| In order to determine the growth,photosynthetic characteristics,nutrient accumulation and yield characteristics of two different types of rapeseed,Brassica juncea and Brassica napus,in cold and arid areas of North China,The experiment was set up in Zhangbei Experimental Station of Hebei Agricultural University from 2017 to 2018.The local Brassica juncea rapeseed variety Dahuang and the newly introducted Brassica napus variety Huayouza 62 were used as the basic materials,the adaptability test of rapeseed to three soil types and the quality comparison test of 9 rapeseed varieties were carried out;and the sowing date test was carried out with Dahuang and Huayouza 62 as materials.Using the regular and fixed sampling method,the agronomic characters including plant growth,dry matter accumulation,nutrient accumulation and yield structure characteristics were compared between two types of varieties:Brassica juncea Dahuang and Brassica napus Huayouza 62;Photosynthetic rate?Pn?,transpiration rate?Tr?,conductance to H2O?Cond?and intercellular CO2 concentration?Ci?in leaves and pods of two varieties were measured by photosynthetic apparatus Li-6400XT.Through comparison,it is concluded that Huayouza 62 has good ecological adaptation and production effect in Bashang area of North China,which provides theoretical and technical basis for adjustment of rapeseed planting structure and high quality and high efficiency production in Bashang area.The main results are as follows:1.Field tests show that Brassica napus Huayouza 62 is suitable for planting in low fertility chestnut calcareous soil field,except plant height,the other indexes are higher than meadow chestnut calcium soil field,and the yield is 149.38%higher.In the chestnut calcareous soil field with high and low fertility,9 different varieties of rapeseed were tested,the yield of Huayouza 62,Hua Shuang 5 and 8000A-409 in Brassica napus were higher,1576.5-3234.9kg·hm-2,2045.5-2351.2kg·hm-22 and 1667.6-3701.9kg·hm-2,respectively.They are 22.79%-76.34%,31.43%-63.19%and 22.86%-40.51%higher than that of Brassica juncea Dahuang?ck?,respectively.Sowing date test shows that with the delay of sowing date,in high fertility chestnut calcareous soil field,the yield of Dahuang decreased,it is suitable for early sowing,the yield of Huayouza 62 was the lowest in the second sowing date?May 9?,the highest in the third sowing date?May 19?,and it is suitable for late sowing.In the low fertility chestnut calcareous soil field,the early sowing of rapeseed?24 April?showed a low rate of emergence,Dahuang should sow on 14 May,Huayouza 62should sow on 4 May.2.The number of green leaves of two rapeseed varieties Huayuza 62 and Dahuang increased slowly in the early period,and increased rapidly from early flowering period to full flowering period,reached the peak point,and then down,the harvest period was close to zero.Leaf area and leaf area index?LAI?also showed a change trend of"single peak",and reached its peak point at full flowering period,after that,the leaves quickly littered,and Huayouza 62 had the ability to retain more leaf area than that of Dahuang at this period.The leaf area per plant of Brassica napus Huayouza 62 was 23.20%-37.36%higher than that of Brassica juncea Dahuang,while the number of leaves per plant of Huayouza62 was 15.13%-22.66%lower than that of Dahuang.The growth period of Huayouza 62 is about 10d longer than that of Dahuang,and the growth period needed to accumulate temperature of?0?was about 2015?·d,which was about 10.1%more than that of Dahuang 1830?·d.3.The diurnal variation of net photosynthetic rate?Pn?of rapeseed leaves and pods of Huayouza 62 and Dahuang showed a characteristic of near"double peak"curve,and the phenomenon of"photosynthetic midday break"existed;the peak value of Pn in the morning was higher than that in the afternoon.The net photosynthetic rate of Dahuang leaves was 9.74%higher than that of Huayouza 62,the daily average Pn was 20.08%higher,the average Pn of Dahuang leaves in the morning was 62.52%higher than that in the afternoon,and the average Pn of Huayouza 62 leaves in the morning was 66.32%higher than that in the afternoon.The peak value of Pn in Dahuang pods and Huoyouza 62are high and low,the daily average Pn was 26.56%higher than that in Huayouza 62,the average Pn of Dahuang pods in the morning was 94.97%higher than that in the afternoon,and the average Pn of Huayouza 62 in the morning was 259.67%higher than that in the afternoon.The mean value of all day Tr and Cond was 27.08%?9.4%and 38.46%?10.26%,respectively,while the mean value of all day Ci was 5.11%and 1.9%lower than that of Huayouza 62,respectively.In the view of net photosynthetic rate,there was no advantage of Huayouza 62,but the leaf area of Huyouza 62 was 23.22%higher,the area of the angular peel was 44.79%higher and the photosynthetic potential was 35.93%higher than that of Dahuang,and the transpiration rate was 8.59%-21.31%lower than that of Dahuang.4.The aboveground dry matter accumulation of the two varieties of Huayouza 62 and Dahuang showed the characteristic of the change of the"double-peak"curve,and it was a logistic growth before the full flowering period,fall?8,10 July?after the full flowering period?July 8,10?and then increased rapidly;the harvest period?17,18 August?fell again.After full flowering period,the dry matter of rape decreased due to the rapid withering of plant leaves during the period,and the decline of harvest period was due to a small number of stems and angular peels were aged and fall off and the angle explosion of the pods.The dry matter accumulation of Dahuang in 2017,due to suffer hail and bird damage at flowering period,only appeared peak value in pod stage,which was 15.82%lower than that of Huayouza 62 at the same period,and 30.06%lower than that of Huayouza 62 at harvest period;In 2018,the accumulation of dry matter was at the first peak point,Dahuang was 5.71%higher than that of Huayouza 62,and Huayouza 62 was 28.40%higher than that of Dahuang at the second peak point,Huayouza 62 was 11.05%-24.28%higner than that of Dahuang at the harvest period.The results of Logistic curve analysis showed that the average rate and maximum growth rate of dry matter accumulation of Huayouza 62 were 34.85%,35.33%higher than that of Dahuang,respectively,and the number of days of rapidly increase was 21 days longer than that of Dahuang;The accumulative potentiality of dry matter?K value?of Huayouza 62 was 46.86%higher than that of Dahuang.The dry matter accumulation of the main roots of two varieties of rapeseed also showed a"double peak"curve,and the peak value of dry matter accumulation of the main roots of Huayouza 62 was 2.71%-38.72%higher than that of Dahuang,and the fastest accumulation rate was 27.79%-42.86%higher than that of Dahuang.The characteristic of higher accumulation potentiality of dry matter of Huyouza62 plants laid the foundation for high yield of seeds.5.The contents of N,P and K in rape plants of Huayouza 62 and Dahuang decreased rapidly from the seedling period to the early period of grain filling on July 20,the contents of N and P increased steadily or slightly ascending from the early period of grain filling to the ripe period,and the content of K continued to decrease with the aging and shedding of leaves and stems.P and K contents of Huayuza 62 seeds were higher than that of Dahuang,and N content was lower than that of Dahuang at the harvest period.The accumulative dynamics of N,P and K in rapeseed plants increased continuously before the full flowering period on July 8?10?,and then decreased rapidly;Until the early period of grain filling on July 20,the accumulation of N,P increased significantly again,but the accumulation of K in Dahuang variety with shorter growth period did not increase obviously.The accumulation of N,P and K in Huayuza 62 plants were 23.68%-29.74%,9.68%-54.55%,67.5%-134.29%higher than that of Dahuang at the harvest period,respectively.Nutrient accumulation in seeds of Huayouza 62 was higher than that of Dahuang,and the biological efficiency of N,P and K were 18.73%higher,0.38%lower,8.49%lower than that of Dahuang,respectively,and 0.7%lower,11.95%higher,47.63%lower than that of Dahuang in 2018,respectively.Huayouza 62 has higher nutrient accumulation than Dahuang,and it is easier to obtain high yield and good quality.6.There was no obviouly difference in the number of effective branches per plant between Huayouza 62 and Dahuang.In terms of yield components,Huayouza 62 has a obviously advantage over Dahuang in the number of seeds per pod,which is58.82%-78.57%higher than that of Dahuang,and the number of pods per plant is at a disadvantage,which is 31.06%-47.76%lower than that of Dahuang.The high yield of Huayouza 62 benefited from the number of pods per plant.In summary,the Brassica napus"double-low"Huayouza 62 has better ecological adaptability to the ground-gas environment in the cold environment of Bashang,North China,increasing the yield by 22.8%-54.0%compared with the local traditional Brassica juncea Dahuang,and has the advantages of replacing the traditional Brassica juncea varieties in the region and building a large scale base of oilseed and landscape of rapeflower. |
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