Multi-Population Selective Genotyping to Identify Soybean (Glycine max (L.) Merr.) Seed Protein and Oil QTLs

Plant breeders continually generate ever-higher yielding cultivars, but also want to improve seed constituent value, which is mainly protein and oil in soybean [Glycine max (L.) Merr.]. Identification of genetic loci governing those two traits would facilitate that effort. Though genome-wide association offers one such approach, selective genotyping of multiple bi-parental populations offers a complementary alternative, and was evaluated here, using 48 F_2:3 populations (n = ca. 224 plants) created by mating 48 high protein germplasm accessions to cultivars of similar maturity, but with normal seed protein content. All F_2:3 progeny were phenotyped for seed protein and oil, but only 22 high and 22 low extreme progeny in each F_2:3 phenotypic distribution were genotyped with a 1536-SNP chip (ca. 450 bi-morphic SNPs detected per mating). A significant QTL on one or more chromosomes was detected for protein in 35 (73%) and for oil in 25 (52%) of the 48 matings, and these QTLs exhibited additive effects of ≥ 4 g kg^-1 and R² values of 0.07 or more. These results demonstrated that a multiple-population selective genotyping strategy, when focused on matings between parental phenotype extremes, can be successfully used to identify germplasm accessions possessing large-effect QTL alleles. Such accessions would be of interest to breeders to serve as parental donors of those alleles in cultivar development programs, though 17 of the 48 accessions were not unique in terms of SNP genotype, indicating that diversity amongst high protein accessions in the germplasm collection is less than what might ordinarily be assumed.

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A Genetic Map between Gossypium hirsutum and the Brazilian Endemic G. mustelinum and its Application to QTL Mapping

Among the seven tetraploid cotton species, little is known about transmission genetics and genome organization in Gossypium mustelinum, the species most distant from the source of most cultivated cotton, G. hirsutum. In this research, an F₂ population was developed from an interspecific cross between G. hirsutum and G. mustelinum (HM). A genetic linkage map was constructed mainly using simple sequence repeat (SSRs) and restriction fragment length polymorphism (RFLP) DNA markers. The arrangements of most genetic loci along the HM chromosomes were identical to those of other tetraploid cotton species. However, both major and minor structural rearrangements were also observed, for which we propose a parsimony-based model for structural divergence of tetraploid cottons from common ancestors. Sequences of mapped markers were used for alignment with the 26 scaffolds of the G. hirsutum draft genome, and showed high consistency. Quantitative trait locus (QTL) mapping of fiber elongation in advanced backcross populations derived from the same parents demonstrated the value of the HM map. The HM map will serve as a valuable resource for QTL mapping and introgression of G. mustelinum alleles into G. hirsutum, and help clarify evolutionary relationships between the tetraploid cotton genomes.

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Management of portal vein thrombosis in cirrhosis: More shadows than lights

I believe that the report on hemostatic balance in cirrhosis, recently published in Digestive and Liver Disease, adds important considerations about the topic. However, the assumption that portal vein thrombosis (PVT) in cirrhosis should be an indication to anticoagulant (AC) treatment is not obvious and should merit further debate [1]. In fact, whether PVT affects the outcome of cirrhosis still remains an open issue. In particular, although PVT in cirrhosis is associated with a bad prognosis, it is not evident whether this reflects that PVT more easily arises in the context of severe liver failure or, on the other hand, whether PVT really worsens hepatic function by reducing portal flow in a context of already reduced hepatic functional reserve, so negatively affecting survival.

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Management of portal vein thrombosis in cirrhosis: More shadows than lights

I believe that the report on hemostatic balance in cirrhosis, recently published in Digestive and Liver Disease, adds important considerations about the topic. However, the assumption that portal vein thrombosis (PVT) in cirrhosis should be an indication to anticoagulant (AC) treatment is not obvious and should merit further debate [1]. In fact, whether PVT affects the outcome of cirrhosis still remains an open issue. In particular, although PVT in cirrhosis is associated with a bad prognosis, it is not evident whether this reflects that PVT more easily arises in the context of severe liver failure or, on the other hand, whether PVT really worsens hepatic function by reducing portal flow in a context of already reduced hepatic functional reserve, so negatively affecting survival.

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