Key Cultivation Techniques for the Two-Line Hybrid Japonica Rice Wandao 48

To meet the demand of the high-quality japonica rice market, the Rice Research Institute of the Anhui Academy of Agricultural Sciences developed the high-quality two-line japonica hybrid combination Wandao 48 (also known as 70 You Shuang Jiu) by crossing 7001S with 2277. Through experimental demonstration and grain quality evaluation, it has shown high quality, high yield, and multi-resistance.

1 Characteristics and Traits

It belongs to the early-maturing late japonica type, with a whole growth period of 128 days (double-cropping late rice) to 140 days (single-cropping late rice). Plant height is 93 cm. Plant type is moderately compact. Leaf color is light green. Main stem has 15 to 17 leaves. Panicle is umbrella-shaped. Panicle length is 19.8 cm, with more than 110 total grains per panicle and a seed-setting rate of 85%. Grains are oval. Awnless. Hull is thin and light yellow. 1000-grain weight is 24 to 26 g. Strong photoperiod sensitivity. Requires above-medium fertility. Strong tillering ability and high productive tiller rate. Fast grain filling and good color retention at maturity. Relatively easy to thresh. Tolerant to low temperatures. According to artificial inoculation identification by the Plant Protection Institute of the Anhui Academy of Agricultural Sciences, it is moderately resistant to rice blast (grade 3) and bacterial leaf blight (grade 3). Brown rice rate 83.1%, milled rice rate 75.3%. Head rice rate 74.0%, grain length 5.3 mm, length-to-width ratio 1.9; chalky grain rate 7%, chalkiness degree 0.9%, transparency grade 1. Gelatinization temperature is low (grade 6.9), gel consistency is soft (80 mm), amylose content 18%, protein 9.3%. Good eating quality. Good grain elongation.

2 Yield Performance

In 1995, a trial planting of 0.33 hm2 in Lujiang County, Anhui Province, yielded 7.5 t/hm2, a 15.4% increase over the control Xiushui 664. In 1996, a trial planting of 6.67 hm2 at Baihu Farm yielded 8.58 t/hm2. In 1997, in the production trial of new japonica hybrid combinations, the yield was 6.75 t/hm2, a 14.8% increase over the control Xiushui 664; a 2.14% decrease compared with 70 You 04 (two-line japonica hybrid), but the difference was not significant. In the same year, a demonstration planting of 0.67 hm2 in Xindu Township, Lujiang County, yielded 6.43 t/hm2, with the highest reaching 8.21 t/hm2, a 19.2% increase over the main planted variety Xiushui 664. In 1998, 533 hm2 were planted, with yields of 6.75 to 7.50 t/hm2, about a 15% increase over the main planted conventional varieties.

3 Main Cultivation Techniques

Timely sowing and cultivation of strong multi-tiller seedlings: Sun the seed for 1 to 2 days before sowing, then soak in clean water for 24 hours, and then soak in a 500-fold strong chlorine disinfectant solution for 12 hours to prevent bakanae disease and rice false smut. After 90% of the seeds have broken their hulls during germination, air-dry the sprouts and sow. For rapeseed stubble, sow in early May; when following watermelon stubble as single-cropping rice, sow from late May to early June, with a seedling age of 30 to 35 days; for double-cropping late rice, sow around June 20 and transplant in late July, with a seedling age of 35 to 40 days. To cultivate strong seedlings with 2 to 3 large tillers, first, sow 150.0 to 187.6 kg/hm2 in a clean seedling field, and strictly control the ratio of seedling field to main field at 1:6. Second, spray paclobutrazol: from the 1-leaf-1-heart to 3-leaf-1-heart stage, spray 3.00 to 3.75 kg of paclobutrazol per hectare diluted in water to promote dwarfing and increase tillering while also controlling weeds. Third, promptly control rice thrips.

Wide-row narrow-plant double-seedling transplanting: This transplanting method not only improves air and light penetration in the middle and late stages, but also has a certain seedling-control effect after the peak tillering stage, resulting in fewer ineffective tillers, a high productive tiller rate, and an obvious yield-increasing effect. Plant-row spacing is 10 cm x 27 cm for single-cropping late rice and 10 cm x 23.3 cm for double-cropping late rice; planting density is 375,000 (single) to 350,000 (double) hills/hm2. Plant 2 seeds per hill, transplanting 1.5 to 2.25 million basic stem-tiller seedlings per hectare, striving to reach a maximum of 4.5 million/hm2 and ensuring 3.5 million productive panicles/hm2.

Scientific fertilization: In view of its characteristics of large low-position tiller panicles, high productive tiller rate, and relatively large differences in panicle type among tiller positions, which are conducive to promoting early development in the main field and focusing on low-position tillers in the seedling field, fertilizer management should follow the principle for single-cropping late rice of promoting stable development and stable growth in the early stage, strengthening stems and stalks in the middle stage, and applying an appropriate amount of supplementary fertilizer in the late stage. Apply 180 to 225 kg of pure nitrogen per hectare in the main field, of which basal fertilizer and tillering fertilizer account for about 60% of the total, including 50% organic fertilizer, combined with phosphorus and potassium fertilizer. For double-cropping late rice, follow the "four main and one supplement" fertilization principle, that is, mainly basal fertilizer, organic fertilizer, tillering fertilizer, and quick-acting fertilizer, with an appropriate supplementary application of grain fertilizer after full heading, so as to achieve early sufficient seedlings, strive for large panicles, and increase the seed-setting rate and grain weight. Apply 150 to 180 kg of pure nitrogen per hectare in the main field, of which basal and tillering fertilizer account for 80% of the total. Topdressing should be early; otherwise ineffective tillers will increase, causing the field to become too dense. For grain fertilizer, applying 30 to 40 kg/hm2 of urea is sufficient.

Water management: During the effective tillering stage, irrigate frequently with shallow water to promote tillering; at the end of tillering, drain the field in time and "bake the field well" to control ineffective tillers and favor strong stems and stalks for developing large panicles. Also, because its grain-filling period is long, attention should be paid in the late stage to maintaining the rice plants for good grain filling. It is better to stop irrigation 5 to 7 days before harvest. Harvest later than ordinary conventional late japonica rice. Promptly control bacterial leaf blight, rice false smut, sheath blight caused by Sclerotium hydrophilum, and rice planthopper damage to ensure a bumper harvest.