Detailed Introduction to Rice Variety K You 5

Breeding institution: Rice and Sorghum Research Institute, Sichuan Academy of Agricultural Sciences.

Approval status: approved by the Sichuan Provincial Crop Variety Approval Committee in 1996, by the Guizhou Provincial Crop Variety Approval Committee in 1998, and by the National Crop Variety Approval Committee in 1999.

Variety approval number: Guoshendao 9900ll.

Variety source: K17AX Duohui 1.

Characteristics: a three-line hybrid rice medium indica late-maturing combination. Plant height 110-115 cm, vigorous growth at the seedling stage, compact plant type, ligule and leaf margins both colored, total leaf number on the main stem 16. Tillering ability medium to high, maximum number of seedlings about 270,000 per mu. Effective panicles about 180,000 per mu. Panicle spindle-shaped, panicle length dui cm, grains per panicle 130-140, seed setting rate 85%, uniform heading, good color conversion at the late stage. Grains yellow, apiculus colored, oblong, a small amount of awn on the tip. 1000-grain weight 28-30 g, brown rice rate 80%, milled rice rate 70%, good transparency, rice quality medium to upper grade, good yield potential. Whole growth period 144 days, on average 2 days earlier maturing than Shanyou 63. Moderately susceptible to bacterial leaf blight, moderately resistant to rice blast. In the 1995-1996 Southern Rice Region regional trials, average yield was 574.13 kg and 539.33 kg per mu, an increase of 3.57% and 4.93% respectively over the control Shanyou 63.

Cultivation points: the sowing period in the Southern Rice Region is the same as that of Shanyou 63; a seedling age of 30-35 days is suitable, with a seeding rate of 1.25-1.5 kg per mu of paddy field; transplanting spacing 26.6 cm x 16.7 cm, 2 seedlings per hill; apply sufficient base fertilizer before transplanting, generally 8-10 kg of pure nitrogen, 25 kg of calcium superphosphate, and 100 kg of plant ash per mu, and apply 2-3 kg of topdressing per mu 7-10 days after transplanting. K17A has a high stigma exsertion rate and good outcrossing habits, therefore strict isolation is required in both multiplication and seed production. K17A has light panicle enclosure and is sensitive to gibberellin; its "920" dosage is 70% of that for Shanyou combinations, and when 10%-15% of panicles have headed, lightly cut the leaves and spray twice, with the dosage per mu strictly controlled within 12 g. Strictly remove off-types, and this should be done at the initial heading stage.

Suitable range: Sichuan, Chongqing, Guizhou Province, and areas of the same ecological type for cultivation as medium rice.