Characterisation of post harvest shelf life in broccoli. Emma Skipper, Vicky Buchanan-Wollaston and David Pink. Warwick HRI, University of Warwick, Wellesbourne, Warwick, CV35 9EF, UK. Introduction: Broccoli (Brassica oleracea var italica) is a popular green vegetable consumed as a part of a healthy diet. Broccoli has a high vitamin and mineral content and contains health promoting properties such as antioxidants, flavonoids and glucosinolates. However broccoli has a notorious short shelf life displaying rapid senescence after harvest. Characteristics of a poor quality broccoli include a yellow appearance due to chlorophyll degradation, loss of flavour, reduced nutritional content and wilting as a result of a turgor loss, causing a high level of waste for retailers and consumers. The overall aim of this project is to investigate the effects of genetics on the gene expression and metabolite content of broccoli florets, to improve the shelf life of broccoli. Previous studies using double haploid (DH) lines as a mapping population to measure yellowing using colour charts and chromameter readings has located 9 QTLs relating to bud yellowing. Project Aims: To improve the existing linkage map for the trait bud yellowing by incorporating more markers onto the linkage map. To identify one major QTL accounting for the majority of the variation in shelf life seen within the population for more detailed molecular analysis. To investigate the effects of the presence of the QTL on metabolite content. To link metabolite content with shelf life. To investigate gene expression patterns during senescence to identify genes controlled by the selected QTL. Current work: The DH population is being screened with 60 SSRs (short sequence of nucleotides, typically 2 to 5, that are repeated in tandem), know to be polymorphic between the parents of the cross, using PCR. The products of which are multiplexed using the sequencer facilities. The trace data from the sequencer is inputted into Genemarker software to look for polymorphisms between the parental lines for each marker. Peak height data and genotype data matrices are created from gene marker to be used in Joinmap to create a linkage map based on LOD ratios. Using phenotypic data and information from the linkage maps QTL analysis is performed to locate QTLs for the trait bud yellowing. Future work: Analysis of key metabolites such as vitamin C, anthocyanins, glucoraphanin and glucobrassicin using high liquid performance chromatography (HPLC). Gene expression studies during senescence using microarrays. Potential to identify genes involved in senescence by comparison with the model plant system Arabidopsis Field trials in 2007 and 2008 to record phenotypic data to improve QTL definition for traits such as yellowing, head weight, diameter and circumference. A linkage map of B. oleracea var italica based on the MAR34xGD33 DH population with potential QTLs mapped relating to bud yellowing. AC-CACG13 AA-CATG40 20 AA-CATM5 24 AC-CAAM427 Na12_H0936 LG 2 BY3 L CHR3, b CHR3 H CC3, C CHR3, H CC4, a CC4, AC-CACM8 AC-CTCM6 AC-CTAM5 0 AC-CTAM10 2 AC-CACM9 12 AC-CTCM3 22 AC-CAGM2 23 AC-CATG225 AC-CACM2 27 AA-CATM635 LG 1 BY1 H CC4, a CHR3 H CHR3 BY2 a CC4 AC-CTAM6 0 AC-CTAM1 8 AC-CATG612 Ol10_D08 17 AC-CAGG4 35 AC-CAGM4 36 BN83B146 AA-CTAM7 51 AC-CTAG7 52 AC-CTAG3 54 AC-CACG7 63 AA-CTAM2 90 LG 4 BY6 L CC3, L CHR3 b CC3, b CHR3 H CC3, H CC4, C CC3, C CHR3 a CC4, BY5 a CC3 BY4 a CC4 BY7 C CC4 AC-CATM30 AC-CAGG314 AC-CAAG318 AC-CAAG421 AC-CATM522 AC-CTAM12AA-CATG12 AA-CTAM8 23 AA-CATG1824 Na12_C0829 AC-CATG432 LG 5 Ol12_G040 AC-CACM68 AC-CACM7 10 LG 7 AA-CTAG40 Na12_G128 AA-CATG839 AA-CTAG248 AA-CTAM550 AA-CTAM666 LG 8 AC-CTAM110 MB43 AC-CATG55 AC-CAGG28 LG6 BY8 L CHR3, b CC3, b CHR3 H CC3, H CC4, C CHR3, a CC4 AA-CATM70 AC-CTAG104 AC-CTCG212 AA-CTAG5 15 AC-CTCG118 AC-CTCM1 21 LG 9 BY9 L CHR4 Days to yellowing of GD33, MAR34, the F1 and 59 DH lines as assessed using the R.H.S colour charts. The values are means of 6 heads per line per replicate per year. Days to yellowing of the GD33 x MAR34 lines. X GD33 Mar34 Mar34 x GD33 F1 used to generate a doubled haploid mapping population GD33 Mar34 F1