Ren Y.,Beijing Academy of Agriculture and Forestry Sciences |
Ren Y.,Key Laboratory of Urban Agriculture North |
Ren Y.,Beijing Key Laboratory of Vegetable Germplasm Improvement |
Ren Y.,Chinese Academy of Agricultural Sciences |
And 15 more authors.
Molecular Breeding | Year: 2015
Fusarium wilt (FW) caused by Fusarium oxysporum f. sp. niveum (FON) is the major soilborne disease of watermelon (Citrullus lanatus L.). The development and deployment of resistant cultivars is generally considered to be an effective approach to control FW. In this study, an F8 population consisting of 103 recombinant inbred lines derived from a cross between the cultivar 97103 and a wild accession PI 296341-FR was used for FON race 1 and race 2 fungal inoculations. One major QTL on chromosome 1 for FON race 1 resistance was detected with a logarithm of odds of 13.2 and explained phenotypic variation R2 = 48.1 %; two QTLs of FON race 2 resistance on chromosomes 9 and 10 were discovered based on the high-density integrated genetic map we constructed. The nearest molecular marker should be useful for marker-assisted selection of FON race 1 and race 2 resistance. One receptor kinase, one glucan endo-1,3-β-glucosidase precursors and three acidic chitinase located in the FON-1 QTL genomic region. In Qfon2.1 QTL region, one lipoxygenase gene, five receptor-like kinases and four glutathione S-transferase genes are discovered. One arginine biosynthesis bifunctional protein, two receptor kinase proteins and one lipid-transfer protein located in Qfon2.2 QTL region. Based on SNP analysis by using 20 re-sequenced accessions of watermelon and 231-plant F2 population generated from Black Diamond × Calhoun Grey, we developed a SNP marker Chr1SNP_502124 for FON-1 detection. © 2015, The Author(s).
Ji G.,China Agricultural University |
Ji G.,Beijing Academy of Agriculture and Forestry Sciences |
Ji G.,Beijing Key Laboratory of Vegetable Germplasm Improvement |
Zhang J.,Beijing Academy of Agriculture and Forestry Sciences |
And 15 more authors.
Scientia Horticulturae | Year: 2015
Inheritance of sex forms in watermelon (Citrullus lanatus) is not well described. In this study, we made five pairs of crosses of watermelon plants with different sex forms and grew progeny in two different seasons to investigate the inheritance of sex forms and the seasonal effect on sex expression. We showed that environmental factors have no effect on sex forms, but they affect sex expression on individual flowers as more pistillate flowers were observed in spring than in autumn. This suggests that short photoperiod and low temperatures promote formation of pistillate flowers in watermelon. In the F2 population of the cross of andromonoecious (SL3H or AKKZW)×monoecious (XHB), the segregation ratio is 9 monoecious: 3 trimonoecious: 4 andromonoecious, and the segregation ratio in BC1P1 (F1×andromonoecious parent) is 1 monoecious: 1 trimonoecious: 2 andromonoecious. The segregation ratio in the F2 population of the gynoecious (XHBGM)×monoecious (XHB) is 3 monoecious: 1 gynoecious whereas the segregation ratio in the BC1P1 (F1×gynoecious parent) is 1 monoecious: 1 gynoecious. The segregation ratio in the F2 population of gynoecious×andromonecious cross is 27 monoecious: 12 andromonoecious: 9 gynoecious: 9 trimonoecious: 4 hermaphroditic: 3 gynomonoecious. The segregation ratio in the BC1P1 population (F1×gynoecious) is 1 monoecious: 1 gynoecious whereas the segregation ratio in the BC1P2 (F1×andromonoecious) is 1 monoecious: 1 trimonoecious: 2 andromonoecious. Taken together, the results suggested that three recessive alleles, andromonoecious (a), gynoecious (gy) and trimonoecious (tm) control the sex forms in watermelon, and a allele is epistatic to the tm allele. The following phenotype-genotype relationships are proposed for each of the sex forms in watermelon: monoecious, A_Gy_Tm_; trimonoecious, A_Gy_tmtm; andromonoecious, aaGy_Tm_ or aaGy_tmtm; gynoecious, A_gygyTm_; gynomonoecious, A_gygytmtm; and hermaphroditic, aagygyTm_ or aagygytmtm. © 2015 Elsevier B.V..
Yu S.,Beijing Academy of Agriculture and Forestry Sciences |
Yu S.,Key Laboratory of Biology and Genetic Improvement of Horticultural Crops North China |
Yu S.,Beijing Key Laboratory of Vegetable Germplasm Improvement |
Su T.,Beijing Academy of Agriculture and Forestry Sciences |
And 20 more authors.
Molecular Breeding | Year: 2016
Specific-locus amplified fragment sequencing is a high-resolution method for genetic mapping, genotyping, and single nucleotide polymorphism (SNP) marker discovery. Previously, a major QTL for downy mildew resistance, BraDM, was mapped to linkage group A08 in a doubled-haploid population derived from Chinese cabbage lines 91–112 and T12–19. The aim of the present study was to improve the linkage map and identify the genetic factors involved in downy mildew resistance. We detected 53,692 high quality SLAFs, of which 7230 were polymorphic, and 3482 of the polymorphic markers were used in genetic map construction. The final map included 1064 bins on ten linkage groups and was 858.98 cM in length, with an average inter-locus distance of 0.81 cM. We identified six QTLs that are involved in downy mildew resistance. The four major QTLs, sBrDM8, yBrDM8, rBrDM8, and hBrDM8, for resistance at the seedling, young plant, rosette, and heading stages were mapped to A08, and are identical to BraDM. The two minor resistance QTLs, rBrDM6 (A06) and hBrDM4 (A04), were active at the rosette and heading stages. The major QTL sBrDM8 defined a physical interval of ~228 Kb on A08, and a serine/threonine kinase family gene, Bra016457, was identified as the possible candidate gene. We report here the first high-density bin map for Chinese cabbage, which will facilitate mapping QTLs for economically important traits and SNP marker development. Our results also expand knowledge of downy mildew resistance in Chinese cabbage and provide three SNP markers (A08-709, A08-028, and A08-018) that we showed to be effective when used in MAS to breed for downy mildew resistance in B. rapa. © 2016, Springer Science+Business Media Dordrecht.