Development of a KASP Marker on Chromosome A05 for Seed Oil Content of Brassica napus

In order to identify the molecular markers that can be widely used in the breeding of Brassica napus L.varieties with high seed oil content under different genetic backgrounds,we developed a Kompetitive Allele Specific PCR(KASP)marker for seed oil content on the basis of the results from available studies.The verification in the F_(2) population showed that the marker was closely linked to the quantitative trait locus(QTL)for oil content on chromosome A05.The findings helped to breed the‘Fengyou’varieties with high seed oil content in the middle reaches of the Yangtze River.

Biotechnology ofα-linolenic acid in oilseed rape(Brassica napus)using FAD2 and FAD3 from chia(Salvia hispanica)

α-Linolenic acid(ALA,18:3Δ9,12,15)is an essential fatty acid for humans since it is the precursor for the biosynthesis of omega-3 long-chain polyunsaturated fatty acids(LC-PUFA).Modern people generally suffer from deficiency of ALA because most staple food oils are low or lack ALA content.Biotechnological enrichment of ALA in staple oil crops is a promising strategy.Chia(Salvia hispanica)has the highest ALA content in its seed oil among known oil crops.In this study,the FAD2 and FAD3 genes from chia were engineered into a staple oil crop,oilseed rape(Brassica napus),via Agrobaterium tumefaciens-mediated transformation of their LP4-2A fusion gene construct driven by the seed-specific promoter P_(NapA).In seeds of T0,T1,and T2 lines,the average ALA contents were 20.86,23.54,and 24.92%,respectively,which were 2.21,2.68,and 3.03 folds of the non-transformed controls(9.42,8.78,and 8.22%),respectively.The highest seed ALA levels of T0,T1,and T2 plants were 38.41,35.98,and 39.19%respectively,which were 4.10-4.77 folds of the respective controls.FA-pathway enzyme genes(BnACCD,BnFATA,BnSAD,BnSCD,BnDGAT1,BnDGAT2,and BnDGAT3)and positive regulatory genes(BnWRI1,BnLEC1,BnL1L,BnLEC2,BnABI3,BnbZIP67,and BnMYB96)were all significantly up-regulated.In contrast,BnTT1,BnTT2,BnTT8,BnTT16,BnTTG1,and BnTTG2,encoding negative oil accumulation regulators but positive secondary metabolism regulators,were all significantly down-regulated.This means the foreign ShFAD2-ShFAD3 fusion gene,directly and indirectly,remodeled both positive and negative loci of the whole FA-related network in transgenic B.napus seeds.

Physiological Differences Between Yellow-Seeded and Black-Seeded Rapeseeds (Brassica napus L.) with Different Testa Characteristics During Artificial Ageing

Yellow-seeded rapeseed (Brassica napus L.) is a new kind of breeding resources with yellow color, increased oil and protein content and less unwanted crude fiber content due to the thinner and transparent testa compared with traditional black or brown-seeded rapeseed. To analyze the longevity of the yellow-seeded rapeseed during storage, the physiological differences between the yellow and black-seeded near-isogenic lines were studied by artificial ageing method. The testa rate, anthocyanin content and melanin content of yellow-seeded rapeseeds decreased by 20.1, 25.2, and 80.4% respectively than black-seeded rapeseed. During artificial ageing, the yellow-seeded rapeseed showed significantly different effect of ageing compared with the black-seeded, as demonstrated by faster deterioration with lower germination percentage, seed vigour index, reducing sugar and soluble protein contents than the black-seeded, as well as a drastic increase in electrical conductivity, malnodialdehyde (MDA) content and a rapid decrease in activities of antioxidant enzymes catalase (CAT) and superoxide dismutase (SOD). The results suggested that the transparent testa of the yellow-seeded rapeseed lost some abilities to protect the embryo against adverse environmental conditions and thus led to a poor storability.

A Comparative Study on the Quality Components Between Self Pollinated Seeds and Naturally Pollinated Seeds in Brassica napus L. in Sichuan Ecological Region

[ Objective] This study was to reveal the differences in crude fat and glucosinolates between self pollinated seeds and naturally pollinated seeds in Brassica napus in sichuan ecological region.. [ Method] Near-infrared spectroscopy method （NIRS） was employed to measure the quality components in self pollinated seeds and naturally pollinated seeds of 861 shares of Brassica napus from Sichuan ecological region. And correlation analysis and regression analysis were conducted based on the experimental data via SPSS （statistics package for social science）. [ Result] The contents of crude fat in the self pollinated seeds were commonly a higher than that in the naturally pollinated seeds at 0.01 significant level; while the contents of glucosinolates in the self pollinated seeds and the naturally pollinated seeds were insignificantly different. Both the correlation relationship and linear regression for the crude fat between the self pollinated seeds and naturally pollinated seeds reached the significant level. The regression equations for the contents of crude fat（y1 ） and glucosinolates（ y2 ） in the naturally pollinated seeds and of crude fat（ x1 ） and glucosinolates（ x2 ） in self pollinated seeds were respectively determined to be y1 = 16.844 ＋0.614x1 and y2 = -0.620 ＋ 1.017 x2. [ Conclusion] In Brassica napus breeding, crude fat in naturally pollinated seeds should be emphatically taken into account, meanwhile concurrently considering that in self pollinated seeds; while glucosinolates in both the self pollinated seeds and the naturally pollinated seeds must be simultaneously concerned.

Effects of Nitrogen Fertilizer Management on Biological Traits and Physiological Indexes at Seedling Stage and Yield of Directly-sown Rapeseed(Brassica napus L.)

Field experiments were carried out to study the effects of different nitroge- napplication rates and application times on biological traits and physiological indexes of directly-sown rapeseed （Brassica napus L.） at the seedling stage and investigate the relationship between these biological traits or physiological indexes at the seedling stage and yield, so as to provide scientific theoretical support for high yield and efficient fertilization management in production of winter rapeseed. Field trials were conducted in Chengdu plain of Sichuan Province under rice-rapeseed rotation system during the period of 2011-2012. The nitrogen application rate trial consisted of five nitrogen levels （0, 90, 180, 270 and 360 kg/hm2） and the nitrogen application time trial included NTl（single application as base fertilized）, NT2 （bottom application ＋one time of topdressing at seedling stage） and NT3 （bottom application＋two times of topdressing at seedling stage） under the same nitrogen rate （225 kg/hm2）. The results indicated that compared with no nitrogen application （NO） treatment, the in- crease of nitrogen fertilizer is beneficial to the increase of biological traits including plant height, green leaf number, leaf area index and dry weight of rapeseed at the seedling stage, the improvement of physiological indexes including total nitrogen content, chlorophyll content and soluble protein content of functional leaves, and the reduction of soluble sugar content. Nitrogen rate was linearly correlated with various biological traits at the seedling stage and physiological indexes including total nitro- gen content, chlorophyll content and soluble sugar content in functional leaves over- a/I, but in parabolic correlation with soluble protein content. Under the same nitrogen rate, NT2 treatment exhibited biological traits remarkably or significantly higher than NT1 treatment and NT3 treatment. The nitrogen application times were linearly cor- related with the physiological indexes of functional leaves at the seedling stage. The various biological traits and physiological index of functional leaves at the seedlings stage were in quadratic function parabolic correlation with seed yield, and the corre- lation was significant （P〈0.05）. Therefore, under the rice-rapeseed rotation system in Chengdu plain, the economic rational nitrogen rate is 180-225 kg/hm2, and the mode of bottom application ＋ one time of topdressing （NT2） is suitable.

BnaUBP15s positively regulates seed size and seed weight in Brassica napus

Brassica napus(B.napus)is a globally significant oilseed crop,making a substantial contribution to both human oil and livestock feed production.Enhancing seed weight is crucial for improving rapeseed yield;however,only a limited number of seed weight-related genes have been functionally validated in B.napus thus far.UBIQUITINSPECIFIC PROTEASE 15(UBP15)belongs to the ubiquitin protease pathway and plays a maternal role in prolonging seed development in Arabidopsis.The potential utilization of UBP15 for enhancing seed yield in B.napus has remained unexplored until now.In this study,we identified the orthologs of UBP15 in B.napus and investigated its functionality using the CRISPR-Cas9 system.We generated mutant plants with multiple editing types targeting Bnaubp15s and successfully isolated T-DNA-free homozygous mutant lines that exhibited edits across four homologs of BnaUBP15 in T2 generation plants.Our preliminary data demonstrated that mutation of BnaUBP15s significantly reduced seed size,seed weight,and plant height while noticeably increasing the number of primary branches.These findings not only provide crucial evidence for further elucidating the molecular mechanism underlying the regulation of seed weight and size by BnaUBP15s but also offer promising novel germplasm for enhancing plant architecture.

Mechanical Harvesting Effects on Seed Yield Loss,Quality Traits and Profitability of Winter Oilseed Rape (Brassica napus L.)

China is one of the most important rapeseed producing countries in the world. Effective mechanical harvesting time for decreasing harvesting loss of winter oilseed rape has been becoming a critical factor. An elite cultivar Zhongshuang 11 （Brassica napus L.） was employed in two rounds of field experiments from 2009 to 2011. Seeds were sown with machine, three combine harvesting times namely combine harvesting A, B, and C （CHA, CHB, and CHC） were designed and manual harvesting （MH） as control was performed at maturity. The harvesting treatments were determined according to color of pod and seed in the field. Seed yield loss and quality in different treatments were evaluated. Results showed that both seed yields and harvesting losses in 2009-2010 were higher than that in 2010-2011, whereas seed oil contents in 2010-2011 were higher than that in 2009-2010. The highest yield appeared in CHB, which was significantly higher than that in MH. Furthermore, harvesting loss in CHB were 50% that in MH. Seed oil content and chlorophyll exhibited no obvious difference between CHB and MH. Economic profit analysis demonstrated that mechanical sowing/combine harvesting （MS/CH） showed an input/output ratio of 1：1.6, and it was 1：1.2 in mechanical sowing/manual harvesting （MS/MH）. Labor-cost accounted for more than 70% of the total cost in MS/MH, which led to low profitability to a great extent. Our results suggested that CHB was the optimum harvesting time for winter oilseed rape along the Yangtze River.

Effects of B, Mo, Zn, and Their Interactions on Seed Yield of Rapeseed (Brassica napus L.)

A field experiment was conducted to study the effects of boron (B), molybdenum (Mo), zinc (Zn) and their interactions on seed yield and yield formation of rapeseed (Brassica napus L. var. Huashuang 4). Application of B fertilizer to a sandy soil increased the seed yield by 46.1% compared to the control and also created a considerably higher seed yield than the two treatments solely applying Mo and Zn fertilizers, which suggested that B was a main constraint for the seed yield of Huashuang 4 in this experiment. The effect of B fertilizer on the seed yield was attributed to an increase in the number of seeds per silique and siliques per plant. The combined application of B with Mo or Zn resulted in higher seed yield than the application of B, Mo or Zn alone, and the seed yield of the B+Mo+Zn treatment was the highest in all treatments, 68.1% above the control. Dry matter accumulation of seed followed a typical S-shaped curve and it was higher in plants supplied with B than in plants without B. A small but significant increase in the seed oil content and an improvement in the oil quality were also observed in all treatments compared with the control. These results suggested that optimal micronutrient application could provide both yield and quality advantages for rapeseed in poor soil.

The Relationship of Color Formation with Related Enzymes and Protein Contents in the Seedcoat of Oilseed Rape (Brassica napus)

Three pairs of near-isogenic lines with different genetic backgrounds of yellow-seededand black-seeded rape (Brassica napus L.) were used as experiment materials to study therelationship of color formation in the seedcoat with enzyme activity and protein contentin it. The results showed that with similar genetic backgrounds, phenylalanine ammonia-lyase (PAL) and polyphenol oxidase(PPO) activities in the black-seeded lines were muchhigher than in their yellow-seeded counterparts and maximum PAL activity in the seedcoatoccurred comparatively late while no significant difference was present in glutaminesynthetase (GS) between the two types of rape. The plants were treated with red light,blue light, p-hydroxybenzoic acid (a PAL inhibitor), polyvinylpyridoxal (a PPO inhibitor),urea (a protein synthesis promoter) or chloramphenicol (CM, a plastid protein synthesisinhibitor) during seed development. It is speculated that PAL may be primarily responsiblefor coloration in the yellow seed; PPO may be the main factor contributing to thedarkness of the testa of the black genotypes; and nitrogen assimilation is, probably, notdirectly related to the difference in protein content observed between yellow- andblack-seeded genotypes, which may be induced mainly by PAL.

Identification of a candidate QTG for seed number per silique by integrating QTL mapping and RNA-seq in Brassica napus L.

Seed number per silique(SNPS)is one of seed yield components in rapeseed,but its genetic mechanism remains elusive.Here a double haploid(DH)population derived from a hybrid between female 6Q006with 35–40 SNPS and male 6W26 with 10–15 SNPS was investigated for SNPS in the year 2017,2018,2019 and 2021,and genotyped with Brassica 60K Illumina Infinium SNP array.An overlapping major QTL(qSNPS.C09)explaining 51.50%of phenotypic variance on average was narrowed to a 0.90 Mb region from 44.87 Mb to 45.77 Mb on chromosome C09 by BSA-seq.Subsequently,two DEGs in this interval were detected between extreme individuals in DH and F_2populations by transcriptome sequencing at7 and 14 days after pollination siliques.Of which,BnaC09g45400D encoded an adenine phosphoribosyltransferase 5(APT5)has a 48-bp InDel variation in the promoter of two parents.Candidate gene association analysis showed that this InDel variation was associated with SNPS in a nature population of rapeseed,where 54 accessions carrying the same haplotype as parent 6Q006 had higher SNPS than103 accessions carrying the same haplotype as parent 6W26.Collectively,the findings are helpful for rapeseed molecular breeding of SNPS,and provide new insight into the genetic and molecular mechanism of SNPS in rapeseed.

Detection of new candidate genes controlling seed weight by integrating gene coexpression analysis and QTL mapping in Brassica napus L.

Seed weight is a component of seed yield in rapeseed(Brassica napus L.).Although quantitative trait loci(QTL)for seed weight have been reported in rapeseed,only a few causal quantitative trait genes(QTGs)have been identified,resulting in a limitation in understanding of seed weight regulation.We constructed a gene coexpression network at the early seed developmental stage using transcripts of 20,408 genes in QTL intervals and 1017 rapeseed homologs of known genes from other species.Among the 10 modules in this gene coexpression network,modules 1 and 2 were core modules and contained genes involved in source–flow–sink processes such as synthesis and transportation of fatty acid and protein,and photosynthesis.A hub gene SERINE CARBOXYPEPTIDASE-LIKE 19(SCPL19)was identified by candidate gene association analysis in rapeseed and functionally investigated using Arabidopsis T-DNA mutant and overexpression lines.Our study demonstrates the power of gene coexpression analysis to prioritize candidate genes from large candidate QTG sets and enhances the understanding of molecular mechanism for seed weight at the early developmental stage in rapeseed.

Effects of Heat Stress during Seed Filling Stage on Brassica napus Seed Oil Accumulation and Chlorophyll Fluorescence Characteristics

As global temperature rise,the threat of heat stress to rapeseed production is becoming more obvious.Exploring the response characteristics of two important biological pathways,oil accumulation and photosynthesis,to heat stress during B.napus seed filling is helpful in the genetic improvement of heat-tolerant rapeseed.The effects of heat stress on seed oil accumulation and chlorophyll fluorescence characteristics of 29 B.napus germplasms with different oil content and environmental sensitivity,including 6 rapeseed varieties which exhibited environmentsensitive/insensitive and with high,medium or low oil content,were tested by whole plant heat stress or the in vitro silique culture system.Both assay exhibited similar trend on oil content of the rapeseed germplasms.The heat effect on the chlorophyll fluorescence kinetic parameters F_(v)/F_(m),ETR and Y(Ⅱ)were also consistent.Heat stress significantly decreased oil content,although there was abundant genetic variation on heat tolerance among the genotypes.Correlation analysis showed that the decrease rate of F_(v)/F_(m) of silique heat-stressed B.napus developing seed was positive correlative to the decrease rate of mature seed oil content of the whole plant heat-stressed rapeseed(R=0.9214,P-value<0.01).Overall,the results indicated that heat stress inhibited oil accumulation and photosynthesis in B.napus developing seed.The decrease rate of chlorophyll fluorescence parameter F_(v)/F_(m) of heat-stressed developing seed could be used as the index of heat tolerant rapeseed identification.Further,two heat insensitive rapeseed varieties with high oil content were identified.

Genetic Diversity of Testa Pigments and RAPD Marker of Yellow-Seeded Rapeseed (Brassica napus L.)

14 yellow-seeded rapeseed lines (Brassia napus L.) from different genetic sources were used to analyze diversity of testa pigments content, oil and protein content, and RAPD markers. The results showed that the anthocyanin and melanin were the most important pigments in testa and their content were responsible for the variation in seed color ranging from orange to black yellow, 14 yellow-seeded lines could be classified into 3 groups: high anthocyanin content group with anthocyanin content over 2. 54 mg g-1 DW, the seed color was light yellow or orange; low pigments content group with low content of anthocyanin and melanin, the testa was transparent and the seed color was light yellow, greenish yellow or twany; high melanin content group with melanin content over 178. 4U(A290nm) , the testa was black, the seed color was black yellow. Oil content changed from 36.2% to 45. 5%, protein content from 21.1% to 27.7% , and the correlation analysis revealed that the oil content is highly significantly negatively correlated with the protein content. The cluster analysis showed that the extensive genetic variation existed among 14 yellow-seeded lines by using unweighted paired group method with arithmetic average (UPGMA) based on RAPD markers which were amplified with decamer primers, the genetic similarity among them ranged from 0. 25 to 0.909, and 14 yellow-seeded lines could put into 2 clusters corresponding to genome difference.

Effects of Boron Nutrition on ^45Ca Retranslocation and Distribution in Rape(Brassica napus L.)Cultivars

Using tracer techniques with the radioisotope 45Ca, the effects of boron supply from soil and nutrient solution on the retranslocation of 45Ca from leaves to other parts of rape plants were studied. Results indicated that only a small portion of foliar-applied 45Ca could be retranslocated to other parts of the rape plant. There was no pronounced effect of boron level in the soil on 45 Ca retranslocation. Increasing boron concentrations in the nutrient solution significantly reduced 45 Ca radioactivity in root and stem, but increased 45Ca uptake and 45 Ca translocation to the upper leaves of rape plants. It was suggested that45 Ca absorbed by newly developed roots was easily distributed to upper leaves of rape plants. Boron may alter distribution of calcium via its effect on root development or growth of newly developed roots.

SPAD chorophyll meter was suitable in nitrogen quick diagnosis,yield forecast and fertilization recommendation in rapeseed(Brassica napus L. )

Nitrogen （N） is one of the most important nutrients for oilseed rape （Brassica napus L . ） , but there is a lack of quick diagnosis and recommended fertilization. Three field experiments were con-ducted to seek the best diagnostic method and establish a fertilizer rate recommendation model. For ex-periment 1, six treatments as application N 0,90,180,240,300 and 400kg ha -1 were designed, and the general N nutrition diagnosis method as SPAD -502 chlorophyll meter, RQflex plus 10 nitrate reflectrom- eter and GreenSeeker - 505 spectrometer were used at eight leaf stage, tenth leaf stage and bolting stage of rape to determine the suitable nitrogen rapid diagnosis method and establish the model of yield forecast and N rate recommendation as topdressing. The experiment 2 was designed to validate the veracity of yield forecast model obtained from experiment 1. The experiment 3 was designed to test the accuracy of N rate recommendation model come from experiment 1. The results indicated that there is a preferable inter-relation between N application rates and rape yield for experiment 1 （ y = - 0. 0176x2 ＋ 11. 136x ＋797. 88 ,R2 =0. 9905 ＊ ＊ ） , which conform to the performance of yield variation with N application levels as shortage, appropriate and excessive rapeseed. For three diagnosis methods, nitrate reflectrometer could reflect rape N nutrition status to some extent, but which influenced by rapeseed physiological char-acteristics such as lower biomass at seedling stage and luxury absorption of N at bolting stage, and the re-liability and stability of diagnosis were inferior. Spectrometer is suitable for quick N nutrition diagnosis at bolting stage, but the stage of topdressing is too late to meet the demand of N support. SPAD meter could more suitable in quick N diagnosis of oilseed rapes since it could reflect rape N nutrition preferable, and it has some advantages such as the strong stability, easy measuring and lower cost in detection. By SPAD meter, model of yield forecast yforeCastyield =370. 517xSPAD value -13310.3 （x 〈42. 54） and recommended N rate yR_dedNrate =162.7-[（370.517xSPADTflliie- 13 10. 3 ）/10. 0617 - 76. 7398 ] （x〈42.54） were established. For experiment 2, the actual yield and forecast yield showed good correlation （y = 0. 5022 ＋2244. 3x, R2 =0. 7852 ＊ ） . For experiment 3 , the amount of topdressing N calculate from recommended N rate model were put forward, and the yield for different treatments had no significant difference. Total-ly ,SPAD chlorophyll meter could be used in quick N nutrition diagnosis, forecast yield and N recommen-dation of oilseed rape.

Brassinosteroids promote seed development and physiological maturity of oilseed rape (Brassica napus L.)

Long developmental stage and late harvest time of winter rapeseed (Brassica napus L.) have great negative effects on rice planting of rice-rapeseed farming system in China. Early maturity improvement of rapeseed is necessary. ‘Zhongshuang 11’, an elite winter rapeseed cultivar, was used in consecutive field experiments during 2010-2012. At initial flowering stage, plants were consecutively sprayed with 0.1 mg/L 2-4-Epibrassinolide(BR) for 3 d. Two hundred sampling pods from different plants were randomly collected to measure seed related indexes with a 4 d interval from 7 to 47 d after peak anthesis (DAPA).Seed color turned light brown at 31 or 35 DAPA after BR treatment, seed dry weight (DWT)was increased while seed moisture content (SMC) was decreased during seed development.DWT almost reached the maximum value when SMC was 33.20% at 31 DAPA in 2010-2011 and 35.29% at 35 DAPA in 2011-2012 growing season after BR treatment. Similarly,the maximum values of standard germination test (SGT), accelerated aging test (AAT)and cold test (CT) were observed at 31 or 35 DAPA after BR treatment respectively. The high yield and seed oil content appeared at 31 or 35 DAPA accompanied with rapid decrease in total non-structural carbohydrate (TNC) in stems and leaves. Our study indicated that BR application advanced maturity of winter rapeseed by 4 to 8 days.

甘蓝型油菜(Brassica napus L.)千粒重性状遗传体系分析

通过遗传差异较大的 2个甘蓝型油菜 (BrassicanapusL )纯系亲本组合 (HSTC14×宁油 7号 )衍生后代的世代家系群体分析 ,应用主基因 +多基因家系世代联合分离分析方法研究油菜千粒重的遗传体系。结果表明 ,甘蓝型油菜HSTC14×宁油 7号组合千粒重遗传体系系由一对主基因 +多基因构成 ,主基因中只有加性效应 (d =0 10 6 2 ) ,不存在显性效应 ;多基因存在加性 ([d]=0 2 2 2 8)和显性效应 ,但显性效应为负值 ([h]=- 0 2 80 0 )。表明该组合千粒重主要由主基因加性效应和多基因效应决定 ,但无杂种优势。F2∶3家系群体主基因遗传力为 83 39% ,多基因遗传力为 11 71%。HSTC14×宁油 7号组合千粒重的改良可能受主基因无显性效应 ,多基因显性效应为负值的制约。

锰胁迫对甘蓝型油菜Brassica napus L.种子活力和幼苗抗氧化系统的影响

用不同质量分数的锰溶液(0.2%,0.4%,0.8%和1.2%Mn2+)处理甘蓝型胜利油菜Brassica napuscv.Shengli,研究锰对其种子活力、幼苗细胞膜透性、脂质过氧化及抗氧化剂的影响.结果表明:锰胁迫降低了种子活力、幼苗抗坏血酸(Vc)质量分数、超氧化物歧化酶(SOD)和过氧化氢酶(CAT)活性,破坏了细胞膜的完整性,并使丙二醛(MDA)质量分数、脯氨酸(Pro)质量分数和过氧化物酶(POD)活性增加.

甘蓝型油菜（Brassica napus L．）的春化作用及其应用

研究了甘蓝型春性、半冬性和冬性油菜（ＢｒａｓｓｉｃａｎａｐｕｓＬ．）春化时间，不同设备条件和不同生长阶段的春化效果，以及人工春化技术的利用，结果表明春性油菜的开花株率不受春化处理时间的影响，半冬性和冬性油菜的开花株率与春化处理时间有关．半冬性和冬性油菜的萌芽种子在春化室内通过春化阶段，分别需时２０ｄ和４５ｄ；冬性油菜在冰箱冷藏室通过春化阶段需时５０ｄ；三叶期冬油菜通过春化阶段需时３５ｄ．冬油菜在春化室的春化效果比冰箱冷藏室的效果好．适当延长春化时间能提高春化效果。延长每天光照时间能加快油菜的生育进程．利用冰箱冷藏室和生长室可以在上海当地完成半冬性和冬性油菜的春化和夏繁工作。

油菜(Brassicanapus L.)千粒重性状主位点组遗传分析

应用作物数量性状QTL体系的主位点组检测方法分析不同遗传来源的 12个甘蓝型油菜(BrassicanapusL. )亲本的千粒重性状的遗传差异类型、主位点组基因型和基因效应。结果表明: 12个甘蓝型油菜亲本间千粒重性状受 3个主位点组基因控制,各主位点组基因效应的方向、大小不等。3个主位点组基因的加性效应 (dM )分别为0 316 3**、-0 141 9*和-0 003 7; 3个主位点组基因的显性效应(hM)分别为-0 033 7、0 184 3*和-0 212 9*。主位点组基因加性效应(dM)的和为正值;显性效应(hM)的和为负值。主位点组遗传变异百分率为 54 44%,微位点组的遗传变异百分率为 33 26%。文中讨论了亲本和亲本间杂种千粒重性状的遗传特点和改良潜力。