28, so the flowering periods meet well. D62A has a relatively large panicle type and a high outcrossing rate; when producing seed for Duoxi No. 1, whose heading is relatively concentrated, it is suitable to have the female parent begin heading 1-2 days earlier than the male parent. Manage field management well and apply "920" properly. D62A has relatively light panicle enclosure and the main panicle heads early; when applying "920", first, it should be concentrated, and second, the amount should be relatively small. That is, apply the first dose when 25%-35% of the female parent has headed, and apply the second dose the next day, with the total amount of "920" controlled at 12-15 g. D62A has a high stigma exsertion rate, so special attention must be paid to controlling rice false smut during propagation and seed production.

Suitable range: planted as single-season medium rice in the light-occurrence areas of bacterial leaf blight in the southwest, the Yangtze River basin, and southern Henan and Shaanxi provinces.