Acta Agriculturae Zhejiangensis

Molecular detection and breeding application of some disease and insect resistance genes of japonica rice varieties/lines recently developed in Zhejiang Province

HUANG Xuan, JIN Lincan, YE Chaohui, JIANG Jiefeng, SHI Xianbo

2021, 33(7): 1159-1169. DOI: 10.3969/j.issn.1004-1524.2021.07.01

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In order to clarify the distribution of some disease and insect resistance genes of japonica rice varieties/lines recently developed in Zhejiang Province, in this study, the distribution of blast resistance gene Pita, Pib, Pigm,Pi9, Pi1, Pikh/Pi54, Pi2, Pi5, Pit, Pb1, Pikm and BPH resistance gene Bph14, Bph15, bacterial blight resistance gene Xa21, Xa23 in 61 japonica rice varieties/lines were analyzed.The results showed that the highest detection frequency of rice blast resistance gene was Pib, the distribution frequency was 91.80%, the distribution frequency of Pikm, Pi2 and Pita were 68.85%, 67.21%, 63.93%, respectively; the distribution frequency of Pit, Pi5, Pi9, Pikh/Pi54 were 34.43%, 32.79%, 26.23% and 24.59%, respectively. The distribution frequency of Pb1 and Pigm were 6.56%, 1.64%,respectively. The Pi1 was not distributed in 61 tested varieties/lines. The distribution frequency of Bph14 and Bph15 were 6.56% and 11.48%, respectively. The bacterial blight resistance gene Xa21 and Xa23were not distributed in 61 tested varieties/lines. In this study, Xa23, Bph14 and Bph15 were introduced into japonica rice by marker assisted selection, and the results showed that the above genes had good resistance. In this study, the distribution of resistance genes of 61 japonica rice varieties/lines in Zhejiang Province were preliminarily established, the results of this study will provide a scientific basis for transferring the target resistance genes into the varieties to be improved and breeding new varieties with broad-spectrum and multi resistance.

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Obtaining and genetic analysis of hybrid progeny between Brassica napus cv. Xiangyou 15 and Brassica campestris ssp. pekinensis

CHEN Jipeng, LIU Xiaolin, LI Shengqiang, LIU Xianjun, HU Yueqing, CHEN Tao

2021, 33(7): 1170-1176. DOI: 10.3949/j.issn.1004-1524.2021.07.02

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In the present study, Brassica napus cv. Xiangyou 15 and B. campestris ssp. pekinensis were used as parents to obtain the interspecific hybrid, and the second generation was gained by self-crossing to obtain rapeseed germplasm with valuable traits. And the meiosis of pollen mother cells (PMCs) were observed via microscope. The results showed that it was easier to obtain hybrid progenies when B. napus was used as female parent, but it was more difficult when B. campestris was used as female parent. The plant type and leaf morphology of progenies from reciprocal crosses were similar to those of B. napus. At the diakinesis, the majority of the chromosomes formed bivalents or univalents, and a few of chromosomes formed multivalents. At metaphase and anaphase, laggard chromosomes and anaphase bridges were observed in PMCs. The stamen did not develop very well and a lot of pollens were not fertile, and the seed setting rate was relatively low in the first generation. The pollen fertility and seed setting rate of the second generation were significantly (P<0.01) higher than those of the first generation. It is expected that the hybrid fertility will be restored well via selfing crossing, which can be used as genetic resources for further genetic improvement of B. napus.

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Correlation and regression analysis on body mass and body size index of Xinjiang brown cattle

LI Tao, ZHANG Mei, LIU Jianming, CHU Hongzhong, CHEN Chunhua, YANG Guangwei, TUAN Yong, QIU Meiyu

2021, 33(7): 1177-1183. DOI: 10.3969/j.issn.1004-1524.2021.07.03

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The experiment was conducted to explore correlation between body mass and body size and constructed regression equation for different growth stages in Xinjiang brown cattle, so as to provide an effective and direct method for Xinjiang brown cattle breeding. Four individual size indexes and body weight in 4 growth stages(6 months, 12 months, 18 months and 24 months) of Xinjiang brown cattle were measured and the correlation analysis and stepwise linearity regression analysis were performed in Yili area. There was a significant correlation between body weight and body size for different growth stages of Xinjiang brown cattle (P<0.01), the correlation between body size indexes and body weight was higher than others growth stage at 12 months old, and other body size indexes also showed a significant correlation(P <0.01).By the regression models estimating body mass for different growth stages of Xinjiang brown cattle, the optimal regression equations and the coefficients were 0.60, 0.63, 0.55 and 0.44, which indicated that there was a significant linear relationship between body weight and body size index in each stage. The correlation and regression analysis had constructed 4 linear regression equations for different growth stages of body mass and body weight, which was of great significance to Xinjiang brown cattle breeding in practice.

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Effect of Pulsatilla saponin B4 on treatment efficiency and serum inflammatory and immune factors of dairy cows with clinical mastitis

SHEN Liuhong, QIAN Bolin, YOU Liuchao, ZHANG Yue, SHEN Yu, LYU Shangkui, XIAO Jinbang, YU Shumin, SU Zhetong, DONG Ke, YANG Shilin, FENG Yulin, CAO Suizhong

2021, 33(7): 1184-1191. DOI: 10.3969/j.issn.1004-1524.2021.07.04

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To investigate the effects of Pulsatilla saponin B4 on therapeutic effect, serum inflammatory and immune factors in dairy cows with clinical mastitis, 12 healthy dairy cows were selected as the control group, and 36 clinical mastitis cows were selected as the test group and were randomly divided into low, middle and high dose group. Cows in test group were administered with Pulsatilla saponin B4 injection (with doses of 0.025, 0.05, 0.1 mL·kg^-1, respectively) through cervical intramuscular injection once a day for 6 days, whereas no medicine was administered in the control group. The effective and cure rates of cows in the test group were recorded, venous blood samples were collected (any day in the control group and the 1^st, 3^rd, 5^th, 7^th day in the test group) to measure serum inflammatory and immune factors, as well as milk in the infected quarters on the 1^st, 7^th, 12^th day in the test group to conduct somatic cells count (SCC) and pathogenic microorganism isolation and identification during this experiment. Cows were observed till the 12^th day and the therapeutic efficiency was recorded. It was shown that the clinical cure rate and effective rates of low, middle and high dose group were 75.00%, 75.00%, 91.67% and 100%, 100%, 100%, respectively, and the average cure time was 6.33, 6.11, 6.91 d, respectively. The Pulsatilla saponin B4 could significantly (P<0.05) attenuate SCC. Before treatment, 34 out of 36 milk samples were positive with pathogenic microorganism, indicating a detection rate of 94.44%, which mainly consisted of mycoplasma, cocci and Escherichia coli. After treatment, the total negative rate was 52.94%, among which, the negative rate of Bacilli, Staphylococcus chromogenes, Staphylococcus haemolyticus and Escherichia coli were 100%, while the negative rates of mycoplasma, Staphylococcus aureus, Staphylococcus epidermidis and coccus were 69.23%, 60.00%, 50.00% and 33.33%, respectively. Besides, Pulsatilla saponin B4 could significantly (P<0.05) promote the recovery of inflammatory factors CRP, SAA, HP, IL-1α, IL-1β, IL-2, IL-6, IL-8, TNF-α and immune factors IgA, IgD, IgE, IgG, IgM to normal levels.

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Analysis of mRNA transport of BcSVP of Chinese flowering cabbage in heterograft

TAO Peng, ZHAO Yanting, YUE Zhichen, LEI Juanli, LI Biyuan

2021, 33(7): 1192-1198. DOI: 10.3969/j.issn.1004-1524.2021.07.05

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For confirming mRNA long-transport of BcSVP gene, shoot apex of head cabbage was grafted on inflorescence stem of Chinese flowering cabbage to construct head cabbage-Chinese flowering cabbage heterograft. Based on transcriptome sequencing read library of Chinese flowering cabbage and head cabbage, coding sequences and 3’UTR sequences of BcSVP and BoSVP gene were obtained by read joining. According to interspecific differential sequences of BcSVP in 3’UTR (CF and CR), The two and one transported BcSVP reads of Chinese flowering cabbage were identified from transcriptome sequencing read libraries T01 and T02 of shoot apexes of head cabbage scions of head cabbage-Chinese flowering cabbage heterograft, respectively. The endogenous transcriptional expression of BoSVP was analyzed based on interspecific differential sequences of BoSVP(GF and GR), indicating the transcriptional expression of BoSVP did not show obvious difference between homograft and heterograft. The study indicated mRNA long-transport of BcSVP in heterograft. It lays the foundation for further study of molecule mechanism and biological function of BcSVP mRNA transport in head cabbage-Chinese flowering cabbage heterograft.

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Effects of combined application of organic fertilizer and chemical fertilizer on nutritional quality and volatile compounds of cauliflower

LI Ju, XIE Bojie, WEI Shouhui, ZHANG Guobin, WU Yue, TANG Zhongqi, XIAO Xuemei, YU Jihua

2021, 33(7): 1199-1211. DOI: 10.3969/j.issn.1004-1524.2021.07.06

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In the present study, the cauliflower cultivar Lihe Qinggeng 100 days was used as the experiment material, and six fertilization treatments were set as follows: CK1, no fertilization; CK2, conventional fertilization; T1, balanced fertilization; T2, balanced fertilization+3 000 kg·hm^-2 bio-organic fertilizer; T3, balanced fertilization+6 000 kg·hm^-2 bio-organic fertilizer; T4, balanced fertilization+12 000 kg·hm^-2 bio-organic fertilizer. The effects of different treatments on nutritional quality and volatile compounds quantity and content of cauliflower were studied. The results showed that compared with CK2, application of bio-organic fertilizer combined with chemical fertilizer could increase nutrients contents and volatile compounds in cauliflower. Compared with CK2, vitamin C content under T3 treatment was significantly (P<0.05) increased by 17.6%. Ca content under T2 and T3 treatments was significantly (P<0.05) increased by 14.3% and 36.8%, respectively. Compared with CK2, T2, T3 and T4 treatments increased the number of volatile compound types in cauliflower by 8, 12 and 13, respectively, and the contents of ketones under these treatments were increased by 3.4, 2.9 and 7.1 times, respectively. In addition, T2 and T3 treatments increased the types and contents of characteristic volatile compounds with green, fruity and floral flavor. The comprehensive evaluation results based on the principal component analysis of nutritional quality indexes and volatile compounds showed that the scores decreased as T3>T2>T4>CK2>T1>CK1. Therefore, balanced fertilization+6 000 kg·hm^-2 bio-organic fertilizer was the most appropriate fertilizer mode under the experiment conditions.

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Effects of three growth promoting bacteria and their mixed microbial agents on growth and quality of lettuce

HUANG Shuchao, HOU Dong, YUE Hongzhong, KONG Weiping, ZHANG Dongqin, LI Yali, HAN Dongrong, XIE Bojie

2021, 33(7): 1212-1221. DOI: 10.3969/j.issn.1004-1524.2021.07.07

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To verify the effects of strains GNB6, MGBC3, MGBD1 and their mixture on the growth and quality of lettuce, and to determine the optimal dosage of different strains and their mixture, so as to provide basis for the development of special growth promoting bacteria for lettuce, a total of 13 treatments were set up in this study, including nitrogen fixing bacteria A (2 mL per plant, 4 mL per plant, 6 mL per plant), phosphate solubilizing bacteria B (2 mL per plant, 4mL per plant, 6 mL per plant), IAA secreting bacteria C (2 mL per plant, 4 mL per plant, 6 mL per plant), mixed microbial agent D (2 mL per plant, 4 mL per plant, 6 mL per plant), and water control (CK).The results showed that: under the same fertilization conditions, adding the appropriate amount of single and mixed microbial agents could significantly promote the growth of lettuce, improve the nutritional quality of lettuce, effectively promote the accumulation of anthocyanins in lettuce leaves, and significantly reduce the content of nitrite in lettuce stems. Among them, D3 treatment was the best, with the stem diameter and single plant weight increased by 24.71% and 55.67% respectively compared with CK. The soluble protein of stem and leaf increased by 83.49% and 139.46%, soluble sugar of stem and leaf increased by 51.28% and 29.19%, V_C content of stem and leaf increased by 88.89% and 13.57%, nitrate content of stem decreased by 1.47%, anthocyanin content of leaf increased by 53.63%.According to the principal component analysis, the comprehensive scores of each treatment group from high to low were: D3>B1>C2>B2>D2>A2>D1>C3>A1>A3>B3>C1>CK. Comprehensive analysis showed that the most suitable dosage of each microbial agent was A2 (4 mL per plant), B1 (2 mL per plant), C2 (4 mL per plant), D3 (6 mL per plant), and the mixed microbial agent D3 (6 mL per plant) had the best effect on promoting the growth and improving the quality of lettuce.

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Genetic diversity analysis and construction of DNA fingerprint of yam (Dioscorea oppositeac Thunb.) germplasm by cpSSR marker

ZHANG Jingzhen, WANG Lianjun, LEI Jian, CHAI Shasha, YANG Xinsun, ZHANG Wenying

2021, 33(7): 1222-1233. DOI: 10.3969/j.issn.1004-1524.2021.07.08

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In order to provide molecular foundation for the innovative parental selection and the varieties improvement of Dioscorea oppositeac Thunb. germplasm, in present study, the molecular fingerprints of 64 accessions of D. oppositeac from home and abroad were mapped and the genetic diversity was analyzed using cpSSR molecular markers technology. The results showed that 10 pairs of primers were selected from 21 pairs of cpSSR primers.The genome DNA of 64 accessions of D. oppositeac germplasm were amplified by 10 pairs of cpSSR primers with stable amplification, high polymorphism selected from 21 pairs of primers. Sixty-nine bands were got totally, of which 59 were polymorphic bands, and the rate of polymorphic bands reached as high as 85.51%. The average number of observed alleles (Na) was 2, the mean effective allele (Ne) was 1.569 3 (1.231 1-1.916 0), and the average Shannon’s information index was 0.560 6(0.329 0-0.671 1), the average Nei’s genetic diversity index (He) was 0.378 1 (0.184 8-0.478 1),indicating a rich genetic diversity. Based on genetic similarity coefficient (GS), which ranged from 0.55 to 0.93, the phylogenetic relationships of 64 D. oppositeac germplasm resources were analyzed. When the threshold value of genetic similarity coefficient was 0.63, all the tested materials could be clustered into 4 classes. With the principle of identifying 64 D. oppositeac germplasm resources with a minimum number of primers, 2 pairs of primers were used to successfully construct DNA fingerprint.

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Study on genetic diversity,population structure and genetic differentiation of tea germplasm in Guizhou

AN Hongwei, SONG Qinfei, NIU Suzhen

2021, 33(7): 1234-1243. DOI: 10.3969/j.issn.1004-1524.2021.07.09

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In this study,68 EST-SSR primers were used to analyze the genetic diversity, population structure and genetic differentiation of 144 tea germplasm resources, which were divided into three groups by different altitude ranges and species: Gro1 represented the tea population of Camellia tachangensis(F.C.Zhang) and over 1 500 m altitude, Gro2 represented the tea population of Camellia sinensis(L.) O. Ktze and altitude from 1 000 to 1 300 m, and Gro3 represented a population whose altitude and species are not obvious. The tea germplasmresources were analyzed according to species, zones and altitude ranges, Gst was 0.079 7, 0.067 7, 0.047 0, Nm was 5.774 1, 6.885 2, 10.134 8, respectively, which showed that genetic variation existed among different individuals within populations, and there were strong gene communication among different populations.The greater the altitude gap was,the farther the genetic distance was.This study further explained the altitude effect on the tea germplasm distribution in Guizhou,laid the foundation for further study on the evolution and distribution law of tea germplasm resources in Guizhou.

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Diversity analysis of 30 tea (Camelia sinensis) germplasm resources in Chongqing based on agronomic traits and biochemical components

ZHAI Xiuming, LI Jie, TANG Min, HU Fangjie, ZHANG Jun, HOU Yujia, XU Ze

2021, 33(7): 1244-1255. DOI: 10.3969/j.issn.1004-1524.2021.07.10

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In order to better develop and utilize tea germplasm resources in Chongqing and understand their genetic diversity, 30 agronomic traits and five main biochemical component indices of 30 preserved resources were identified and evaluated in this study. The results showed that there were varying degrees of variation in agronomic traits and main biochemical components of Chongqing tea resources. Coefficient variation of agronomic traits were 11.01%-53.54%, the average coefficient variation was 29.13%. The diversity index was 0.32-2.04, the average diversity index was 1.16; Coefficient variation of the main biochemical components was 11.87%-28.56%, the average coefficient variation was 19.4%; The diversity index was between 1.91-2.07, and the average diversity index was 2.00. The cumulative contribution rate of the first nine principal components was up to 74.85%, which contained most of the information of 35 trait indicators, could be used to comprehensively evaluate Chongqing tea germplasm resources. Through cluster analysis, 30 Chongqing tea resources were divided into three groups, the Ⅰ and Ⅱ groups might be applied to process green tea and black tea, the Ⅲ group was the high-quality raw materials for black tea. This study screened 1 germplasm with bud color variation, 3 germplasms with thick fluff in bud and leaves, 10 germplasms with early budding, 21 germplasms with high tea polyphenol, 4 germplasms with high caffeine.

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Effects of different plant growth regulators on hardwood cuttage of persimmon rootstock Yalin 6

WU Kaiyun, GONG Bangchu, XU Yang, ZHANG Pingsheng

2021, 33(7): 1256-1263. DOI: 10.3969/j.issn.1004-1524.2021.07.11

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The cuttings of Yalin No.6 were collected from the nursery of immature rootstock, and the rooting experiment of hardwood cutting was carried out. IBA, ABT1, NAA, GGR6, IAA and other plant growth regulators were used to prepare different concentrations of solution and water was used as the control for the cutting immersion, then the cuttings were soaked and cut in sterile medium. After 45 days of shading film moisturizing environment and 15 days of open-air drip irrigation environment, the rooting effect was detected by sampling, significant difference analysis and multiple comparative analysis. The results showed that there were significant differences in rooting effect among different treatments. IAA, IBA and GGR6 had higher rooting rate and sprout growth under appropriate ratio. The rooting rates of A1, G3 and G2 were 75.6%, 56.9% and 52.8% respectively, which were significantly higher than those of other treatments. The changes of rooting rate and callus occurrence rate were not consistent. There are three types of rooting: cortex rooting, callus rooting and mixed rooting. In the experiment, the cutting rooting was mainly cortex rooting, supplemented by mixed rooting. IAA and other treatments can improve the cortex rooting, while NAA and IBA with humic acid could promote the rooting of callus. IAA and other treatments can improve the rooting rate of cortex, 250 mg · L^-1 IAA treatment had the best rooting effect, 500 mg · L^-1 GGR6 treatment was the second. Considering the cost advantage and operation convenience, it was suggested to use 500 mg · L^-1 GGR6 treatment to cultivate persimmon rootstock cuttings.

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Analysis on influencing factors and spatial distribution of leisure agriculture at provincial level based on geographic big data: a case study of Zhejiang Province, China

YE Han, WU Bowen, XU Hongwei, GAN Muye, ZHANG Jing, WANG Ke

2021, 33(7): 1264-1274. DOI: 10.3969/j.issn.1004-1524.2021.07.12

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Most of the current studies on the spatial distribution of leisure agriculture are based on the traditional survey data. With the development of online electronic maps, POI (point of interest) data and driving time data provide new big data sources, yet there are a few examples of this kind of big-data-based study on spatial distribution of leisure agriculture at the provincial level. Based on POI data from Gaode Map and driving time data from Baidu Map, with methods including Nearest Neighbor Index and Kernel Density Estimation, and implementation of Geographic Detector, tthe spatial distribution characteristics and influencing factors of leisure agriculture in Zhejiang Province were studied. It is shown that leisure agriculture has a multi-core agglomeration distribution at the provincial level, with apparent dependence of cities and scenic spots, forming core dense area including Hangzhou-Huzhou junction and Anji County, as well as several urban dependent and scenic dependent dense areas. The types of leisure vacationing, rural farm work experiencing, agritainment and back-to-nature entertainment show continuous clusters due to geographic location and terrain characteristics, while the folk custom experiencing and villages and townships sightseeing types show weak geographic links and are more evenly distributed. The number of science and education touring type POIs is quite small. The levels of economic and agricultural development, together with income and consumption capability, are important social and economic factors affecting the intensive distribution of leisure agriculture. Overall, in areas with certain natural resources, high levels of economic and agricultural development, or where residents have relatively high consumption capability and the tourist market is large, or where transportation is relatively convenient, a better environment for leisure agriculture development is likely to be provided.

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Effects of soil conditioner application on pH value of acidified soil and root characteristics of flue-cured tobacco

CHEN Gui, ZHOU Jiewen, LI Haiping, ZHANG Faming, LI Chunshun, LIU Li, ZHANG Y

2021, 33(7): 1275-1282. DOI: 10.3969/j.issn.1004-1524.2021.07.13

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To clarify the dynamic variations of soil pH value and the effect on the root characteristics of flue-cured tobacco of soil conditioner application in acidified tobacco-planting soil, a pot experiment was conducted with soils of Changning County and Tengchong City, Baoshan City, Yunnan Province. The used soil conditioners consisted of lime, woody peat-based potassium humate (potassium humate for short)+hydrothermal mineral potassium fertilizer (mineral potassium fertilizer for short), potassium humate+calcium magnesium phosphate fertilizer. Also, potassium sulfate was used as one treatment besides the blank control (CK). The results showed that the soil pH value presented a trend of decreasing first and then gradually increasing after the addition of potassium humate+mineral potassium fertilizer and potassium humate+calcium magnesium phosphate fertilizer within 60 d. Lime application increased soil pH in a short time, yet it tended to become more acid for the long run. The application of potassium humate+mineral potassium fertilizer and potassium humate+calcium magnesium phosphate fertilizer significantly (P<0.05) increased the rhizosphere organic acid content, root activity, root ATPase activity and above-ground biomass of tobacco. In the soil of Tengchong City, compared with CK, root biomass was significantly (P<0.05) increased by 46.09% and 83.70%, respectively, after applying potassium humate+mineral potassium fertilizer and potassium humate+calcium magnesium phosphate fertilizer.In general, the application of potassium humate+mineral potassium fertilizer and potassium humate+calcium magnesium phosphate fertilizer could slow down the acidification of the acidified tobacco-planting soil, which is also beneficial for the growth and development of tobacco plants.

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Isolation and identification of fungi from mildewed feed corn and study on anti-mildew and antifungal effects of lactobacillin

JIANG Yuhang, XIN Weigang, ZHANG Qili, DENG Xianyu, WANG Feng, LIN Lianbing

2021, 33(7): 1283-1291. DOI: 10.3969/j.issn.1004-1524.2021.07.14

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To clarify composition of fungi species in mildewed feed corn and explore antifungal effect of lactobacillin on mildewed fungi and the effect of delaying feed corn mildewing, in this study, mildew fungi were isolated from mildewed feeding corn by using traditional fungi culture method, and the taxonomic status of culturable fungi in mildewed feed corn was determined by sequencing of ITS amplicons. The inhibitory effect of lactobacillin on mildew fungi was evaluated using the Oxford Cup method, and crude lactobacillin with different proportions (10%, 20%, 30%) were set to explore mildew cycle and mildew degree of lactobacillin on delayed feeding corn mildew (caking, mildew spot, mildew taste, and mildew number were taken as observation indices). The results showed that diversity of fungi species in mildewed feeding corn was high, and five genera of fungus (Aspergillus, Penicillium, Mucor, Fusarium and Geotrichum) belonging to three phyla were screened. Lactobacillin had a good inhibitory effects on mildew fungi of various genera in mildewed feed corn, it had the best antifungal activity against Penicillium crustosum, the diameter of the inhibition circle could reach (16.54 ± 0.23) mm. The antifungal activity against Geotrichum candidum was the worst, only with the diameter of inhibition zone of (9.26±0.16) mm, but their diameter of inhibition zones were significantly (P <0.05) higher than that of the control group. Different proportions of lactobacillin crude extract were added to feeding corn, there was no obvious mildew phenomen within 10 days, and there was obvious difference in the degree of mildew between the treatment groups and the control group on the 30th day. In addition, with the increasing of proportion of added lactobacillin, the mildewing degree of feed corn gradually decreased, and the fungi colonies were only (9.28±0.59) × 10⁷ CFU·g^-1 in the treatment group with 30% addition proportion. In conclusion, there were rich species of fungi in moldy feed corn, and there were a variety of toxin-producing molds; Lactobacillin could effectively inhibit mildew fungi, slow down the cycle and degree of mildew in feed corn.

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Residue dynamic and risk assessment of three fungicides in broccoli

SUN Caixia, OUYANG Zhizhou, LIU Yuhong, YU Guoguang

2021, 33(7): 1292-1299. DOI: 10.3969/j.issn.1004-1524.2021.07.15

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Pesticide residue is the key impact factor that affect vegetable quality and safety. In this article, broccoli was studied and the residue dynamic trial of three triazole pesticides including difenoconazole, tebuconazole and myclobutanil was carried out. The GC-MS method was established to detect triazole pesticides residue and dietary intake riskassessment of the three pesticides was carried out. The results showed that, according to the dietary intake data, the usage of difenoconazole and myclobutanil should be controlled and post-harvest interval should be longer than 28 days, application of tebuconazole in broccoli should be assessed further.

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Discriminant analysis of origin of Panax notoginseng and its main roots and lateral roots based on trace element analysis

ZHANG Peng, ZHANG Xi, YANG Xueyan, LIU Yuanlin, LI Ru, LONG Ming, TIAN Xiaojing, ZHANG Fumei, CHEN Shien, MA Zhongren

2021, 33(7): 1300-1308. DOI: 10.3969/j.issn.1004-1524.2021.07.16

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In this study, in order to solve the problems of main and lateral root doping of Panax notoginseng, the method of simultaneous detection of 11 elements such as Se and Cd in Panax notoginseng was established by dry digestion combined with inductively coupled plasma optical emission spectrometry (ICP-OES) technology. The range was from 95.72% to 102.3%, the correlation coefficient r value was 0.971 98 to 0.999 97, the RSD value were 0.09% to 2.88%, and all were less than 3%. Under this condition, the five different origins of Panax notoginseng and their difference in element content in main and lateral roots were detected in Yunnan. The results showed that the content of As, Pb and Cd in Panax notoginseng was not more than 0.5 mg·kg^-1; none of them exceeded the standard. FA analysis showed that the main influencing factors of the sample elements were As, Fe and Pb. The 3D and 2D mathematical models established by principal component analysis (PCA) and canonical discriminant analysis (CDA) made a clear distinction between Panax notoginseng and its main roots in 5 different production areas, and there was no overlap. The clustering analysis (CA) results were consistent with the actual production areas, and the main roots of different production areas were systematically divided into two categories. PCA and CDA analysis results were consistent. The purpose of this study was to provide a fast and accurate new method for judging the origin of Panax notoginseng and identifying the main roots and lateral roots.

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Design and experiment of hand-operated self-integrated picking machine for Carya cathayensis

LI Zansong, CAO Chengmao, WU Delin, ZHANG Jianyu

2021, 33(7): 1309-1319. DOI: 10.3969/j.issn.1004-1524.2021.07.17

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In order to improve the efficiency of picking and reduce the cost of picking, a hand-operated self-integrated picking machine for Carya cathayensis was designed and developed according to the low degree of mechanization of pecan high-altitude operation in China. The design of the key parts of the machine was designed, and the mathematical modeling and analysis calculation of the eccentric mechanism was carried out. Based on the free model response analysis of the fruit tree with ANSYS, and the frequency range of picking pecan trees was preliminarily determined to be 7-20 Hz. According to the picking test of pecan, the results showed that: vibration frequency had a significant effect on the picking rate of fruit trees (P=0.05). The picking rate of fruit increased with the increase of vibration frequency. When the vibration frequency was 22 Hz, the picking rate was 95.1%. In order to improve the picking rate and minimize the damage to buds and fruit trees, it is suggested to control the harvesting frequency at 16-18 Hz, and the average picking rate of fruits at this time was about 83.9%-88.0%.The unpicked fruit was repicked manually or mechanically.

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Design and experiment of tea garden energy-saving ditching blade

QIN Kuan, LIANG Xiaolong, CAO Chengmao, FANG Liangfei, WU Zhengmin, GE Jun

2021, 33(7): 1320-1328. DOI: 10.3969/j.issn.1004-1524.2021.07.18

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Aiming at the needs of mechanized ditching in the tea garden to reduce resistance and consumption, an energy-saving ditching blade was designed to reduce the consumption of tea garden ditching. Through theoretical design and analysis, the curve equation of energy-saving ditching blade side edge and sidelong edge were determined. Through discrete element method simulation, the sliding-cutting angle at the end of the helix of the side cutting edge and the static sliding-cutting angle from the beginning to the end of the expansion curve in the plane of the side cutting edge were determined to be 62° and 56° respectively. Field experiment was performed on the designed energy-saving ditching blade. The experiment results showed that the energy consumption of the energy-saving ditching blade were 0.093, 0.107 and 0.128 kW respectively when the ditching depth was 15, 20 and 25 cm. The power consumption of energy-saving ditching blade was less than that of general ditching blade, which indicated that the designed energy-saving ditching blade in various ditching depths were able to achieve the purpose of reducing the power consumption. In addition, the stability coefficient of ditching depth of the energy-saving ditching blade at different ditching depths was greater than 90%, which was higher than the national standard. It showed that the designed energy-saving ditching blade could reduce the energy consumption of the operation and ensure the quality of ditching.

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Tomato disease recognition scheme based on multi-scale and attention mechanism

ZHANG Ning, WU Huarui, HAN Xiao, MIAO Yisheng

2021, 33(7): 1329-1338. DOI: 10.3969/j.issn.1004-1524.2021.07.19

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The timely detection and management of tomato diseases can help increase the yield and quality of tomatoes and increase the economic benefits of farmers. The internet of things and artificial intelligence can effectively detect tomato diseases without damage. This paper proposed an improved AT-InceptionV3 (Attention-InceptionV3) neural network tomato leaf disease detection model. The network used InceptionV3 as the backbone network, combined with multi-scale convolution and attention mechanism CBAM (convolutional block attention module, CBAM) module, which enhanced disease information expression and suppressed irrelevant information interference. At the same time, transfer learning was introduced to prevent over-fitting when the sample data volume was small. In order to evaluate the effectiveness of the optimization model, an experimental simulation test was conducted on the public tomato disease data set of Plant Village. The improved model had an accuracy of 98.4% in classification of five leaf images of healthy tomato leaves, bacterial spot disease, late blight, leaf mold and yellow leaf curl vircus in the test stage, and the optimization effect was significant. In order to further verify the universality of this method in different Internet of Things, experiments had compared the model’s classification effect on disease images with different resolutions. The results showed that partial loss of image resolution would not reduce the accuracy of disease classification. This model could be used for tomato greenhouse intelligence and provide an important basis for network decision-making and judgment.

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Influence of top management team heterogeneity on technological innovation of China’s agriculture-related listed enterprises

ZHANG Hengrui, HUANG Tianzhu

2021, 33(7): 1339-1346. DOI: 10.3969/j.issn.1004-1524.2021.07.20

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Technological innovation is considered to be the key to enhance the core competitiveness of agriculture-related enterprises. As the highest decision-making body of the enterprise, top management team (TMT) plays an important role in the improvement of the technological innovation level. Based on the relevant theories of technological innovation and high-level echelon theory, the relevant data of TMT characteristics and finance status of China’s agriculture-related listed enterprises in 2017-2019 were collected in the present study, along with variables set and models constructed, to study the relationship within the heterogeneity of TMT, government subsidies and technological innovation level of China’s agriculture-related listed enterprises via empirical analysis. The results showed that the improvement of the heterogeneity of tenure, occupation and educational background of TMT was conducive to technological innovation, but the improvement of age heterogeneity of TMT inhibited technological innovation. The government subsidies positively stimulated the influence of tenure and occupation heterogeneity of TMT on technological innovation. The above results could provide references for China’s agriculture-related listed enterprises to continuously improve their technological innovation level by perfection of the TMT structure.

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