Worldwide,broccoli(Brassica oleracea var.italica)is among the most economically important,nutritionally rich,and widely-grown vegetable crops.To explore the genomic basis of the dramatic changes in broccoli morphology...Worldwide,broccoli(Brassica oleracea var.italica)is among the most economically important,nutritionally rich,and widely-grown vegetable crops.To explore the genomic basis of the dramatic changes in broccoli morphology in the last century,we evaluated 109 broccoli or broccoli/cauliflower intermediates for 24 horticultural traits.Genotype-bysequencing markers were used to determine four subpopulations within italica:Calabrese broccoli landraces and hybrids,sprouting broccoli,and violet cauliflower,and to evaluate between and within group relatedness and diversity.While overall horticultural quality and harvest index of improved hybrid broccoli germplasm has increased by year of cultivar release,this improvement has been accompanied by a considerable reduction in allelic diversity when compared to the larger pool of germplasm.Two landraces are the most likely founding source of modern broccoli hybrids,and within these modern hybrids,we identified 13 reduction-in-diversity genomic regions,53 selective sweeps,and 30(>1 Mbp)runs of homozygosity.Landrace accessions collected in southern Italy contained 4.8-fold greater unique alleles per accessions compared to modern hybrids and provide a valuable resource in subsequent improvement efforts.This work broadens the understanding of broccoli germplasm,informs conservation efforts,and enables breeding for complex quality traits and regionally adapted cultivars.展开更多
The abundance of predatory phytoseiid mites,Typhlodromus pyri,important biological control agents of spider mite pests in numerous crops,is positively influenced by the density of leaf trichomes and tuft-form domatia ...The abundance of predatory phytoseiid mites,Typhlodromus pyri,important biological control agents of spider mite pests in numerous crops,is positively influenced by the density of leaf trichomes and tuft-form domatia in vein axils.Identification of the genetic regions controlling both trophic levels could facilitate the improvement of predatory mite habitat in breeding programs.The abundance of T.pyri and non-glandular trichomes was measured in a segregating F1 family derived from the cross of the complex Vitis hybrid,‘Horizon’,with Illinois 547-1(V.rupestris B38×V.cinerea B9),finding positive correlation among traits.High density genetic maps were used to localize one major quantitative trait locus(QTL)on chromosome 1 of Illinois 547-1 associated with both predatory mite abundance and leaf trichomes.This QTL explained 23%of the variation in phytoseiid abundance and similar amounts of variance in domatia rating(21%),domatia size(16%),leaf bristle density(37%in veins and 33%in blades),and leaf hair density(20%in veins and 15%in blades).Another nine QTL distributed among chromosomes 1,2,5,8,and 15 were associated solely with trichome density,and explained 7–17%of the phenotypic variation.Combined,our results provide evidence of the genetic architecture of non-glandular trichomes in Vitis,with a major locus influencing trichome densities,domatia size and predatory mite abundance.This information is relevant for breeding grapevines with a more favorable habitat for biological control agents.展开更多
The influence of humic substances (HS) formulations derived from sedimentary and compost sources was studied on plant growth at cell level and chlorophyll retention during accelerated senescence of leaf tissue. The di...The influence of humic substances (HS) formulations derived from sedimentary and compost sources was studied on plant growth at cell level and chlorophyll retention during accelerated senescence of leaf tissue. The direct effect of HS formulations was studied on cell expansion using cucumber and radish cotyledon expansion test. The cucumber hypocotyl elongation test was used to study the effect on cell elongation. Chlorophyll pigment retention in excised leaf tissue incubated in dark with high temperature was assessed to study the effect on leaf senescence. Explant tissues were incubated directly in the solutions of the formulations at the concentration recommended for foliar application to the crop plants. HS formulations showed significant variations in their direct bio-stimulatory effects. Formulations derived from compost sources were found superior in terms of inducing a direct stimulatory effect on cell expansion and cell elongation and in maintaining chlorophyll pigment retention during accelerated senescence. HS from sedimentary sources stimulated cell expansion and delayed chlorophyll degradation to a lesser extent compared to HS from compost. However, HS formulations derived from sedimentary sources used in this study were not effective in inducing cell elongation in the cucumber hypocotyl elongation test. The direct bio-stimulatory effect of HS formulations differed significantly between the formulations that were evaluated.展开更多
Acidity is a critical component determining apple fruit quality.Previous studies reported two major acidity quantitative trait loci(QTLs)on linkage groups(LGs)16(Ma)and 8(Ma3),respectively,and their homozygous genotyp...Acidity is a critical component determining apple fruit quality.Previous studies reported two major acidity quantitative trait loci(QTLs)on linkage groups(LGs)16(Ma)and 8(Ma3),respectively,and their homozygous genotypes mama and ma3ma3 usually confer low titratable acidity(TA)(<3.0 mg ml^(−1))to apple fruit.However,apples of genotypes Ma-(MaMa and Mama)or Ma3-(Ma3Ma3 and Ma3ma3)frequently show an acidity range spanning both regular(TA 3.0–10.0 mg ml^(−1))and high(TA>10mgml^(−1))acidity levels.To date,the genetic control for high-acidity apples remains essentially unknown.In order to map QTLs associated with high acidity,two genomic DNA pools,one for high acidity and the other for regular acidity,were created in an interspecific F1 population Royal Gala(Malus domestica)×PI 613988(M.sieversii)of 191 fruit-bearing progenies.By Illumina paired-end sequencing of the high and regular acidity pools,1,261,640 single-nucleotide variants(SNVs)commonly present in both pools were detected.Using allele frequency directional difference and density(AFDDD)mapping approach,one region on chromosome 4 and another on chromosome 6 were identified to be putatively associated with high acidity,and were named Ma6 and Ma4,respectively.Trait association analysis of DNA markers independently developed from the Ma6 and Ma4 regions confirmed the mapping of Ma6 and Ma4.In the background of MaMa,20.6%of acidity variation could be explained by Ma6,28.5%by Ma4,and 50.7%by the combination of both.The effects of Ma6 and Ma4 in the background of Mama were also significant,but lower.These findings provide important genetic insight into high acidity in apple.展开更多
基金supported by Specialty Crop Research Initiative grant no.2016-51181-25402 from the USDA National Institute of Food and Agriculture.
文摘Worldwide,broccoli(Brassica oleracea var.italica)is among the most economically important,nutritionally rich,and widely-grown vegetable crops.To explore the genomic basis of the dramatic changes in broccoli morphology in the last century,we evaluated 109 broccoli or broccoli/cauliflower intermediates for 24 horticultural traits.Genotype-bysequencing markers were used to determine four subpopulations within italica:Calabrese broccoli landraces and hybrids,sprouting broccoli,and violet cauliflower,and to evaluate between and within group relatedness and diversity.While overall horticultural quality and harvest index of improved hybrid broccoli germplasm has increased by year of cultivar release,this improvement has been accompanied by a considerable reduction in allelic diversity when compared to the larger pool of germplasm.Two landraces are the most likely founding source of modern broccoli hybrids,and within these modern hybrids,we identified 13 reduction-in-diversity genomic regions,53 selective sweeps,and 30(>1 Mbp)runs of homozygosity.Landrace accessions collected in southern Italy contained 4.8-fold greater unique alleles per accessions compared to modern hybrids and provide a valuable resource in subsequent improvement efforts.This work broadens the understanding of broccoli germplasm,informs conservation efforts,and enables breeding for complex quality traits and regionally adapted cultivars.
基金supported by the Specialty Crop Research Initiative of the National Institute of Food and Agriculture,U.S.Department of Agriculture,under award number 2011-51181-30635 and National Research Initiative award number 2004-35302-14725.
文摘The abundance of predatory phytoseiid mites,Typhlodromus pyri,important biological control agents of spider mite pests in numerous crops,is positively influenced by the density of leaf trichomes and tuft-form domatia in vein axils.Identification of the genetic regions controlling both trophic levels could facilitate the improvement of predatory mite habitat in breeding programs.The abundance of T.pyri and non-glandular trichomes was measured in a segregating F1 family derived from the cross of the complex Vitis hybrid,‘Horizon’,with Illinois 547-1(V.rupestris B38×V.cinerea B9),finding positive correlation among traits.High density genetic maps were used to localize one major quantitative trait locus(QTL)on chromosome 1 of Illinois 547-1 associated with both predatory mite abundance and leaf trichomes.This QTL explained 23%of the variation in phytoseiid abundance and similar amounts of variance in domatia rating(21%),domatia size(16%),leaf bristle density(37%in veins and 33%in blades),and leaf hair density(20%in veins and 15%in blades).Another nine QTL distributed among chromosomes 1,2,5,8,and 15 were associated solely with trichome density,and explained 7–17%of the phenotypic variation.Combined,our results provide evidence of the genetic architecture of non-glandular trichomes in Vitis,with a major locus influencing trichome densities,domatia size and predatory mite abundance.This information is relevant for breeding grapevines with a more favorable habitat for biological control agents.
文摘The influence of humic substances (HS) formulations derived from sedimentary and compost sources was studied on plant growth at cell level and chlorophyll retention during accelerated senescence of leaf tissue. The direct effect of HS formulations was studied on cell expansion using cucumber and radish cotyledon expansion test. The cucumber hypocotyl elongation test was used to study the effect on cell elongation. Chlorophyll pigment retention in excised leaf tissue incubated in dark with high temperature was assessed to study the effect on leaf senescence. Explant tissues were incubated directly in the solutions of the formulations at the concentration recommended for foliar application to the crop plants. HS formulations showed significant variations in their direct bio-stimulatory effects. Formulations derived from compost sources were found superior in terms of inducing a direct stimulatory effect on cell expansion and cell elongation and in maintaining chlorophyll pigment retention during accelerated senescence. HS from sedimentary sources stimulated cell expansion and delayed chlorophyll degradation to a lesser extent compared to HS from compost. However, HS formulations derived from sedimentary sources used in this study were not effective in inducing cell elongation in the cucumber hypocotyl elongation test. The direct bio-stimulatory effect of HS formulations differed significantly between the formulations that were evaluated.
基金supported in part by the Agriculture and Food Research Initiative competitive grant no.2014-67013-21660,National Institute of Food and Agriculture,US Department of Agriculture(NIFA,USDA).
文摘Acidity is a critical component determining apple fruit quality.Previous studies reported two major acidity quantitative trait loci(QTLs)on linkage groups(LGs)16(Ma)and 8(Ma3),respectively,and their homozygous genotypes mama and ma3ma3 usually confer low titratable acidity(TA)(<3.0 mg ml^(−1))to apple fruit.However,apples of genotypes Ma-(MaMa and Mama)or Ma3-(Ma3Ma3 and Ma3ma3)frequently show an acidity range spanning both regular(TA 3.0–10.0 mg ml^(−1))and high(TA>10mgml^(−1))acidity levels.To date,the genetic control for high-acidity apples remains essentially unknown.In order to map QTLs associated with high acidity,two genomic DNA pools,one for high acidity and the other for regular acidity,were created in an interspecific F1 population Royal Gala(Malus domestica)×PI 613988(M.sieversii)of 191 fruit-bearing progenies.By Illumina paired-end sequencing of the high and regular acidity pools,1,261,640 single-nucleotide variants(SNVs)commonly present in both pools were detected.Using allele frequency directional difference and density(AFDDD)mapping approach,one region on chromosome 4 and another on chromosome 6 were identified to be putatively associated with high acidity,and were named Ma6 and Ma4,respectively.Trait association analysis of DNA markers independently developed from the Ma6 and Ma4 regions confirmed the mapping of Ma6 and Ma4.In the background of MaMa,20.6%of acidity variation could be explained by Ma6,28.5%by Ma4,and 50.7%by the combination of both.The effects of Ma6 and Ma4 in the background of Mama were also significant,but lower.These findings provide important genetic insight into high acidity in apple.
