Characteristics and Traits of the Rice Variety Huayou Gui 99
[Basic Information] The promotion of hybrid rice has played an important role in increasing China's grain production. With the development of the national economy and the continuous improvement of people's living standards, the requirements for grain quality have become increasingly higher. Breeding early indica hybrid rice combinations with good quality, high yield, and disease resistance is an important issue urgently needing to be solved in current rice breeding. The Department of Agronomy of South China Agricultural University, in collaboration with Tengxian Seed Company and Raoping County Seed Company, used the high-quality male sterile line Y Huanong A, which is highly resistant to rice blast, and the restorer line Gui 99 to develop the new high-quality, high-yield, rice blast-resistant South China early indica hybrid rice combination Huayou Gui 99.
[Characteristics and Traits] In the Guangdong provincial regional trial, the appearance of Huayou Gui 99 early-season rice was graded as second class. The analysis results of the physicochemical properties of Huayou Gui 99 early- and late-season rice by the Rice and Rice Products Quality Supervision and Inspection Testing Center of the Ministry of Agriculture were as follows: early season milled rice rate 73.1%, chalkiness degree 3.4%, alkali spreading value grade 5.1, amylose content 20.1%, protein content 9.9%, and these 5 indicators reached the Ministry-issued first-class standard for high-quality rice; brown rice rate 80.6%, head milled rice rate 58.6%, grain length 5.8mm, length-to-width ratio 2.9, transparency grade 2, gel consistency 51mm, and these 6 indicators reached the Ministry-issued second-class standard for high-quality rice, with an overall score of 57 points. For the late season, the average of 3 samples from different production sites was: milled rice rate 74.5%, head milled rice rate 68.6%, chalkiness degree 1.3%, alkali spreading value 6.5, amylose content 21.1%, protein content 10.0%, and these 6 indicators reached the Ministry-issued first-class standard for high-quality rice; brown rice rate 80.3%, grain length 6.1mm, length-to-width ratio 2.8, transparency grade 2, gel consistency 40.3mm, and these 5 indicators reached the Ministry-issued second-class standard for high-quality rice. Only the chalky grain rate (19% in early season, 11.7% in late season) failed to meet the standard. In addition, according to feedback from growers in the planting areas, Huayou Gui 99 has a rich rice flavor with a slight delicate fragrance, and the cooked rice is smooth and refreshing with moderate hardness and softness; cooked dry rice is soft but not sticky, and congee is thick but not pasty. It is a new combination with excellent grain quality among current early indica hybrid rice.
Huayou Gui 99 participated in the late-maturing group regional trial in Guangdong Province in the early seasons of 1999 and 2000. The average yield per unit area in the first trial across 14 sites was 7.02 t/hm2, 0.9% lower than the control combination Shanyou 63; in the continued trial it was 7.53 t/hm2, 2.7% and 2.6% higher than the control combinations Shanyou 63 and Peiza Shuangqi respectively; the increases and decreases were not significant. In the 2-year, 4-season variety comparison at the Raoping County Agricultural Science Institute, the average yield per unit area was 6.39 t/hm2, 2.2% higher than Peiza Shuangqi; in the 2000 early-season variety comparisons in Qingyuan, Yangchun, Xinyi and other cities, the average yield per unit area was 7.00-8.47 t/hm2, 1.3%-12.4% higher than Peiza Shuangqi. In the 1999 early season, Huayou Gui 99 participated in the new variety screening trial in Guangxi Zhuang Autonomous Region, with an average yield per unit area of 7.27 t/hm2 across 3 sites, 3.9% lower than Shanyou Gui 99; in the variety comparison at the Guangxi Original Seed Farm, the average yield per unit area was 8.24 t/hm2, 3.7% higher than Teyou 63. In the 2000 early-season regional trial in Yulin City, the average yield per unit area of Huayou Gui 99 across 6 trial sites was 8.14 t/hm2, 8.7% higher than Teyou 63.
Huayou Gui 99 was trial-planted on about 1700 hm2 in various places in Guangdong. Among this, Raoping County had 167 hm2, with yields generally 7.50 t/hm2 and high-yield cultivation exceeding 9.00 t/hm2. After 4 consecutive seasons of multi-site trials in areas with different ecological types, the average yield per unit area was 7.71-8.07 t/hm2 in the early season, 5.2%-7.9% higher than Peiza Shuangqi, and 6.92-7.91 t/hm2 in the late season, 4.6%-6.5% higher than Peiza Shuangqi and 1.4% lower than II You 3550; Jieyang City had 1020 hm2, with yields of 6.75-8.25 t/hm2. In Guangxi Zhuang Autonomous Region, Huayou Gui 99 was trial-planted on a total of 3133 hm2. Among this, Tengxian had 2167 hm2, with yields of 7.75-10.45 t/hm2 in the early season and 7.33-9.19 t/hm2 in the late season; the counties in eastern Guangxi trial-planted 967 hm2, with yields of 7.38-8.75 t/hm2, about 0.60 t/hm2 higher than Shanyou Gui 99. By 2000, Huayou Gui 99 had been trial-planted on about 5700 hm2 in Guangdong and Guangxi, with yields comparable to currently promoted high-yield combinations and a relatively large yield increase over high-quality combinations. Growers consider Huayou Gui 99 to be a new combination with "good quality, high yield, and good resistance," and some cities and counties have already listed it for the development and utilization of high-quality rice.
The Guangdong Provincial Crop Disease and Insect Forecasting Station conducted unified disease resistance identification of the combinations participating in the regional trial. Huayou Gui 99 is highly resistant to rice blast, with 100% resistance to the whole group under inoculation conditions lacking the Zhong A group, and basically no disease occurred in field monitoring (including the Yangjiang site where the Zhong A group is the dominant population); it is moderately susceptible to bacterial blight, with an overall resistance rating of grade 5.
[Breeders] Department of Agronomy, South China Agricultural University, Tengxian Seed Company, and Raoping County Seed Company
[Regions and Techniques] Huayou Gui 99 was trial-planted in Guangdong and Guangxi. Its whole growth period is 123-131 d in the early season, 2-5 d earlier than Shanyou 63 and Teyou 63, and about 115 d in the late season, similar to Peiza Shuangqi and Shanyou 46. In areas and seasons suitable for Shanyou 63 and Shanyou 46, it can be introduced for trial planting and promotion.
Huayou Gui 99 has no purple color on the leaf sheath, leaf margin, stem node, stalk tip, or stigma; it has vigorous growth, strong tillering ability, a relatively concentrated plant type, medium leaves, clean and elegant leaf color, uniform heading, and green branches and waxy stalks at maturity; plant height 100-105 cm, effective panicles 2.70 million-3.00 million/hm2, panicle length about 23 cm, 130-150 grains per panicle, seed-setting rate 80%-90%, and 1000-grain weight about 23 g.
The growth period difference between Y Huanong A and the restorer line is relatively small, making it easy to adjust the sowing and planting dates of the parents during seed production to achieve flowering-stage synchronization; its flowering habits are good, and seed production yields are high. In the 1999 late season, Tengxian Seed Company carried out the first large-scale production of Huayou Gui 99 on 8.2 hm2, with an average yield per unit area of 3.02 t/hm2.
Sow and plant early at the appropriate time. For Huayou Gui 99, the sowing and planting dates in the early, middle, and late seasons can all refer to those of combinations such as Shanyou 63, Teyou 63, and Peiza Shuangqi. Late-season planting should be controlled so that full heading occurs within the safe full-heading period, so as not to affect heading uniformity, seed-setting rate, and grain filling. Rational close planting and transplanting two seedlings per hill should be used to increase the number of panicles. Apply sufficient base fertilizer, apply tillering fertilizer early, increase phosphorus and potassium fertilizer, control nitrogen in the middle stage, and apply a supplementary tail-strengthening fertilizer later according to crop condition, striving for more panicles and large panicles. Prevent heavy nitrogen application in the middle stage from delaying the growth period, causing field shading, and affecting seed setting. Keep shallow water for greening, thin water for tillering, drain the field when enough tillers have been reached, shallow water for heading, and alternate dry and wet conditions for maturity. Do not cut off water too early, so as to improve the seed-setting rate and grain filling. Pay attention to disease and insect forecasting to prevent pest outbreaks and ensure a bumper harvest.
Seed production of Huayou Gui 99 is relatively easy, and the technical measures are similar to those for general combinations. The main point is to regulate the sowing and planting interval between the parents to ensure flowering-stage synchronization. Under normal weather conditions, the sowing interval between Y Huanong A and Gui 99 is about a 4-leaf difference in the early season and a 3-5 d time difference in the late season.