Comparative Test of New Late Indica Hybrid Rice Combinations with Good Quality

Jinhe HU Fei ZHU Xiaolin CHENG Yuping HU Fengqin YU

Abstract [Objectives] This study was conducted to screen rice varieties suitable for planting in Nanchang City with high quality， high yield， good yield， and strong disease and stress resistance.

[Methods]Seven new late indica hybrid rice combinations with good quality bred in Jiangxi Province in recent years and seven new late indica hybrid rice combinations with good quality bred by Nanchang Academy of Agricultural Sciences were introduced， and compared with Tianyouhuazhan as a control.

[Results] The rice quality and taste of the tested combinations were better than those of the control. Among the tested combinations， Yuliangyoufuxiangzhan， Xintaiyousizhan， Yuxiangliangyou No.8 and Guangheyou 33 had good stress resistance， high yield and good rice quality.

[Conclusions]This study provides a theoretical basis for the selection and breeding of new rice varieties in Nanchang City.

Key words Good-quality late indica rice; Hybrid rice; New combination; Comparative test

Received： March 3， 2021  Accepted： May 5， 2021

Supported by Demonstration of Green and High-efficiency Cultivation Techniques for High-quality Rice （GCJ[2011]250）.

Jinhe HU （1963-）， male， P. R. China， researcher， devoted to research about rice breeding.

*Corresponding author.

The No.1 Central Document of 2019 pointed out that "We should stabilize grain production. We will not relax in grain production， and will promote the implementation of storing grains by land and technologies， ensuring that the grain sown area is stabilized at 110 million hectares"[1]. "We should adjust and optimize the agricultural structure. We will vigorously develop the production of scarce and green high-quality agricultural products， promote the transformation of agriculture from an increase in production orientation to an improvement in quality orientation， and further advance the high-quality grain project."[1]

In order to adapt to the adjustment of the agricultural supply-side structure， we should improve the quality and safety of rice in Nanchang City， improve farmers rice planting technology， improve rice planting efficiency， increase farmers income， and meet peoples requirements for a better life， while ensuring rice production. Vigorously introducing， breeding， demonstrating and popularizing new high-quality rice varieties can provide technical support for improving the quality and efficiency of rice production in Nanchang City. For this reason， in 2020， Nanchang Academy of Agricultural Sciences introduced new high-quality late indica hybrid rice combinations selected in Jiangxi Province in recent years and new high-quality late indica hybrid rice combinations selected by Nanchang Academy of Agricultural Sciences， and carried out  a simple comparative test in the Henghu Modern Agricultural Science and Technology Park of Nanchang Academy of Agricultural Sciences， so as to screen out rice varieties with high quality， high yield， good yield， and strong disease and stress resistance suitable for planting in Nanchang City.

Materials and Methods

Tested varieties

A total of seven new high-quality late indica hybrid rice combinations bred in Jiangxi Province in recent years and seven new high-quality late indica hybrid rice combinations bred by Nanchang Academy of Agricultural Sciences were introduced in this experiment， and with the mid-maturing combination Tianyouhuazhanhe and the early-maturing combination Wuyou 308 as controls， a simple comparative test was carried out （Table 1）.

Plot design

The test site was Henghu Modern Agricultural Science and Technology Park of Nanchang Academy of Agricultural Sciences. The test was carried out in the same field， surrounded by protection rows. Random arrangement was adopted without duplication. Each combination was planted with 333.3 m and the planting specification was 20 cm×16.7 cm. The planting density was 300 000 hills/hm 2 seedlings per hill， and there was a work row between various combinations.

Test process

According to the local late rice cultivation method， seeds were soaked on June 18 to accelerate germination， sown on June 20， artificially transplanted on July 15， and harvested by machine after maturity for yield monitoring. The experimental field had alluvial loam with medium fertility. Field management was in accordance with the local common methods. In terms of fertilization， 45% compound fertilizer （15-15-15） 4 500 kg/hm2 was applied as the base fertilizer， urea 112.5 kg/hm2 and potassium fertilizer 45 kg/hm2 were applied as the tillering fertilizer， and urea 75 kg/hm2 and potassium fertilizer 75 kg/hm2 were applied as the panicle fertilizer. The prevention and control of diseases， pests and weeds was implemented according to general field production technology. The main growth period and growth performance as well as the situation of diseases and pests were recorded. At the maturation stage， 5 plants were selected from each material to investigate its agronomic and quality traits.

Results and Analysis

Performance of various combinations during their growth period

From the results in Table  it can be seen that the growth periods of all varieties in this experiment were between 121 and 127 d. Due to the early cold dew wind in Nanchang this year and the long duration of low temperature weather， the growth period was prolonged. Among the various varieties， the control combination Tianyouhuazhan had the longest growth period of 127 d. The full growth periods of Yujingyou 033， Yujingyou 50， Xintaiyousizhan， Yexiangyoulisi， Yuliangyoufuxiangzhan， Taixiangyouyuehesimiao， and Leiyou 106 were all between 123 and 125 d， 2-4 d shorter than the mid-maturing control combination Tianyouhuazhan， and 1-3 d longer than the early-maturing control combination Wuyou 308. The full growth periods of Guangheyou 33， 7375 You 1904， Yuxiangliangyou No.8， Yueheyou 202 Yexiangyouliangzhan， Taiyouxiangzhan， Ruanhuayouyuzhu and other combinations were all between 121 and 122 d， 1 d shorter than or equal to the early-maturing control combination Wuyou 308， so they were early-maturing combinations （Table 2）.

Main agronomic traits and yield components of various combinations

The results in Table 3 showed that the plant heights of various combinations were between 102.8 and 117.8 cm. Yujingyou 50 exhibited the largest plant height of 117.8 cm， while the plant height of Taixiangyouyuehesimiao was the smallest at 102.8 cm. The effective panicles were between 2.745 and 3.645 million panicles/hm2. 7375 You 1904 and Yuxiangliangyou 8 had more effective panicles of 3.48 and 3.735 million panicles/hm respectively; and Yujingyou 50 and Ruanhuayouyu had fewer panicles， 2.745 and 2.895 million panicles/hm respectively. The numbers of filled grains per panicle for various combinations were in the range of 107.4-134.1 grains. Leiyou 1068 and Yuliangyoufuxiang had more filled grains per panicle， 134.1 and 131.4 grains， respectively， and the field performance was large panicles， small grains and high density of grains. Yueheyou 2021 and Yuxiangliangyou No.8 had fewer filled grains per panicle， 107.4 and 113.9， respectively. The seed setting rates of various varieties were between 74.2% and 80.6%. Except for Taixiangyouyuehesimiao and Yuxiangliangyou No.8 showing seed setting rates of 81.75% and 80.6%， respectively， the values of other combinations were all lower than 80%， mostly 76%， which was mainly because the cold dew came early in the later period， under the effects of the low temperature and rain， the seed setting rates were generally lower， and the grain plumpness was poor （Table 3）.

Yield results

The results in Table 4 showed that the early-maturing combination Yuxiangliangyou No.8 had the highest yield of 8 204.7 kg/hm followed by Guangheyou 33 with a yield of 8 155.5 kg/hm and the next ones Taiyouxiangzhan， Ruanhuayouyuzhu， 737 You 1904 and Yexiangyouliangzhan， the yields of which were 7 934， 7 840.5， 7 819.5 and 7 771.5 kg/hm respectively. Their yields increased by 6.84%， 6.19%， 3.31%， 2.02%， 1.86% and 1.20% compared with the control Wuyou 308， respectively. The yield of Yueheyou 2021 was the lowest in hectares， and reduced by -2.40% compared with the control Wuyou 308. For the mid-maturity combinations， Yuliangyoufuxiangzhan had the highest yield of 8 296.5 kg/hm followed by Xintaiyousizhan with a yield of 8 250 kg/hm and the third was Yexiangyoulisi with a yield of 8 230.5 kg/hm followed by Taixiangyouyuehesimiao， the yield of which was 8 169 kg/hm2. The yields of the four increased by 2.53%， 19.6%， 1.72% and 0.96% compared with the control Tianyouhuazhan， respectively. The yields of other combinations decreased by -0.15%-1.96% compared with the control Tianyouhuazhan （Table 4）.

Rice quality performance

The results in Table 5 showed that the tested varieties were all high-quality rice， reaching level 3 or above， and the two control varieties are ordinary rice. Among the tested combinations， Yuliangyoufuxiangzhan reached level 1 according to the ministry standards and had fragrance; nine combinations， Xintaiyousizhan， Leiyou 1068， Yujingyou 50， Yexiangyoulisi， Yujingyou 033， Taiyouxiangzhan， Ruanhuayouyuzhu， Yexiangyouliangzhan， and Yuxiangliangyou No.8， reached level 2 according to the ministry standards; and other combinations reached level 3 according to the ministry standards.

Resistance performance

The results in Table 6 showed that Guangheyou 33 had the best resistance， with neck blast of grade 5 and moderate resistance to rice blast. The second was Yujingyou 033， which showed neck blast of grade 7 and was susceptible to rice blast. Other combinations exhibited neck blast of grade 9 and were susceptible to rice blast. According to the comprehensive index of rice blast， the values of early-maturing combinations were in the range of 2.6-4.6， better than the control Wuyou 308 at 5.4. For the late-maturing combinations， the comprehensive index of rice blast was the lowest in Taixiangyouyuehesimiao at 2.9， followed by Yuliangyoufuxiangzhan and Yujingyou 50 at 3.0， and Jianyou 1068 at 3. and all were lower than the control Tianyouhuazhan at 4.3. Other combinations were the same as the control.

Summary of main varieties

Under the experimental conditions， combining the characteristics， yield， rice quality and resistance of each combination， we believed that， except for Yueheyou 2021 and Yujingyou 033 which were worse than the control， other combinations were better than the control and were suitable for planting in Nanchang. Among them， Yuxiangliangyou No.8， Guangheyou 33， Yuliangyou Fuxiangzhan， Xintaiyousizhan， Yuxiangliangyou No.8， Guangheyou 33 and other combinations had good stress resistance， high yield and excellent rice quality. Their combination characteristics were as blow.

① Yuxiangliangyou No.8 had a full growth period of 121 d and matured 1 d earlier than the control Wuyou 308. The combination plants were short， lodging resistant， and had moderate plant type， straight flag leaves， luxuriant growth， strong tillering ability， many effective panicles， colorless palea tips， high seed setting rate， small 1 000-grain weight， and medium color change at the maturation stage. It showed a plant height of 104.4 cm， effective panicles of 3.735 million panicles/hm a total number of grains per panicle of 139.3 grains， a number of filled grains of 113.9 grains， a seed setting rate of 81.7%， and a 1 000-grain weight of 20.6 g. Its grain characteristics were as follows： husked rice yield 79.8%， milled rice yield 72.5%， milled head rice yield 61.0%， grain length 6.9 mm， length-width ratio 3.9， chalky rice rate 5%， chalkiness degree 1.2%， amylose content 17.6%， gel consistency 60 mm， and alkali spreading value 6.0. The combination had fragrance， and the rice quality reached level 2 according to the ministry standards. The naturally induced identification of resistance to rice blast showed neck blast of grade 9， and high susceptibility to rice blast. The yield was 8 204.7 kg/hm which was 6.84% higher than that of the control.

② Guangheyou 33 had a full growth period of 121 d and matured 1 d earlier than the control Wuyou 308. The combination had moderate plant type， luxuriant growth， strong tillering ability， more effective panicles， colorless palea tips， large panicles and many grains， thick and strong stems， moderate 1 000-grain weight， and color change at the maturation stage. It showed a plant height of 105.2 cm， effective panicles of 3.03 million panicles/hm a total number of grains per panicle of 153.5 grains， a number of filled grains of 119. a seed setting rate of 77.6%， and a 1 000-grain weight of 24.5 g. Its grain characteristics were as follows： husked rice yield 82.0%， milled rice yield 74.8%， milled head rice yield 56.0%， grain length 7.2 mm， length-width ratio 3.5， chalky rice rate 28%， chalkiness degree 3.4%， amylose content 15.6%， gel consistency 59.3 mm， and alkali spreading value 5.7. The rice quality reached level 3 according to the ministry standards. The naturally induced identification of resistance to rice blast showed neck blast of grade 5， and medium susceptibility to rice blast. The yield was 8 155.5 kg/hm which was 6.19% higher than that of the control.

③ Yuliangyoufuxiangzhan had a full growth period of 121 d and matured 1 d earlier than the control Tianyouhuazhan. The combination had a moderate plant type， strong tillering power， effective spike more， colorless palea tips， big panicles with more grains， strong stems， good fruiting rate， moderate 1 000-grain weight， and good color at maturity. It showed a plant height of 113.7 cm， effective panicles of 3.12 million panicles/hm a total number of grains per panicle of 171.5 grains， a number of filled grains of 131.4， a seed setting rate of 76.6%， and a 1 000-grain weight of 21.3 g. Its grain characteristics were as follows： husked rice yield 80.9%， milled rice yield 72.3%， milled head rice yield 67.6%， grain length 7.0 mm， length-width ratio 4.0， chalky rice rate 3%， chalkiness degree 0.5%， amylose content 16.3%， gel consistency 62 mm， and alkali spreading value 6.3. The combination had fragrance， and the rice quality reached level 1 according to the ministry standards. The naturally induced identification of resistance to rice blast showed neck blast of grade 9， and high susceptibility to rice blast. The yield was 8 296.5 kg/hm which was 2.53% higher than that of the control.

④ Xintaiyousizhan had a full growth period of 123 d， and matured 4 d earlier than the control Tianyouhuazhan. The combination had a tight plant type， strong green leaf color， straight flag leaves， luxuriant growth， strong tillering ability， many effective panicles， colorless papilla tips， many panicles， high seed setting rate， and good color change at the maturation stage. It showed a plant height of 107.5 cm， effective panicles of 3.09 million panicles/hm a panicle bearing tiller rate of 76.5%， a total number of grains per panicle of 149.0 grains， a number of filled grains per panicle of 114.0 grains， a seed setting rate of 76.5%， and a 1 000-grain weight of 23.5 g. Its grain characteristics were as follows： husked rice yield 81.9%， milled rice yield 71.4%， milled head rice yield 60.8%， grain length 7.1 mm， length-width ratio 3.9， chalky rice rate 10%， chalkiness degree 1.7%， amylose content 15.2%， gel consistency 65 mm， and alkali spreading value 7.0. The rice quality reached level 2 according to the ministry standards. The naturally induced identification of resistance to rice blast showed neck blast of grade 9， and high susceptibility to rice blast. The yield was 8 250 kg/hm which was 1.96% higher than that of the control.

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