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There is a very high prevalence of diabetes in India today which is increasing on a North to South axis. In addition to lifestyle changes, Indian people may be more susceptible to insulin resistance. Observational studies suggest that the consumption of diets with a low glycemic impact is associated with a reduced risk of diabetes. Maltitol is a bulk sweetener belonging to the polyols family and exhibiting a low glycemic response (GR). Genetic background has already been mentioned as an influent factor in modulating the GR of various foods. So, assessing glucose homeostasis including glycemic and insulinemic responses (IR) after maltitol consumption in Indians may be helpful in gaining a better understanding of this result from a physiological standpoint. The objective of this clinical study was to evaluate the GR and IR of maltitol in healthy Indian volunteers. The protocol followed Food and Agriculture Organization (FAO) recommendations. After an overnight fast, GR and IR of maltitol and reference (glucose) were measured on 12 subjects (50 g dissolved in 150 ml of mineral water). Glucose tolerance was assessed both before and after testing, the subjects being randomly allocated either to the maltitol or the glucose groups. Both glucose and insulin plasma concentrations were assessed in venous blood. Mean blood glucose levels were significantly lower after the consumption of maltitol compared with glucose from time points 15 to 90 min. GR of maltitol was found to be 20.4 ± 9.3 % of glucose GR. After maltitol consumption, the mean insulin blood levels were significantly lower from time points 15 to 120 min compared with the reference subjects. IR of maltitol was found to be 17.8 ± 9.9 % of glucose IR. We confirmed that the maltitol GR in healthy Indians is low. Moreover, maltitol displays a very low insulinemic response which may be of interest for diabetics in India.

The aim of the present study was to transfer resistance to P. capsici alleles at four quantitative trait loci (QTLs) from a small fruited pepper into a bell pepper recipient line using markers. The marker-assisted selection program was initiated from a doubled-haploid line issued from the mapping population and involved three cycles of marker-assisted backcross (MAB). Two populations, derived by selfing the plants selected after the first selection cycle, were genotyped and evaluated phenotypically for their resistance level. The additive and epistatic effects of the four resistance factors were re-detected and validated in these populations, indicating that introgression of 4 QTLs in this MAB program was successful. A decrease of the effect for the moderate-effect QTLs and of the epistatic interaction was observed. Phenotypic evaluations of horticultural traits were performed on sample of each backcross generation. The results indicated an efficient return to the recipient phenotype using this MAB strategy.

'Criollo de Morelos 334' (CM334) is one of the most promising sources of resistance to Phytophthora capsici in pepper. This Mexican accession is distantly related to bell pepper and its resistance displays a complex inheritance. The QTLs involved in resistance to P. capsici were previously mapped. In order to transfer the resistance factors from CM334 into a bell pepper genetic background, a modified, recurrent breeding scheme was initiated. The breeding population was divided into three sub-populations which were screened by distinct phenotypic tests of increasing severity. The plants from the first sub-population were screened with low-severity tests and backcrossed to the susceptible bell pepper; the plants from the second and third sub-populations were screened by more severe resistance tests and crossed with the plants from the first and second sub-populations, respectively. In this study, the phenotypic data for the three sub-populations during five screening/intermating cycles were analysed. In parallel, the changes in allelic frequencies at molecular markers linked to the resistance QTLs were reported. The resistance phenotype and allelic frequencies strongly depended on the sub-population and screening severity. Regarding allelic frequency changes across the selection cycles, a loss of resistant QTL alleles was observed in the first sub-population, particularly for the low-effect QTLs, whereas a better conservation of the resistant QTL alleles was observed in the two other sub-populations. The same trend was observed in the phenotypic data with an increasing resistance level from the first to the third sub-populations. The changes in the allelic frequencies of loci not linked to resistance QTLs and for horticultural traits across the breeding process indicated that the recovery of the recipient parent genome was not significantly affected by the selection for resistance.

Phytophthora capsici Leonian, known as the causal agent of the stem, collar and root rot, is one of the most serious problems limiting the pepper crop in many areas in the world. Genetic resistance to the parasite displays complex inheritance. Quantitative trait locus (QTL) analysis was performed in three intraspecific pepper populations, each involving an unrelated resistant accession. Resistance was evaluated by artificial inoculations of roots and stems, allowing the measurement of four components involved in different steps of the plant-pathogen interaction. The three genetic maps were aligned using common markers, which enabled the detection of QTLs involved in each resistance component and the comparison of resistance factors existing among the three resistant accessions. The major resistance factor was found to be common to the three populations. Another resistance factor was found conserved between two populations, the others being specific to a single cross. This comparison across intraspecific germplasm revealed a large variability for quantitative resistance loci to P. capsici. It also provided insights both into the allelic relationships between QTLs across pepper germplasm and for the comparative mapping of resistance factors across the Solanaceae.

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