| The dry matter production,photosynthetic characteristics,root system and pod formation of 10 spring soybean varieties(lines)14-119,15-119,15-122,14-146,15-59,Hajiao 5337,Jiunong 30,14-195,Heinong 61 and Xindadou 27 were studied under field conditions,which provided theoretical basis for high yield of soybean in Xinjiang.The main conclusions are as follows:1.The yield of 14-119 and 15-119 reached 5611.6-5734.2 kg·hm-2 with the maximum leaf area index ranging from 5.78 to 5.9.The dry matter accumulation in the middle node was slightly higher than that in the upper part.The distribution of dry matter accumulation in the middle and upper parts was more reasonable.The dry matter accumulation rates in the early and middle stages of growth were higher,with the maximum accumulating rates being 23.87 g·m-2·d-1 and 21.43 g·m-2·d-1,respectively.At the later stage,stem dry matter transfer,dry matter transfer rate and contribution rate to grain were 82.04-95.40 g·m-2,30-32%and 30-31%respectively,mainly due to the increase of 7-12 knots.Rapid accumulation of dry matter in early growth stage,high contribution rate of stem to grain in late growth stage and more accumulation of total dry matter in final growth stage are one of the reasons for high yield.2.The characters of root system both high-yield lines 14-119 and 15-119 was as follows:the dry weight of total root and the length of total lateral root were larger in 0-80 cm soil layer,and the proportion of fine root with diameter ranging from 0-1.0 mm was higher,reaching 69.97-72.67%.Root injury flow rate was higher in R3-R5 stage,and the ratio of root to shoot was larger in middle and late growth stage.The root dry weight density of 0-20 cm soil layer in R3-R5 stage increased by 21.12-69.95%,11.20-52.85%and 5.20-52.38%compared with that of common yield varieties(lines).The lateral root length density of 0-20 cm soil layer in R2-R5 stage increased by 12.43-86.45%,16.43-110.69%,26.16-102.56%,25.69-105.91%and the root injury flux of R3-R5 stage increased by 7.61-92.52%,18.62-53.80%,15.83-46%respectively.Root dry weight,developed lateral roots and high wound discharge promote photosynthesis above ground,and then promote dry matter accumulation,so as to achieve high yield.3.14-119 and 15-119 have larger total petiole length,suitable plant height and stem diameter,larger middle and upper petiole length and more reasonable plant structure than other varieties(lines).The content of chlorophyll(SPAD),net photosynthetic rate(Pn)and transpiration rate(Tr)in the upper and middle parts were higher.The net photosynthetic rate and transpiration rate in the middle and upper parts of the late growth stage decreased slightly,and maintained a high photosynthetic capacity and a high photosynthetic accumulation capacity throughout the growth period.4.14-119 and 15-119 had longer flowering period and higher pod number per unit area than other varieties(lines).Flowering efficiency and pod-forming efficiency of dry matter were 8.12-8.63 per·g-1 and 1.45-1.49 per·g-1,respectively.The dropping rate of flowers and pods was more than 70%.5.Within the range of 4 527.4-5 734.2 kg·hm-2,the dry matter increment at flowering stage was quadratic with the number of flowers,and the dry matter increment at pod stage was linear with the number of pods.The order was Y1=-0.0503X12+42.285X1-53 12.2,R2=0.6739*;Y2=-0.0309X52+14.309X5-604.53,R2=0.6304*;the dry matter increment at flowering stage was quadratic with the number of flowers;the stem,leaf,stem and pod stage was quadratic with the number of pods.The relationship between dry matter increment of leaf and petiole and pod number was quadratic.Too little or too much dry matter accumulation at flowering and pod stages is not conducive to the formation of flowers and pods.The above-ground dry matter increments were 4373 kg·hm-2 and 7801 kg·hm-2 at flowering and podding stages,the total number of flowers and pods were 3773.3·104·hm-2 and 1127.3·104·hm-2 respectively,and the final yield was 5734.2 kg·hm-2. |
PDF Full Text Request