Pod Shattering Resistance Research Articles

Evaluation of the Effectiveness of Pod Sealants in Increasing Pod Shattering Resistance in Oilseed Rape (Brassica napus L.)

Shattering of pods of oilseed rape (Brassica napus L.) is a major cause of seed yield losses prior to and during harvesting. In order to reduce shattering, researchers have been engaged in the development of special preparations that are known as pod sealants (PS). Despite the fact that there are already developed and commercialized PSs that have only been effective on seed yield preservation under certain environmental conditions, there is still a need to create a more versatile and efficient PS. Currently, the most promising method of controlling pod shattering in oilseed rape is the application of our developed novel acrylic- and trisiloxane-based pod sealant (PS4). The effectiveness of PS4 and three commercial pod sealants (PS1, PS2, and PS3) was assessed in this comparative study. By spraying an oilseed rape crop with PS4, natural seed loss can be reduced by 20–70%, depending on the prevailing weather conditions, and loss of seeds during harvest can be reduced by more than three-fold compared with that by the control treatment. Thus, the overall results demonstrated that by applying a novel pod sealant (PS4) to oilseed rape crops 2 weeks before harvest can increase the net profit margin by €30–€150 ha−1. The life cycle assessment showed that during 2014–2016 oilseed rape cultivation, the largest effect on global warming emission (kg CO2 eq) reduction was experimental sealant PS4, i.e., approximately 17% compared to the control.

Genetic variability of soybean (Glycine max L. Merrill) genotypes for pod shattering resistance

Consumer demand for soybean (Glycine max L. Merrill) is not only high yielding variety, but also must be in accordance with industrial preferences, primarily for its shattering resistance. A total of 16 soybean lines were evaluated in Nganjuk, East Java, Indonesia from Feb to May 2018. The pod shattering evaluation was using oven-dry method. All tested lines have large seed size, except SAT-Ng-A4. Five lines have early days to maturity (< 80 d). The highest yielding line and large seeded size was SAT-Ng-AG-3 (4.06 t ha-1), but it has medium maturity. Pod shattering evaluation which using a gradient system of temperature showed that oven temperature of 50 °C and 60 °C were able to differentiate the soybean resistance to pod shattering. Three very resistant lines and one resistant line were obtained after exposed to 60 °C. The soybean pods which allowed to dry at room temperature for 9 d and exposed to high temperature (80 °C) showed high variability on shattering resistance. Three resistant lines (SAT-Ng-A4, SAT-Ng-6-13, and SAT-Ng-5-5) were obtained from screening on both oven methods. Those three lines with high yield, large seed size, and medium maturity can be used as parental lines to improve soybean shattering resistance in the breeding program.

CRISPR/Cas9-mediated genome editing reveals differences in the contribution of INDEHISCENT homologues to pod shatter resistance in Brassica napus L.

The INDEHISCENT (IND) and ALCATRAZ (ALC) gene homologues have been reported to be essential for dehiscence of fruits in Brassica species. But their functions for pod shatter resistance in Brassica napus, an important oil crops, are not well understood. Here, we assessed the functions of these two genes in rapeseed using CRISPR/Cas9 technology. The induced mutations were stably transmitted to successive generations, and a variety of homozygous mutants with loss-of-function alleles of the target genes were obtained for phenotyping. The results showed that the function of BnIND gene is essential for pod shatter and highly conserved in Brassica species, whereas the BnALC gene appears to have limited potential for rapeseed shatter resistance. The homoeologous copies of the BnIND gene have partially redundant roles in rapeseed pod shatter, with BnA03.IND exhibiting higher contributions than BnC03.IND. Analysis of data obtained from the gene expression and sequence variations of gene copies revealed that cis-regulatory divergences alter gene expression and underlie the functional differentiation of BnIND homologues. Collectively, our results generate valuable resources for rapeseed breeding programs, and more importantly provide a strategy to improve polyploid crops.

Evaluasi Ketahanan Galur Harapan Kedelai terhadap Pecah Polong dan Keragaan Karakter Agronomi yang Sesuai untuk Iklim Tropis

Jurnal Biologi Indonesia diterbitkan oleh Perhimpunan Biologi Indonesia. Jurnal ini memuat hasil penelitian ataupun kajian yang berkaitan dengan masalah biologi yang diterbitkan secara berkala dua kali setahun.

Molecular Diversity Analysis and Genetic Mapping of Pod Shatter Resistance Loci in Brassica carinata L.

Seed lost due to easy pod dehiscence at maturity (pod shatter) is a major problem in several members of Brassicaceae family. We investigated the level of pod shatter resistance in Ethiopian mustard (Brassica carinata) and identified quantitative trait loci (QTL) for targeted introgression of this trait in Ethiopian mustard and its close relatives of the genus Brassica. A set of 83 accessions of B. carinata, collected from the Australian Grains Genebank, was evaluated for pod shatter resistance based on pod rupture energy (RE). In comparison to B. napus (RE = 2.16 mJ), B. carinata accessions had higher RE values (2.53 to 20.82 mJ). A genetic linkage map of an F2 population from two contrasting B. carinata selections, BC73526 (shatter resistant with high RE) and BC73524 (shatter prone with low RE) comprising 300 individuals, was constructed using a set of 6,464 high quality DArTseq markers and subsequently used for QTL analysis. Genetic analysis of the F2 and F2:3 derived lines revealed five statistically significant QTL (LOD ≥ 3) that are linked with pod shatter resistance on chromosomes B1, B3, B8, and C5. Herein, we report for the first time, identification of genetic loci associated with pod shatter resistance in B. carinata. These characterized accessions would be useful in Brassica breeding programs for introgression of pod shatter resistance alleles in to elite breeding lines. Molecular markers would assist marker-assisted selection for tracing the introgression of resistant alleles. Our results suggest that the value of the germplasm collections can be harnessed through genetic and genomics tools.

Identification of Soybean Genotypes for Pod Shattering Resistance Associated with Agronomical and Morphological Characters

&lt;p&gt;A yield loss caused by pod shattering is one of the obstacles to the improvement of soybean productivity in tropical areas. The aim of this study was to identify the resistance of soybean genotypes to pod shattering as affected by agronomical and morphological characters. The field study was conducted in Malang, Indonesia, using 150 soybean genotypes. Data were collected on agronomical traits, the percentage of pod shattering, and pod morphological traits. Screening for shattering resistance was done as per oven dry method. Percentage of pod shattering was ranged from 0 % up to 100 % shattering with a mean of 58.11 %. Pod shattering was found to be negatively correlated with a number of pod per plant, the thickness of the pod, and Y/Z (seed weight and pod weight ratio). The screening obtained 66 very highly susceptible genotypes, 19 susceptible genotypes, 19 moderate genotypes, 38 resistant genotypes, and 8 very resistant genotypes. Two of eight very resistant genotypes (G511H/Anj//Anj///Anj////Anj-6-11 and G511H/Anj//Anj///Anj////Anj-5-4) have high yield, medium maturity day and large seed size. Those lines could be used as gene donor for soybean varietal improvement for shattering resistance, and recommended to propose as new improved soybean varieties resistant to pod shattering in Indonesia.&lt;/p&gt;

Molecular tagging of pod shattering tolerance trait in soybean[Glycine max (L.) Merrill] genotype MACS-450.

Pod shattering (Dehiscence) severely reduces seed yield in soybean. Molecular tagging of pod shattering resistance can help in the process of breeding for shattering tolerance. In this study, an segregating population of cross (susceptible cultivar Monetta x tolerant genotype MACS-450) was used for bulked segregant analysis (BSA) with 26 SSR (simple sequence repeat) primers known to amplify markers linked to 22 qPDH loci. Among them, eight polymorphic SSR markers, viz., Sat_350 (qPDH1-7), Satt185 (qPDH1-3), Satt674 (qPDH1-5 loci), Satt166 (qPDH3-5), SRM1 (qPDH1 loci) Sat_342 (qPDH3-2), Satt685 (qPDH1-2) and Sat_407 (qPDH3-1) were able to distinguish parents differing for pod shattering of them two primers Satt 166 and SRM1 yielded markers polymorphic in between shattering tolerant and susceptible bulks by amplifying only Satt166-200 bp marker and SRM1-234bp marker only in tolerant bulks. Only Satt166-200 bp marker was observed in tolerant parent, bulks and 14 plants; while another 237 bp marker for pod shattering susceptibility got amplified in 46 plants including 8 plants that were heterozygous for both alleles. SRM1-234 bp marker was observed only in tolerant parent, bulks and 15 plants; while another 237 bp marker for pod shattering susceptibility got amplified in 45 plants. In combined marker analysis, the markers Satt 166 (qPDH3-5 loci) and SRM1 (qPDH1 loci) were linked with pod shattering score and were also confirmed in individual 60 F2 segregants. Hence, these markers could be utilized in the marker assisted for pod shattering resistance/tolerance breeding of qPDH3-5 like and qPDH1 genes.

Variability on morphological characters associated with pod shattering resistance in soybean

Abstract. Krisnawati A, Adie MM. 2016. Variability on morphological characters associated with pod shattering resistance in soybean. Biodiversitas 17: 73-77. Pod shattering is one of the major constraint associated with soybean production during dry season in Indonesia. The objectives of the study were to investigate varietal difference of pod shattering and to identify the morphological pod characters related to pod shattering. The field study was carried out in Blitar (East Java, Indonesia) during the dry season 2015. Morphological traits of pod were studied for their association with pod shattering trait in 30 soybean genotypes. The results showed significant differences between genotypes for all characters studied. The degree of shattering varied among genotypes with shattering percentage ranging from 2.5% (G511H/Argom//Argom-2-1) to 100% (Grobogan) with mean of 30%.However, among the 30 genotypes studied, 13 genotypes were relatively resistant, 11 genotypes moderate, 1 genotype susceptible, and 5 genotypes were very highly susceptible. Further path coefficient analysis indicated direct effects of the pod wall thickness and pod length on shattering percentage while other causal effects were small. These characters (pod wall thickness and pod length) may play role as determinant factors in pod shattering resistance. Therefore, soybean resistance to pod shattering could be enhanced by increasing thickness of the pod wall. &#x0D; Keywords: Glycine max, pod characteristics, pod shattering, resistance

Multigenic Control of Pod Shattering Resistance in Chinese Rapeseed Germplasm Revealed by Genome-Wide Association and Linkage Analyses.

The majority of rapeseed cultivars shatter seeds upon maturity especially under hot-dry and windy conditions, reducing yield and gross margin return to growers. Here, we identified quantitative trait loci (QTL) for resistance to pod shatter in an unstructured diverse panel of 143 rapeseed accessions, and two structured populations derived from bi-parental doubled haploid (DH) and inter-mated (IF2) crosses derived from R1 (resistant to pod shattering) and R2 (prone to pod shattering) accessions. Genome-wide association analysis identified six significant QTL for resistance to pod shatter located on chromosomes A01, A06, A07, A09, C02, and C05. Two of the QTL, qSRI.A09 delimited with the SNP marker Bn-A09-p30171993 (A09) and qSRI.A06 delimited with the SNP marker Bn-A06-p115948 (A06) could be repeatedly detected across environments in a diversity panel, DH and IF2 populations, suggesting that at least two loci on chromosomes A06 and A09 were the main contributors to pod shatter resistance in Chinese germplasm. Significant SNP markers identified in this study especially those that appeared repeatedly across environments provide a cost-effective and an efficient method for introgression and pyramiding of favorable alleles for pod shatter resistance via marker-assisted selection in rapeseed improvement programs.

Rapeseed research and production in China

Rapeseed (Brassica napus L.) is the largest oilseed crop in China and accounts for about 20% of world production. For the last 10years, the production, planting area, and yield of rapeseed have been stable, with improvement of seed quality and especially seed oil content. China is among the leading countries in rapeseed genomic research internationally, having jointly with other countries accomplished the whole genome sequencing of rapeseed and its two parental species, Brassica oleracea and Brassica rapa. Progress on functional genomics including the identification of QTL governing important agronomic traits such as yield, seed oil content, fertility regulation, disease and insect resistance, abiotic stress, nutrition use efficiency, and pod shattering resistance has been achieved. As a consequence, molecular markers have been developed and used in breeding programs. During 2005–2014, 215 rapeseed varieties were registered nationally, including 210 winter- and 5 spring-type varieties. Mechanization across the whole process of rapeseed production was investigated and operating instructions for all relevant techniques were published. Modern techniques for rapeseed field management such as high-density planting, controlled-release fertilizer, and biocontrol of disease and pests combined with precision tools such as drones have been developed and are being adopted in China. With the application of advanced breeding and production technologies, in the near future, the oil yield and quality of rapeseed varieties will be greatly increased, and more varieties with desirable traits, especially early maturation, high yield, high resistance to biotic and abiotic stress, and suitability for mechanized harvesting will be developed. Application of modern technologies on the mechanized management of rapeseed will greatly increase grower profit.

Screening of M3 mutants for yellow vein mosaic virus resistance in greengram [Vigna radiata (L.) wilczek

Greengram [ Vigna radiata (L.) Wilczek] is a cheap source of dietary protein for the poor, with high levels of folate and iron compared with many other legumes. Mungbean yellow mosaic virus is also one of the destructive viral disease affecting yield potential of greengram both quantitatively and qualitatively. Induced mutations, have offered a single and short alternative to conventional breeding including isolation, screening, selection and testing generation after generation. An investigation was carried out in two mungbean genotypes viz., CO (Gg) 7 and NM 65 treated by two mutagens viz., gamma rays at the doses of 300, 400 and 500 Gy and EMS treatments of 10, 20 and 30 mM. The trial was conducted in the research farm of Agricultural College and Research Institute, TNAU, Madurai during Kharif season 2013. The M 2 generation was raised as individual M 1 plant basis. The treated and control populations of M 2 generation were carefully screened for pod shattering resistance. The yellow vein mosaic virus disease (YMV) incidence was recorded for all the plants in M 3 generation for the selected 22 mutants. Based on field scoring, the mutants viz., M 5 , M 18 , M 26 , M 46 , M 54 , M 58 , M 70 , M 71 , M 92 and M 98 were identified as yellow vein mosaic virus resistant mutants. The mutants which showed field resistance were checked for YMV resistant gene using the gene specific primer ISSR811. Five mutants confirmed with marker studies. These resistant mutants have been forwarded to next generation for further yield performance.

Physiological Mechanisms behind Differences in Pod Shattering Resistance in Rapeseed (Brassica napus L.) Varieties.

Pod shattering resistance index (SRI) is a key factor affecting the mechanical harvesting of rapeseed. Research on the differences in pod shattering resistance levels of various rapeseed varieties can provide a theoretical basis for varietal breeding and application in mechanical harvesting. The indicators on pod shattering resistance including pod morphology and wall components were evaluated on eight hybrids and open pollinators, respectively, during 2012–2014. The results showed the following: (1) From the current study, SRI varied greatly with variety, and conventional varieties had stronger resistance than hybrid according to the physiological indexes. and (2) Under the experimental conditions, the SRI was linearly related to pod wall weight and the water content in pod walls, and the goodness-of-fit measurements for the regression model of the SRI based on pod wall weight and water content were 0.584** and 0.377*, respectively, reaching the significant level. This illustrated that pod wall weight and the water content in pod walls determined the SRI. (3) Compared with the relative contents of biochemical components in pod walls, the contents of particular biochemical components in pod walls had closer correlations with SRI. Among the biochemical components, the hemicellulose content was the decisive factor for the SRI.

The basis of pod dehiscence: anatomical traits of the dehiscence zone and expression of eight pod shatter-related genes in four species of Brassicaceae

Members of the Brassicaceae family disperse their seeds through a mechanism commonly referred to as fruit dehiscence or pod shatter. Pod shatter is influenced by variations in valve margin structure and by the molecular control pathways related to valve development. Anatomical patterns of the dehiscence zone from Brassica napus L., Brassica rapa L., Brassica carinata L., and Sinapis alba L., representing fruit types differing in pod shatter resistance, were compared using histological staining. The pod shatter-susceptible plant B. napus showed an increased lignin deposition at the vascular bundle of the replum as well as an increased separation of cell layers. In pod shatter-resistant plants S. alba, B. rapa, and B. carinata, we observed two layers of lignified valve margin cells. From these four species, we isolated and identified homologs of SHATTERPROOF (SHP1, SHP2), INDEHISCENT (IND), ALCATRAZ (ALC), FRUITFULL (FUL), AGAMOUS (AG), NAC SECONDARY WALL THICKENING PROMOTING FACTOR1 (NST1), and SEEDSTICK (STK) genes involved in fruit development and pod shatter in Arabidopsis. Transcriptional analysis of these eight genes was performed by real-time polymerase chain reaction and the results demonstrate that differences in the expression patterns of the eight genes may be associated with dehiscence variation within these four species.

A large replum-valve joint area is associated with increased resistance to pod shattering in rapeseed

The structure of the replum was studied in 64 rapeseed lines and in an F2 population derived from a cross between a high pod shattering resistance line, zy72360, and a susceptible line, R1. The dimensions of the replum close to the pedicel in lines with high silique shattering resistance index (SSRI) were greater than those with low SSRI. The replum-valve joint area index (RJAI) was used to investigate the relationship between the replum size and pod shattering. In the 64 accessions, RJAI displayed wide variation (0.50-4.12 mm(2)), with a variance coefficient of 45.4%. There were highly significant positive correlations between SSRI and RJAI, with a correlation coefficient of 0.6140. Analysis of RJAI in 276 F2 individuals further validated the positive correlations between SSRI and RJAI. These results revealed that replum structure was highly associated with pod shattering, and that a thick replum structure could produce high pod shatter resistance. The replum-valve joint area offers a good method to screen high resistance materials beneficial for breeding.

Paclobutrazol increases canola seed yield by enhancing lodging and pod shatter resistance in Brassica napus L.

This 2-year field study investigated the effects of time and paclobutrazol concentration on the seed yield and the lodging and pod shatter resistance of oilseed rape (Brassica napus L.). Paclobutrazol was sprayed on the foliar tissue of two rapeseed cultivars, Yangguang 2009 and Fengyou 520, at the closed canopy stage and the early bud stage at concentrations of 0, 150 and 300mgL−1. Our results demonstrated the following: (1) Paclobutrazol significantly increased lodging resistance, pod shatter resistance. Paclobutrazol reduced the number of seeds per pod but increased the number of pods per plant, the 1000-seed weight and the yield. With increasing paclobutrazol concentrations, the resistance to lodging and pod shattering increased, whereas the increment in yield decreased. Compared with treatment at the early bud stage, the application of 150mgL−1 paclobutrazol at the closed canopy stage significantly enhanced the lodging and pod shatter resistance and increased the yield increment in both cultivars. (2) After treatment with paclobutrazol, the increment of lodging resistance and pod shatter resistance were higher for Fengyou 520 than for Yangguang 2009, and the yield increment was less. (3) The increased root-top ratio, increased snapping resistance and reduced plant height resulting from paclobutrazol treatment reduced the angle of plant lodging, which improved the ability of the culm to resist lodging. Pod shatter resistance increased as pod water content and pod dry weight increased. In summary, 150mgL−1 of paclobutrazol sprayed on foliar tissue at the closed canopy stage significantly enhanced lodging resistance, pod shatter resistance and yield. These improvements could help augment the mechanical production of rapeseed in China.

Expression divergence of FRUITFULL homeologs enhanced pod shatter resistance in Brassica napus.

To improve pod shatter resistance in the important oilseed crop Brassica napus, the phenotypic diversity of B. napus was tested using 80 B. napus varieties for pod shatter resistance by a random impact test. Among these varieties, R1-1 was identified as resistant, while R2, 8908B was susceptible to shatter. To understand the molecular basis for this phenotypic difference based on the candidate gene approach, B. napus FRUITFULL (FUL) homologs were identified and characterized. Two FUL loci in the A and C genomes of B. napus were identified. In the susceptible variety, both BnaA.FUL and BnaC.FUL were expressed in the same tissues. However, the expression level of BnaC.FUL differed in varieties with different pod shatter resistance. In the most resistant variety, R1-1, only BnaA.FUL was expressed, while BnaC.FUL was silenced. Therefore, the functional divergence and differing expression of BnaX.FUL homeologs may significantly affect phenotypic variation, which is an important consequence of allopolyploid evolution. This expression level divergence may be useful for selecting pod shatter resistant lines through marker-assisted selection in B. napus-breeding programs.

Pod shattering resistance associated with domestication is mediated by a NAC gene in soybean

Loss of seed dispersal is a key agronomical trait targeted by ancient human selection and has been regarded as a milestone of crop domestication. In this study, in the legume crop soybean Glycine max (L.) Merr. which provides vegetable oils and proteins for humans, we show that the key cellular feature of the shattering-resistant trait lies in the excessively lignified fibre cap cells (FCC) with the abscission layer unchanged in the pod ventral suture. We demonstrate that a NAC (NAM, ATAF1/2 and CUC2) gene shattering1-5 (SHAT1-5) functionally activates secondary wall biosynthesis and promotes the significant thickening of FCC secondary walls by expression at 15-fold the level of the wild allele, which is attributed to functional disruption of the upstream repressor. We show that strong artificial selection of SHAT1-5 has caused a severe selective sweep across ~ 116 kb on chromosome 16. This locus and regulation mechanism could be applicable to legume crop improvement.

Combining Ability and Breeding Potential of Rapeseed Elite Lines for Pod Shatter Resistance

Pod shatter resistance of rapeseed is of great importance for modern farming practice. In order to determine the combining ability of elite inbred lines and the breeding potential of rapeseed hybrids in terms of pod shatter resistance, analysis of a 6×6 incomplete diallel cross was conducted at two locations. Results showed that a significant variation existed among breeding lines and their F1 hybrids for pod shatter resistant index (SRI), pod length and width. Pod shatter resistance was significantly positively correlated with pod length. The general combining ability (GCA) effects (GCA=1.58) played a more important role than specific combining ability (SCA) effects (SCA=0.20) for pod shatter trait. The elite lines R1, 1019B and 1055B displayed significant positive GCA effects for pod shatter resistance. Four crosses (1019B×R1, 1015B×R1, 6098B×R1, and 8908B×R1) with high mean performance and positive SCA effects were recommended for developing new hybrids for mechanical harvest in the middle reaches of the Yangtze River.

Discovery of Pod Shatter-Resistant Associated SNPs by Deep Sequencing of a Representative Library Followed by Bulk Segregant Analysis in Rapeseed

BackgroundSingle nucleotide polymorphisms (SNPs) are an important class of genetic marker for target gene mapping. As of yet, there is no rapid and effective method to identify SNPs linked with agronomic traits in rapeseed and other crop species.Methodology/Principal FindingsWe demonstrate a novel method for identifying SNP markers in rapeseed by deep sequencing a representative library and performing bulk segregant analysis. With this method, SNPs associated with rapeseed pod shatter-resistance were discovered. Firstly, a reduced representation of the rapeseed genome was used. Genomic fragments ranging from 450–550 bp were prepared from the susceptible bulk (ten F2 plants with the silique shattering resistance index, SSRI <0.10) and the resistance bulk (ten F2 plants with SSRI >0.90), and also Solexa sequencing-produced 90 bp reads. Approximately 50 million of these sequence reads were assembled into contigs to a depth of 20-fold coverage. Secondly, 60,396 ‘simple SNPs’ were identified, and the statistical significance was evaluated using Fisher's exact test. There were 70 associated SNPs whose –log10 p value over 16 were selected to be further analyzed. The distribution of these SNPs appeared a tight cluster, which consisted of 14 associated SNPs within a 396 kb region on chromosome A09. Our evidence indicates that this region contains a major quantitative trait locus (QTL). Finally, two associated SNPs from this region were mapped on a major QTL region.Conclusions/Significance70 associated SNPs were discovered and a major QTL for rapeseed pod shatter-resistance was found on chromosome A09 using our novel method. The associated SNP markers were used for mapping of the QTL, and may be useful for improving pod shatter-resistance in rapeseed through marker-assisted selection and map-based cloning. This approach will accelerate the discovery of major QTLs and the cloning of functional genes for important agronomic traits in rapeseed and other crop species.

Identification of QTLs involved in pod-shatter resistance in Brassica napus L.

Seed loss caused by pod-shatter during harvesting is one of the main problems in rapeseed production worldwide. Quantitative trait loci (QTLs) for pod-shatter based on genetic mapping would help breeders develop cultivars resistant to pod-shatter. In this study, we constructed a genetic map of Brassica napus containing 107 simple sequence repeat (SSR) markers and 68 sequence-related amplified polymorphism (SRAP) markers using a doubled-haploid (DH) population of 276 lines derived from the cross H155 × Qva. This map covered 1382.8 cM with an average marker interval of 7.9 cM. In total, 13 QTLs for pod-shatter resistance were identified in this DH population at two experimental sites (in Wuhan and Zhengzhou); three of the QTLs were present at both locations. At Zhengzhou, nine QTLs, identified in linkage groups A1, A7, A8, C5, and C8, together explained 49.0% of the phenotypic variation. At Wuhan, four QTLs were mapped on the A1, A4, A7, and C8 linkage groups. These QTLs explained 38.6% of the phenotypic variation. These results may serve as a valuable basis for further molecular dissection of pod-shatter resistance in B. napus, and for development of the markers related to QTLs that may be useful for marker-assisted selection of pod-shatter resistant cultivars.