Breeding and High-Yield Cultivation Techniques of the Rice Variety Lindao 12
1 Breeding history
In 1999, the Linyi City Rice Research Institute used radiation mutation breeding, treating 500 g of Yujing 6 seeds with 60Co alpha-rays at a dose of 40,000 roentgens, and planted the Mo generation that year; the population showed high sterility, and all seeds (M1 generation) were harvested in autumn; in the winter of the same year, winter multiplication in the south was carried out to add a generation, planting the M1 generation, and the population showed high segregation, and all M2 generation seeds were harvested. In 2000, the quartering bulk breeding method was used, planting the M2 generation, and in autumn 36 individual plants were selected as superior from the mutant population; in the winter of the same year, a second winter multiplication in the south was carried out, and the pedigree method was used to plant M3 seeds as individual plants, and 7 superior lines were selected and harvested separately. In 2001, a variety comparison trial was conducted at the institute, and in 2002 the in-house variety comparison trial continued. Through variety comparison, it was found that the third line had a growth period 3-5 days earlier than the control variety Yujing 6, strong tillering ability, high ear-bearing rate, uniform and consistent panicle layer, golden yellow color at maturity, extremely significant yield increase, excellent grain quality, fragrant and fresh taste, and outstanding comprehensive traits. In 2003, it was recommended to participate in the provincial rice regional trial, and in 2004 it continued the trial. In 2005, it participated in the provincial rice production trial. In April 2006, it passed the approval of the Shandong Provincial Crop Variety Approval Committee (approval number: Lu Nong Shen 2006038) and was named Lindao 12.
2 Variety characteristics
In the main rice areas of Shandong, the whole growth period of Lindao 12 is: 150 days for wet seedling raising and 156 days for dry seedling raising, belonging to a medium japonica medium-late maturing variety. Plant height is about 100 cm, plant type is compact, tillering ability is strong, flag leaves are erect, and the population has strong self-regulation ability. The panicle type is relatively large, with many grains, and the panicle layer is uniform and consistent; panicle length is 16 cm, effective panicles per mu are 249,000, ear-bearing rate is 73.2%, total grains per panicle are about 120, filled grains are about 95, seed setting rate is 79.2%, and 1000-grain weight is about 25 g.
In the regional trial, this variety showed slight susceptibility to seedling blast and neck blast, moderate resistance to sheath blight, stripe leaf blight, and rice false smut, and high resistance to bacterial leaf blight. In 2003, according to resistance identification by the Rice Research Institute of the Chinese Academy of Agricultural Sciences, this variety was moderately susceptible to seedling blast and neck blast, susceptible to bacterial leaf blight at the seedling stage, and moderately resistant at the adult plant stage. After years of variety comparison, regional trials, production trials, and production demonstration planting, this variety is relatively resistant to pests such as yellow stem borer, striped stem borer, rice leaf roller, and rice planthopper, and damage by rice thrips, rice leafhopper, and rice grasshopper is also relatively light.
In 2005, according to measurements by the Rice and Rice Products Quality Supervision and Inspection Testing Center of the Ministry of Agriculture (Hangzhou): the brown rice rate of this variety was 83.9%, milled rice rate 76.8%, head rice rate 73.8%, grain length 5.2 mm, length-width ratio 1.9, chalky grain rate 34%, chalkiness degree 4.9%, transparency grade 2, alkali spreading value 7.0, gel consistency 65 mm, amylose content 18.2%, and protein 10.2%.
3 Yield performance of the variety
In the in-house variety comparison trial from 2001 to 2002, the two-year average yield per mu was 575.8 kg, an increase of 12.1% over the control variety Yujing 6, reaching an extremely significant level.
From 2003 to 2004, it participated in the Shandong Provincial Rice Regional Trial, with a two-year average yield per mu of 503.1 kg, an increase of 8.1% over the control Yujing 6.
In 2005, it participated in the Shandong Provincial Rice Production Trial, with an average yield per mu of 508.54 kg, an increase of 2.6% over the control Yujing 6, ranking second.
4 High-yield cultivation techniques
Lindao 12 is suitable for promotion and planting as wheat-stubble rice in the reservoir-irrigated rice area of southern Shandong and the lakeside rice area of southwestern Shandong, and can also be planted as wheat-stubble rice in northern Jiangsu and the central Henan areas suitable for Yujing 6, as well as for demonstration planting as spring rice in northern Shandong. It is recommended for demonstration and application as a main selected variety for producing high-quality rice and organic rice.
4.1 Sparse seeding and strong seedling cultivation: Whether dry seedling raising or wet seedling raising is used, the seed rate per mu of field is generally 3.0-3.5 kg, and no more than 4 kg at most. Before sowing in the seedling field, use Shibaike or Exianqing and soak the seeds for 5-7 days to prevent bakanae disease, rice false smut, nematodes, and others. For pre-emergence weed control in the seedling field, generally use 0.3 kg of oxadiazon and 0.3 kg of butachlor per mu, mixed with 60 kg of water (increase the amount of water when the soil is dry) and spray evenly to form a chemical soil surface barrier; for post-emergence weed control, generally at the two-leaf stage of barnyardgrass, use 1 kg of propanil per mu, divided over two days and two applications, each mixed with 60 kg of water and sprayed, or use a mixture of bensulfuron-methyl and Daonongle mixed with 60 kg of water and sprayed for weed control.
4.2 Rational fertilization, controlling nitrogen and increasing potassium: Grasp the principle of heavy application early and light application later, and a "one-time application" can also be used. For field basal fertilizer, apply 50 kg of ammonium bicarbonate or 17.5-20 kg of urea per mu, together with 15 kg of diammonium phosphate, 15 kg of potassium fertilizer, and 2 kg of zinc fertilizer; alternatively, apply 60-75 kg of ternary compound fertilizer per mu, together with 2 kg of zinc fertilizer. Topdressing is divided into two applications: 5-7 days after transplanting, apply 7.5 kg of urea per mu as tillering fertilizer; at the early stage of jointing and booting (around July 20), apply 5 kg of urea and 10 kg of potassium fertilizer per mu. During the entire field period, the pure nitrogen applied per mu should not exceed 19 kg. In the middle and late field stages, apply as little nitrogen fertilizer as possible or none, to prevent excessive nitrogen fertilizer causing delayed maturity with excessive vegetative growth. For foliar fertilizer in the later stage, spray foliar fertilizers such as potassium dihydrogen phosphate and Zhuangduoshou Yeba in early September to promote full grain filling.
4.3 Rational close planting and early prevention of pests and diseases: This variety has strong tillering ability, so row spacing should be widened, using wide and narrow row planting, with wide rows of 30-40 cm, narrow rows of 15-20 cm, hill spacing of 10-12 cm, and 2-3 seedlings per hill; never exceed 3 seedlings. Pests and diseases should be mainly prevented, with early prevention and early treatment.
Three pesticide applications in the seedling field: The first, after the 3-leaf stage, use omethoate, imidacloprid, and others to kill small brown planthopper and prevent stripe leaf blight; the second, 1-3 days before wheat harvest, use methamidophos to control small brown planthopper, thrips, and stem borers; the third, 1-2 days before transplanting, spray once more with methamidophos to control overwintering-generation stem borers (yellow stem borer).
Three pesticide applications in the field: The first, around July 20, spray validamycin, methamidophos, and others to control sheath blight and first-generation stem borers; the second and third, in mid and late August, that is, before and after heading, spray once each, focusing on controlling neck blast, bacterial leaf blight, rice leaf roller, rice planthopper, and other pests and diseases.
4.4 Rational irrigation and timely field drying: Use shallow water for seedling establishment and thin water for tillering; after greening, maintain alternating wet and dry conditions; when enough tillers are reached, dry the field in a timely manner to control ineffective tillering; especially in the middle and late stages, do not keep deep water for a long time, so that pests and diseases are lighter, plants are robust, grain filling and maturity are sufficient, grains are plump, and high and stable yield is achieved.