To reduce yield loss in mechanized harvesting, lodging resistance inheritance was investigated on B. napus. Two hybrids were made from 2 cultivars with different lodging resistance. They were used for constructing a DH population containing 280 lines. Lodging resistance was determined by using the crops stem strength lodging-resistance measuring device and other tools in 2 years. The inheritance was analyzed by major gene plus polygene genetic model for plant quantitative traits. Skewness and kurtosis analysis was also used. Results showed that stem mechanical resistance and stem strength were controlled by 0 gene with major effects and 9 polygenes with minor effects. No genetic interaction between stem mechanical resistance and biomass per plant was found, but complementary interactions among stem strength genes were shown. The average heritability of stem mechanical resistance and stem strength were all about 50%. The average heritability of stem diameter was 69.338%. Biomass per plant in 2 years were 52.198% and 69.284% respectively. The heritability of the above traits were relatively low. More influence came from environments. Thus the selection at early stages should not be too strict for stem mechanical resistance, stem strength, stem diameter and biomass per plant. The stem strength could explain more of the lodging resistance than stem mechanical resistance. Results suggested that more attention should be paid to stem strength for breeding.
To characterize an early embryo-specific promoter, the putative promoter region of AhDGAT3 (GenBank: AY875644.1) was isolated by nested PCR-based genomic walking method. Results showed that the 2181 bp 5´ flanking sequence of AhDGAT3 was isolated. Sequence analysis in PLACE and plantCARE database identified the core regulatory elements such as TATA-box and CAAT-box， the putative cis-acting regulatory elements involved in MeJA-responsiveness, defense stress responsiveness, light-responsiveness, heat stress responsiveness and further the seed or embryo-specific elements. For the functional and characteristic analysis of AhDGAT3 promoter, the recombinant vector pBI121-PAhDGAT3 was designated and transformed into Arabidopsis. Histochemical staining revealed that the activity of pAhDGAT3 was restricted to a short temporal and spatial window from the heart stage to torpedo stage of the embryo.
Resveratrol is an important component of phytoalexins, and it affects human cardiovascular system. In this study, the resveratrol content in seeds of 140 lines in an RIL population (Zhonghua 10 × ICG 12625) was detected by high performance liquid chromatography (HPLC) in two environments. The result showed that the variation resveratrol contents in the RIL population ranged from 38.27 μg/ kg to 352.08 μg/ kg. Four Lines (QT0339, QT0369, QT0450 and QT0454) showed stable higher resveratrol contents than the high value parent in the two environments, ranging from 143.90 μg/ kg to 215.60 μg/ kg. The resveratrol contents of these lines were higher than that of the high value parent by 32.31 %, 5.80 %, 86.46% and 79.52 % in 2014 environment and 32.31 %, 5.80 %, 86.46 % and 79.52 % in 2015 environment, respectively. A total of 13 QTLs related to resveratrol content in peanut seeds were detected by WinQTLCart 2.5 software, and showed phenotypic variations of 2.2-7.4%. Notably, qRB8.1a and qRB8.1b were repeatedly detected in both environments. The results of this study provided a theoretical basis for breeding new peanut varieties with high resveratrol content.
7S globulin subunit is the main allergen of soybean, lipoxygenase is the source of the beany flavor. Therefore, the 7S globulin subunit and lipoxygenases are necessary to be removed during the soybean processing. In this study, the ?¢, ?????subunit of 7S globulin complete deletion of "1003-44" as the female parent, "SI0162" lacking Lox-1, 2, 3 lipoxygenases complete of as the male parent, a cross was made to optimize these two traits, the new germplasm resources of double deficiencies in 7S globulin subunit and lipoxygenases were created. All 21 F1 (1003-44×SI0162) seeds displayed the absence of 7S globulin subunit, and the presence of lipoxygenases, the distribution ratio of 500 F2 phenotype for the absence and presence of 7S globulin subunit from selfed 21 F1 plants was 375:125, fitting the ratio of 3:1(X2(0.05,1)=0.0964<3.84). Moreover, the ratios of 4 phenotypes were at 282 of presence of Lox-1,2,3 :96 of absence of Lox-3 :93 of absence of Lox-1,2 :27 of absence of Lox-1,2,3 in the F2 (1003-44×SI0162) population well fit t to 9:3:3:1(X2(0.05,3)=0.6275<7.81) . These data supported the hypothesis that the absence of 7S was dominant to the presence of 7S globulin subunit. In addition, the absence of Lox-1,2,3 were recessive to the presence of Lox-1,2,3. Therefore, we concluded that the absence of 7S globulin subunit was inherited as a single dominant trait, the absence of Lox-1,2,3 were inherited as 2 recessive traits. Furthermore, we obtained two double deficiency F2:7 lines of 7S globulin subunit and Lox-1,2,3 double through long term screening by ISDS-PAGE. It suggested that the lacking of 7S globulin subunit and Lox-1,2,3 did not affect the normal plant growth and seed development of soybean. This study not only provided genetic and phenotypic basis for breeding of soybean seed composition toward improvement of seed quality, but also benefited to cultivation of special high-value soybean variety for food processing.
Using cDNA of shoot apical meristem in dwarf soybean-HK808 as template，degenerated primers were designed accoding to conserved domain of α-expansin gene of plant，a new full-length gene named GmEXPA5（accession number is JN207916.1） was isolated by RT-PCR and rapid amplification of cDNA ends（RACE）. The sequence analysis showed that GmEXPA5 had a full length of 1233 bp containing the open reading frame (636 bp), which encoded 211 amino acid with two conserved domain， domain1（expansin EG45）and domain2（expansin CBD）. Without obvious signal peptide，GmEXPA5 could be from α-expansin subfamily by alignment analysis of deduced amino acid. The pEASY-Blunt E1-GmEXPA5 recombinant plasmid was constructed and the stable prokaryotic expression system was obtained. After induced by IPTG, the analysis of SDS-PAGE gel electrophoresis showed that the relative molecular weight of the induced protein was 26 KD ，which was consistent with its theoretical value. Real-time quantitative PCR analysis revealed that GmEXPA5 was expressed in all different organs but the expression levels in wild type was significantly higher than that of HK808 in shoot tips and stems. It suggested that GmEXPA5 played an unique role in the formation of dwarf phenotype.
Crop germplasm, considered as irreplaceable strategic resources, plays a significant role in the improvement of crop breeding. In this study, online information database of sesame germplasm resources was designed and established using Lamp database technology (http://www.sesame-bioinfo.org/phenotype/index.html). This database included 90 420 items of information based on morphological and biological characteristics, quality and resistance statistics from 8 115 collected sesame germplasm. It provided primary functions including to browse and query of sesame germplasm information, to ask for listed materials. Its establishment advanced the traditional methods such as paper and computer storage, sporadic storage of sesame germplasm resource information. It adopted the digital management and the sharing of sesame germplasm into practice, and provided a technique platform for sesame germplasm protection and effective application.
Exploring fertilization patterns under corn-soybean rotation is a technological solution to minimize production costs and environmental pollution in soybean production in Northeast China. The present study investigated the effects of fertilization patterns under corn-soybean rotation on root dry matter accumulation and morphological characteristics at soil depths of 0-10cm, 10-20cm and 20-30cm, in different growth stages and the relationship with yield. The fertilization patterns were (1) applying chemical fertilizers in corn and no fertilizers in soybean (T1); (2) applying chemical fertilizers in corn and cattle manure only in soybean (T2); (3) applying chemical fertilizers in corn and half rate of fertilizers in soybean (T3); (4) applying chemical fertilizers in both corn and soybean (T4); (5) applying all fertilizers used for corn and soybean in corn only and no fertilizers in soybean (T5). The results showed that the highest soybean yield of 2959 kg•ha-1after two rotations was obtained in the treatment (T2), which was 7.3% higher than treatment (T4). The increased yield was mainly due to the improvement in plant height, number of main stem nodes, number of pods per plant and number of seeds per plant. Compared to T4 treatment, yield in T1, T3 and T5 treatments was reduced by 15.4%，8.5% and 5.0% respectively. T2 treatment significantly increased root biomass density at R6 stage with 42.3% greater than the T4 treatment in 0-10 cm soil depth, which was positively related to yield with a coefficient of 0.655(p < 0.01). Compared to T4 treatment, the T2 treatment increased the root length density by 25.3%, 71.3% in 0-10cm and 10-20cm depth at the R1 stage, and 27.6% in 20-30 cm at the R6 stage, which was significantly correlated to yield with a coefficient of 0.692(p < 0.01). Although T3 treatment significantly increased root biomass density in 10-20, 20-30 cm soil depth at R1 stage, and root length density and root surface area density in 10-20 cm at R6 stage, soybean yield was negatively correlated with them. T4 treatment only significantly increased root surface area, and had no effects on root average diameter and root surface area at other stages. Therefore, the effects of fertilization system on the relationship between soybean root properties and yield was complex. The increased yield in manure application might be due to the increase in surface root biomass density and greater root length. In areas where manure resources were available, the application of 15t/ha cattle manure after corn harvest under corn-soybean rotation, could be an alternative approach in increasing soybean yield, reducing production costs and negative impact on environment from chemical fertilizers.
From available cold tolerance germplasm, identification method was built on rapeseed (Brassica napus L.). Seedlings at 3- to 4-leaf stage were tested after 24h under 4℃ cold acclimation. Survival rates (SR) and cold tolerance index (CTI) were investigated after 3 treatments (-2℃ for 1 h, -2℃ for 1 h and -4℃ for 1 h, -2℃ for 1 h and -4℃ for 1 h and then -6℃ for 1 h). A total of 226 materials from domestic and abroad were evaluated. Results showed that the SR of the 3 treatments were from 0-100%, 0-80%, and 0-70% respectively. The CTI ranged from 0 to 52. Six strong cold tolerant germplasm were found with CTI of 33 to 52. The results from different ecological zone demonstrated that winter-, semi-winter- and spring-rapeseeds had CTI of 8.10, 7.70 and 9.10 respectively. Spring-rapeseeds were more tolerant to cold than winter and semi-winter rapeseeds.
To explore the drought tolerance of rapeseed and hybrids of Brassica napus and Brassica juncea, experiments had been carried out under drought stress at budding and flowering stages for 4 years. Tested materials included 43 lines of B. napus, B. juncea and interspecific hybrids. Drought resistance index method and cluster analysis were used. Result showed that, among the 3 yield component factors, the total pod number per plant was the most sensitive to drought. It decreased the yield by the reducing the numbers of first branch and pod number. The relative total pod number, relative collateral pod number, relative branch height and drought resistance index showed significant positive correlation under drought. Thus the relative collateral pod number and relative total pod number could be used as screening indexes of drought resistance, and relative branch number and relative plant height could be used as initial indexes. 17 drought resistant materials were found. Among them, only 2 were consistent between years, and the hybrid line 12XS256-6-1 was consistent both in drought tolerance and high yield.
To optimize fertilization of rapeseed-sesame double cropping pattern in the middle and lower regions along Yangtze River, rapeseed cultivar Huayouza 9 and sesame cultivar Ganzhi 5 were used to study the effects of nitrogen application on yield, quality and nitrogen use efficiency in field. 6 nitrogen application ratios (rapeseed : sesame) were as follows: P0=0, P1=157.5:67.5, P2=180.0:45.0, P3=202.5:22.5, P4=225.0:0, P5=180.0: 45.0 (including rapeseed cake 1 500) kg/hm2. Results indicated that rapeseed and sesame yields of 5 nitrogen treatments were significantly higher than that of control (P0), but the total yield and nitrogen use efficiency among 5 nitrogen treatments had no significant difference. The highest total yield (3 053.9 kg/hm2), total income (25 335.4 yuan/hm2), agronomic efficiency (4.1 kg/kg), partial productivity efficiency (13.6 kg/kg) were obtained under P3 condition. Compared with control (P0), the total yield and income significantly increased by 42.79% and 55.08% respectively. Seed oil content of the main inflorescence in rapeseed was higher than that of branches, while opposite result was found for protein content. Furthermore, rapeseed protein content of the main stem was significantly affected by the amount of nitrogen fertilizer application. On the other hand, the contents of sesamin, sesamolin and lignan of P3 treatment were significantly lower than that of other treatments, but oil and protein content of both rapeseed and sesame maintained at relatively higher levels. Therefore, under 202.5 : 22.5 nitrogen distribution, it not only maintained a higher yield, nitrogen use efficiency and seed quality of rapeseed and sesame, but also optimized rapeseed-sesame double cropping under decreasing nitrogen condition.
In order to further explore the mechanism of continuous cropping obstacle of peanut (Arachis hypogaea L.), effects of different concentrations of cinnamic acid, phthalic acid, p - hydroxybenzoic acid, and their mixture on peanut rhizosphere soil microbes at flowering period, early podding, end of podding stages and peanut yield were studied by using the method of exogenous add. The study results showed that at each growth period, compared with the control, all treatments decreased the quantities of peanut rhizosphere soil bacteria and actinomycetes, microbial biomass carbon and nitrogen content, respiration intensity, and increased the quantity of fungi. The allelopathy increased gradually with the increase of concentration, and the allelopathy of the mixture of the three phenolic acids was the strongest. The allelopathy of on soil fungi quantity strengthened, while weakened on the other indices with the prolonged treatment. All treatments decreased peanut production significantly (P < 0.01). The higher the concentration, the greater the reduction in peanut production. The highest concentration treatment of 90 mg kg-1 dry soil initial content for cinnamic acid, phthalic acid, p - hydroxybenzoic acid, and their mixture reduced the peanut pod yield per pot by 43.2%、32.9%、40.2% and 47.3% respectively. The accumulation of these three phenolic acids correlated with the alteration of soil microbial community structure, which was one of the possible reasons for peanut continuous cropping obstacle.
The effects of calcium application and plastic film mulching cultivation on accumulation, distribution and utilization efficiency of N, P, K in peanut（Arachis hypogaca L.）were investigated in red soil of southern China under calcium deficiency. Large seed variety Xianghua 2008 and the typical red soil under calcium deficiency were used as material for the soil column experiment from June 2014 to October 2015. Different calcium fertilizer gradients and two cultivation methods (open field and plastic film cultivation) were used in this experiment, including no calcium (Ca0), medium calcium fertilizer (Ca375) and high calcium fertilizer (Ca750). The yield, N, P, K and Ca calcium content, accumulation, distribution characteristics and utilization efficiency of peanut were studied at maturity stage. The results showed that with the increased calcium application, the accumulation and distribution of nitrogen in leaves, stems, roots, gynophore and fruit shells of peanut decreased significantly, while the accumulation and distribution of nitrogen of seed kernel and total accumulation of plant increased. Nitrogen distribution rate of leaf and gynophore decreased under plastic film cultivation. The additional calcium fertilizer was beneficial to the uptake and accumulation of phosphorus in peanut seed kernel, and significantly reduced the distribution ratio of leaf, stem, root, gynophore and fruit shell. The cultivation of plastic film increased the uptake of phosphorus of plant and decreased the phosphorus distribution ratio of stem. Potassium accumulation and distribution rate in seed kernel of peanut increased under calcium application and film mulching cultivation. The synergistic relationship between total calcium accumulation and total nitrogen accumulation (the coefficient of determination R2 = 0.7837) was better than that of total calcium accumulation and potassium and phosphorus accumulation (the coefficient R2 = 0.6591, 0.2019). The production efficiency (PE) and harvest index (HI) of nitrogen, phosphorus and potassium were increased by increasing calcium fertilizer. N, P, K requirement for 100kg pods of Ca750-OF treatment compared with Ca0-OF treatment saved 3.17 to 4.04kg, 0.27-0.30kg, 2.65 to 3.41kg, respectively. Therefore, the amount of nitrogen, phosphorus and potassium fertilizer could be reduced by application of calcium fertilizer in peanut production, which was beneficial for achieving higher yield and greater cultivation efficiency of peanuts.
To optimize the phosphorus (P) and organic fertilizer for peanut production in peanut growing regions of southern Henan province, the field experiment was conducted to study the effect of different phosphorus rates (45 kg/hm2, 90 kg/hm2 and 135 kg/hm2) and organic fertilizer rates (0.75 t/hm2, 1.50 t/hm2 and 2.25 t/hm2) on peanut yield, phosphorus uptake by peanut, soil phosphorus fractions and soil phosphatase activity. The results showed that, under the same P rates, compared with 2.25 t/hm2 organic fertilizer rates, the yield was significantly higher at 0.75 t/hm2、1.50 t/hm2 organic fertilizer rates, but lower for the shoot dry matter weight; under the same organic fertilizer rates, increasing P rates significantly increased shoot biomass, but with no significant effect on peanut yield. The responses of P content in different parts of peanut to P and organic fertilizer were as following: medium and high amounts of P and organic fertilizer treatments were significantly higher than those of low amount of P and organic fertilizer treatments, while the effect of medium and high amount of P and organic fertilizer varied with plant parts. Response of soil phosphorus fractions to P and organic fertilizer were different, including labile-P (H2O-P and NaHCO3-Pi) and the moderately labile-P (NaOH-Pi and NaOH-Po) content increased significantly with increasing P and organic fertilizer, but having no significant difference for stable-P (Residual-P and HCl-P). The effect of organic and P fertilizer on soil phosphatase activity were also different, increasing organic fertilizer significantly improved soil phosphatase activity; however, increasing P fertilizer showed the opposite trend. In conclusion, reasonable integrated use of P and organic fertilizer significantly improved peanut yield, peanut P content, labile soil P fractions content, and soil phosphatase activity; however, excessive P and organic fertilizer resulted in excessive vegetative growth, lower peanut yield, and no improvement in peanut P content. The combined application of 45 kg/hm2 P fertilizer and 0.75-1.50 t/hm2 organic cake fertilizer improved P uptake in peanut-soil system and peanut yield, which could be applied in peanut growing regions of southern Henan province.
WRKY transcription factors is the important member of plant signal transduction pathway, plays an important role in the process of plant resistance, in order to better understand BnWRKY70 in rapeseed blackleg disease resistance. The sequence of BnWRKY70 specific gene to response to blackleg was analyzed, and the 308 bp CDS specific section of BnWRKY70 gene cloned, using the Tobacco rattle virus carrier constructed induced gene silencing system of oilseed, then validated target gene expression quantity with qRT - PCR, finally evaluation resistance of BnWRKY70 gene silencing rape after inoculation of blackleg pathogens by phenotypic observation and statistical analysis of disease index. The results showed that BnWRKY70 gene had the longest ORF of 858 bp, encoding 285 amino acids, containing a WRKY conservative domain structure, belonging to the class Ⅲ WRKY transcription factors, and BnWRKY70 gene expression was significantly decreased after silence by successful VIGS system constructed in oilseed rape, the leaf of gene silencing oilseed rape is more susceptible than target gene silence oilseed rape, the disease spot area is larger, and the disease index was significantly higher than that of control. It all showed that the silence of BnWRKY70 genes decreased the oilseed rape resistance, to further reveal pathogen molecular interactions mechanism of oilseed rape.
Peanut scab caused by Elsinoë arachidis occurred widely in Liaoning Province and caused serious yield loss. The biological characteristics of E. arachidis were investigated to clarify the characteristics of the pathogen. The results showed that the colony morphology of E. arachidis on PSA appeared raised, wrinkled and grew slowly. The optimum medium for colony growth was PSA, best pH value was pH6, optimum temperature was 25℃ and grew well in darkness. The best carbon and nitrogen sources were galactose and yeast extract. The mycelia could not survive above 48℃ after 10min. The optimum temperature for conidial germination was 25℃, best pH value was 5. The best carbon and nitrogen sources were 1% dextrose, 1% alanine and 1% glycine. The conidia could not germinate above 47℃ after 10min.
Ceuthrrhynchus liupanensis is a kind of boring insect, and compensatory response can be induced by boring stress of Ceuthrrhynchus liupanensis . The oil-flax has developed an important mechanism to adapt the boring stress, but there is a lack of relevant research. We aim to reveal the compensation effect of oil-flax yield traits under the boring stress of Ceuthrrhynchus liupanensis . A plot experiment was conducted to study the relationship between compensation effect of oil-flax and pest damage in different pest population density and wounds simulation test. The regression model was established to simulate the compensatory effect of oil-flax by using field investigation and data validation and the population density ranges of Ceuthrrhynchus liupanensis. Results showed that compensative coefficient was the highest at 20/m2 , for 1000-seed weight, yield per plant and plot yield, the compensative coefficients were 17.74%, 24.62% and 26.97% respectively. The regression equation between damage index and 1000-seed weight was y=-0.1981x2+0.9029x+6.0766（R2=0.8090）, the regression equation between population density and damage index was y=0.0203x+0.4127（R2=0.9967）, regression equation between population density and yield was y=-0.0051x2+0.7277x+86.107（R2=0.8814）.The test of significance showed that measured value and theoretical value had no significant difference, the goodness of fit was better.
The response surface methodology of Box-Behnken is used to optimize oil extraction processing by subcritical fluid from rapeseed cold press cake. The quality of the oil and meal obtained is studied and compared with n-hexane extraction and supercritical CO2 extraction. The experiment result indicated that the effect of solvent ratio to material and extraction time on oil yield were more significant than extraction temperature. The interaction between extraction time and solvent ratio to material had a significant effect on oil yield. The optimum operation parameters of subcritical butane extraction were: solvent ratio to material 8.3mL/g, extraction time 90min and extraction temperature 35℃．Under this optimal condition, the oil yield was 95.10%. The subcritical butane extraction of rapeseed oil from cold press cake has a half of phosphorus contents, which was 113.20mg/kg, better acid and peroxide value compared to n-hexane extraction. The phosphorus content of rapeseed oil extracted by subcritical butane was significantly different from that of supercritical extraction oil, but the other quality indexes，such as acid value, peroxide value, sterol and tocopherol contents, were slightly different from that of supercritical extraction oil.
Brassica crops had the greatest economic value of Cruciferae. It included not only oil crops (B. napus and B. juncea), but also cruciferous vegetables, such as B. rapa, B. oleracea, B. juncea. Cytoplasmic male sterility (CMS), an important way to use heterosis, had been used efficiently for hybrid seed production in Brassica. In recent years, more than 10 different types of CMS had been reported in Brassicas. Mitochondrial genomes of most CMS systems had been sequenced. At present, great progress had been made on the function of genes responsible for CMS, mitochondrial genome sequencing and classification of cytoplasm. This paper summarized and prospected the sequencing and application of the mitochondrial genome of CMS cytoplasm types and the mechanism of different CMS reported in rapeseed. With the development of molecular biology and sequencing technologies, researches on classification of cytoplasm and the mechanism of CMS will help to identify and apply CMS in Brassica.
To investigate the function of rapeseed transcription factor FUS3 on fatty acids, CDS sequences of BnaA2.FUS3 and BnaA6.FUS3 (two copies of BnaFUS3 gene) were cloned from Brassica napus Xiangyou15?. Their CDS were 927 bp and 948 bp, encoded 309 and 315 amino acids. Amino acid sequence variation occurred in the C-terminal. Hydrophilic proteins BnaA2.FUS3 and BnaA6.FUS3 belong to B3 family, are membrane protein with no transmembrane region. Homology showed that both BnaA2.FUS3 and BnaA6.FUS3 were homologous genes of BraFUS3 and AtFUS3. Fluorescent relative quantitative analysis showed that BnaA2.FUS3 was expressed in roots, stems, leaves and horns, and was relatively stable in seeds. The expression peak appeared in pod skin at 25d after pollination. BnaA6.FUS3 was seed-specific and the expression peak appeared at 35d after pollination. Both expressions of BnaA2.FUS3 and BnaA6.FUS3 showed similar M-type in pod skin. The relationship between BnaFUS3 expression and accumulation of fatty acids in seed showed that, both expression BnaA2.FUS3 and BnaA6.FUS3 were rapidly increased at 30 d after pollination, when each fatty acid increased into a rapid period. They changed little at 45 to 50 d after pollination, and the fatty acid accumulation was also slowed down and became stable. This indicated that BnaFUS3 had important influence on embryogenesis and development, and played an important role in fatty acid synthesis and lipid accumulation.
To understand the genetic control of stem strength in Brassica napus, the ‘major gene and polygene mixed genetic model’ was used to analyze the stem strength trait of 6 generations (P1, P2, F1, B1:2, B2:2 and F2:3) in both MB and ZB hybrid combinations. Results indicated that stem strength genetic was fitted in MX2-ADI-ADI model, i.e., ‘2 pairs of additive-dominant-epistatic major gene plus additive-dominant-epistatic polygene’ model. Stem strength was mainly controlled by 2 major genes and the average heritability of major gene were 19.46% and 69.93% in MB and ZB combinations respectively. The additive effects and dominant effects of the 2 major genes were in opposite direction in MB combination, but in same direction in ZB combination. Moreover, multiple epistatic effects influenced the 2 major genes. Proportion of environmental variance to phenotypic variance in these 2 combinations were 54.68% and 13.23% respectively, meaning that environment factors had strong impact on stem strength in rapeseed.
