Breeding of the New Hybrid Rape Variety Zhuoyou 1032 in Brassica napus L.

Hailin WANG Fangming JIN Yao ZHAO Hua WANG

Abstract Zhuoyou 1032 is a new double low hybrid rape variety in Brassica napus L. bred by Guizhou Zhuohao Agricultural Technology Co.， Ltd. in 2011 with the double low two type 240AB in B. napus L. as the female parent and the double low restorer 132 4R as the male parent.   In the adaptability evaluation test at 18 sites in two years， the average yield was 172.31 kg/666.7 m2， which was 4.78% higher than that of Youyan 50 （CK）; the whole growth period was about 202 d， which was earlier than Youyan 50 （CK） by 2-3 d; the plant height was 197.6 cm; the branching height was 52.1 cm; the number of effective branches was 5.55; the number of effective pods per plant was 179.7 （pods/plant）; the number of seeds per pod was 17.7; the 1 000 seed weight was 3.99 g; and the average yield per plant was 11.7 g. It has the characteristics of early maturity， fast growth， good tidiness， compact plant type， moderate plant height， strong lodging resistance， strong resistance to sclerotinia rot， medium to long pods and large 1 000 seed weight.

Key words Brassica napus L.; Zhuoyou 1032; Yield; Oil production

The discovery and utilization of the double recessive nuclear genic male sterile two line materials of Brassica napus L. have made great contributions to the research， production and industrial development of rape in China. The two original S45A and 117A sterile lines were gradually transformed and evolved， and double low， yellow seed double low， yellow seed high oil and recessive epistatic nuclear genic sterile materials have been derived. In recent years， rapeseed breeders in Guizhou Province have carried out a large number of systematic work in the breeding of yellow seed （high oil content） double low recessive genic male sterile lines and the utilization of their heterosis， and achieved remarkable results. A group of high quality hybrid rape varieties represented by Youyan， Qianyou and Deyou have been sold inside and outside Guizhou Province. The cumulative area has reached tens of millions of hectares， creating significant economic and social benefits. Zhuoyou 1032 is a new high quality hybrid rapeseed combination bred by Guizhou Zhuohao Agricultural Technology Co.， Ltd. in 2011 with the double low two type 240AB in B. napus L. as the female parent and the double low restorer 132 4R as the male parent. It once participated in the rapeseed regional trials and production trials in Guizhou Province， which were suspended due to the cancellation of rapeseed variety examination in the country. In 2014-2016， Guizhou Zhuohao Agricultural Technology Co.， Ltd. tested Zhuoyou 1032 for adaptability at 10 sites in Guizhou Province for several years， and the variety was registered and approved in China in 2018.

Source and Parental Selection Process of the Combination

Source of the combination

In the spring of 2011， Zhuoyou 1032 was bred with 1040A as the female parent and 132 4R as the male parent. In the autumn of the same year， it participated in the comparison test of new rapeseed varieties organized by Guizhou Zhuohao Agricultural Technology Co.， Ltd. in 2014-2016， the company organized the adaptability evaluation test in such 10 points as Guiyang， Zunyi， Anshun， Xingyi， Southern Guizhou， Southeastern Guizhou， western Guizhou， Zhenfeng， Meitan and Sinan.

Parental selection process

Breeding of the female parent 1040AB

In 2004， the yellow seed B. napus L. line 737 as the male parent was sexually crossed with the yellow seed hybrid rapeseed Youyan 10 as the female parent. The F 1 generation was sexually crossed with Deyou 22 1， and the offspring were shuttled between Guiyang and Weining for sib mating and directional selection. From 2009， the sterile and fertile plants in the lines with the fertility ratio （sterile plant to fertile plant ratio） at 1∶1 were sib mated， and the selection pressure was improved by increasing the quality indicators （erucic acid， glucosinolate， oil content） from generation to generation. In the summer of 2010， the yellow seed double low （low erucic acid and low glucosinolate） recessive genic male sterile two type line 1040AB was obtained （as shown in Fig. 1）.

Breeding of the male parent 132 4R

In 2005， D5R×9801 and 892 4×9901 were sexually crossed. In 2006， D5R×9801 as the female parent was sexually crossed with the combination 892 4×9901. The offspring were subjected to large group isolation and open pollination for two generations; and excellent single plants were planted into rows for directional selection. The excellent lines were self crossed by bagging， followed by quality analysis. In the spring of 2010， the stable restorer line 132 4R was obtained （ as shown in Fig. 1）.

Characteristics

Growth period and yield performance

Variety comparison test

In the rapeseed variety comparison test in 2011-2012， the yield per unit was 186.7 kg/666.7 m2， which was 9.52% higher than that of Zhuoyou 11 （CK）， ranking the third in the tested combinations.

Adaptability test in Guizhou Province

In the multi site adaptability test of this variety in 2014-2015， the average yield was 172.31 kg/666.7 m2， which was 4.78% higher than that of Youyan 50 （CK）. Among the eight test sites， six showed a yield increase， two sites showed a yield decrease， and the sites with an increased yield accounted for 75%. The average yield in 2015-2016 was 164.88 kg/666.7 m2， which was 9.77% higher than that of Youyan 50 （CK）. Among the 10 sites， eight sites showed an increased yield， accounting for 80%. The average yield in the two years was 168.60 kg/666.7 m2， which was 7.28% higher than that of Yanyan 50 （CK）. Among the 18 production sites， 14 sites showed an increased yield， and the sites with an increased yield accounted for 77.78%. The average oil content was 67.90 kg/666.7 m2. The average growth period was 201.9 d， which was earlier than the CK by 2.3 d.

Production test

In the rapeseed production test carried out in Zunyi， Sinan， western Guizhou， Anshun， Southeastern Guizhou and Zhenfeng in 2016， Zhuoyou 1032 showed an increased yield at five sites among the six test sites， and the average yield was 178.55 kg/666.7 m2， which was higher than that of Youyan 50 （CK） by 6.35%; and the average oil content was 73.07 kg/666.7 m2， which was 4.94% higher than that of Youyan 50 （CK）.

Main biological traits

The male parent （132 4R）

The male parent belongs to B. napus L. The cotyledon is kidney shaped， and there are 2-3 pairs of shallow leaves. The leaf is normal green， with wax powder; and the leaf margin is serrated. The plants are semi erect at seedling stage， and have the characteristics of compact plant type， moderate plant height， medium growth potential， good uniformity， strong lodging resistance and long pods. The whole growth period was  205 d ; the plant height was 187.6 cm; the branching position was 75 cm; the number of branches was 6-7; the number of effective pods per plant was 238.5; the number of seeds per pod was 21.8 seeds/pod; and the 1 000 seed weight was 3.79 g.

The female parent （1040A）

The female parent belongs to  B. napus  L. The cotyledon is kidney shaped， and there are few shallow leaves. The leaf is normal green， with wax powder; and the leaf margin is obviously serrated. The plants are semi erect at seedling stage， and have the characteristics of moderate plant height， strong lodging resistance， good tolerance to sclerotinia rot， short to medium pods， good growth potential and good uniformity. Under the ecological and cultivation conditions in Guizhou Province， the whole growth period was about 210 d; the plant height was  172.5 cm ; the branching position was 62 cm; the number of branches was 6-8; the length of the main inflorescence was  58 cm;  the number of effective pods per plant was 204.7; the number of seeds per pod was 14.7 seeds/pod; and 1 000 seed weight was 3.85 g.

The hybrid （Zhuoyou 1032）

The hybrid belongs to B. napus L. The cotyledon is kidney shaped; and the top leaf is broadly elliptical， and there is 1-3 pairs of shallowly lobed leaves. The leaf is normal green， with wax powder; and the leaf margin is obviously serrated. The plants are semi erect at seedling stage， and have the characteristics of compact plant type， moderate plant height， strong lodging resistance， good tolerance to sclerotinia rot， medium to long pods， large seeds， strong growth potential and high uniformity. The plant height was 197.6 cm; the branching height was 52.1 cm; the number of effective branches was 5.55; the number of effective pods per plant was 179.7 （pods/plant）; the number of seeds per pod was 17.7; the 1 000 seed weight was  3.99 g ; and the average yield per plant was 11.7 g.

Agricultural Biotechnology2019

Quality and Resistance

Guizhou Rapeseed Institute conducted quality analysis on the commercial seeds collected from such five sits as Guiyang， Anshun， Xingyi， Meitan and Zunyi with a near infrared meter. The erucic acid content was 1.93%; the glucosinolate content was 31.69 μmol/g; the oil content was  40.85% ; and the grain protein content was  23.87% . Guizhou Rapeseed Institute determined the rape to have the incidence of sclerotinia rot of 15.53% with the disease index of 10.77， and the resistance to sclerotinia rot was moderate.

Reproduction Techniques of the Parents and Hybrid

The male parent

The seeds provided by the breeder are planted into rows， and typical plants are selected for the reproduction of the breeder’s seeds by selfing. Single plants are selected for quality analysis， and the qualified single plants are isolated with mosquito nets for the reproduction of stock seeds. The stock seeds are used for the production of production seeds in the isolation zone with the isolation distance greater than 500 m.

The female parent

In the line planted with the seeds provided by the breeder， the fertile plants are bagged， and the sterile plants are pollinated， to reproduce the breeder’s seeds. In the isolation zone， stock seeds are produced by net isolation plus artificially assisted pollination in the isolation zone， during which the sterile plants are marked with red paint. The stock seeds are propagated in the isolation zone with an isolation distance over 1 000 m， to obtain the production seeds.

The hybrid

The hybrid seeds are produced in the isolation zone with fertility above average and convenient drainage having the isolation distance over 1 000 m. The male parent is sown on about September 8， and the female parent is sown on September 12 16 （the sowing time interval of the male and female parents is 4-8 d）. The area ratio of the production field to the seedbed is 20∶1 for the male parent and （6-7）∶1 for the female parent. The best transplanting age is 25-30 d， and the male parent to female parent ratio （row ratio） is 1∶3 5. In terms of fertilization， 45% （15∶15∶15） compound fertilizer 40-50 kg/666.7 m2 + boron fertilizer 0.5-1.0 kg/666.7 m2 is adopted as the base fertilizer; and 15-20 kg of  urea  is topdressed as the Huoke fertilizer， Kaipan fertilizer and La fertilizer， 3 times in total according to the ratio of 3∶4∶3， among which the La fertilizer is added with 3-5 kg of potassium fertilizer and applied before winter， combined with intertillage. At seedling stage and wintering stage， abnormally shaped plants are removed twice; and about 50% of the fertile plants in the female parent lines are removed in time before the flowering of the female parent， and the male parent is cut after the flowering. After maturity， the female plants are harvested， and threshed， dried and bagged within 5-7 d.

Main Cultivation Techniques

Seeding and seedling management

For seedling raising and transplanting， sowing is carried out in early or mid September; the ratio of the production field to the seedbed is 1∶（7-9）. The seeding rate is 400-500 g/666.7 m2; after emergence， the seedlings are thinned at the dense part， and the management of fertilizer and water is strengthened to cultivate strong seedlings. As to direct seeding， seeding is carried out in late September and early October by hole sowing or drill seeding at the seeding rate≤400 g/666.7 m2.

Transplanting and field management

Timely transplanting

According to the weather and the age of the seedlings， the transplanting is carried out at the right time， and the best leaf age for transplanting is 5-7 leaves.

Rational close planting

The suitable density for transplanting is 7 000-10 000 plants/666.7 m2， and the density of reserved seedlings in direct seeding is 14 000-18 000 plants/666.7 m2.

Scientific fertilization

45% （15∶15∶15） compound fertilizer  40-50  kg/666.7 m2 + boron fertilizer 0.5-1.0 kg/666.7 m2 is adopted as the base fertilizer. Then， 15-20 kg of urea is topdressed as the Huoke fertilizer， Kaipan fertilizer and La fertilizer， 3 times in total according to the ratio of 3∶4∶3， among which the La fertilizer is added with 3-5 kg of potassium fertilizer and applied before winter， combined with intertillage.

Control of diseases and pests

At the seedling stage， Virtako and chlorpyrifos are sprayed to control cabbage caterpillars and  aphids.  After spring or at the flowering stage， carbendazim and methyl thiophanate are sprayed to prevent sclerotinia rot and downy mildew.

Timely harvesting

When 80% of the pods on the main inflorescence （70% of the pods on the whole plant） turn yellow and the seeds are mature in dark brown （or yellow and brown）， the plants are cut. During harvesting， the harvested branches are placed on the stems to avoid direct contact with the field， and within 5-6 d， and threshing and drying are performed in time when the weather is fine. If using mechanical harvesting， when 90% of the pods on the whole plant turn yellow， harvesting and threshing are performed at one time， and the seeds are dried， packed and put into the warehouse in time.

References

[1] TANG XH， CHEN ZN， WANG H， et al. Breeding of Huayou 203， a new hybrid Brcssica napus variety[J]. Guizhou Agricultural Sciences， 2011， 39（12）： 33-34， 37. （in Chinese）

[2] HOU GZ， WANG H， ZHANG RM， et al. Breeding and genetic analysis of the new nuclear male sterile material 117AB in Brassica napus L.[J]. Chinese Journal of Oil Crop Sciences， 1992（2）： 10-13. （in Chinese）

[3] LIN WH， WANG H， WANG HL. Breeding and application of dual purpose line 1357 AB with the recessive GMS in Brassica napus L.[J]. Seed， 2010， 29（8）： 122-123， 127. （in Chinese）

[4] WANG SB， LI Y， CHEN GP， et al. Breeding and Utilization of the New rape variety Hanyou 7 in Brassica napus L.[J]. Anhui Agricultural Science Bulletin， 2018， 24（23）： 41， 101. （in Chinese）

[5] CHEN J， RAO Y. Breeding of double low high yield resistant hybrid rape variety Qianyou 12 with disease I： Breeding of the female parent SAB 3 and its basic characteristics[J]. Seed， 2004（12）： 71-73. （in Chinese）

[6] WANG J， ZHANG TP. Genetic study of genic male sterile line （ZWAB） in Brassica napus L.[J]. Seed， 2003（5）： 8-11. （in Chinese）

[7] CHEN DL， ZHANG RM， ZENG ZL， et al. Breeding of cytoplasmic male sterile line 9171A in Brassica napus L.[J]. Guizhou Agricultural Sciences， 2018， 46（12）： 10-12. （in Chinese）

[8] ZHANG SL， LIU QR， DAO RZ， et al. Breeding and application of variety Yuhongyou 3 in Brassica napus L.[J]. China Seed Industry， 2018（1）： 68-70. （in Chinese）