José Antonio Garzón-Tiznado

Technological and Nutritional Properties of Flours and Tortillas from Nixtamalized and Extruded Quality Protein Maize (Zea mays L.)

ABSTRACT Nixtamalized and extruded flours from quality protein maize (QPM, V-537C) and tortillas made from them were evaluated for some technological and nutritional properties and compared with the commercial brand MASECA. Both QPM flours showed higher (P < 0.05) protein content, total color difference, pH, available lysine, and lower (P < 0.05) total starch content, Hunter L value, water absorption index, gelatinization enthalpy, resistant starch, and retrograded resistant starch than nixtamalized MASECA flour. Tortillas from nixtamalized and extruded QPM flours had higher contents of essential amino acids than tortillas from MASECA flour, except for leucine. Tortillas from processed QPM flours also showed higher (P < 0.05) values of the nutritional indicators calculated protein efficiency ratio (C-PER 1.80–1.85 vs. 1.04), apparent and true in vivo protein digestibility (78.4-79.1 vs. 75.6% and 76.4–77.4 vs. 74.2%, respectively), PER (2.30–2.43 vs. 1.31), net protein retention (NPR; 2.88–2.89 vs. 2.11),...

Microsatellite-based genetic diversity among accessions of maize landraces from Sinaloa in México.

In the state of Sinaloa México, traditional farmers still cultivate maize accessions with a wide diversity of morphological characteristics, but the gene reservoir maintained in these populations has been poorly studied and it is being lost due to changes in land use and the adoption of hybrid commercial varieties. The aim of this study was to evaluate the genetic diversity of some of these maize populations to contribute to their preservation. Twenty eight accessions were used for the analysis. DNA was extracted from 396 individuals and probed with 20 microsatellites distributed across the maize genome. A total of 121 alleles were obtained (average of 6.1 alleles per locus) and a total genetic diversity of 0.72. The UPGMA-cluster analysis, model-based population structure and principal component analysis revealed three major groups, one formed mainly by accessions of races typical of the Northwestern lowlands (Chapalote, Dulcillo del Noroeste, Tabloncillo Perla, Blando de Sonora and Elotero de Sinaloa) and the other two with accessions mainly from Tabloncillo and Tuxpeño. The high number of alleles per locus and total genetic diversity found in this study demonstrate a broad genetic basis of the accessions of maize landraces from Sinaloa, representing a gene reservoir useful in breeding programs.

Technological properties, antioxidant activity and total phenolic and flavonoid content of pigmented chickpea (Cicer arietinum L.) cultivars

Chickpeas are rich sources of highly nutritious protein and dietary fibre; the health benefits of consuming legumes such as antioxidant activity (AoxA) could be effective for the expansion of their food uses. The technological properties and antioxidant potential of five pigmented chickpea cultivars were evaluated. Protein content of the grains varied from 24.9 to 27.4 g/100 g sample (dw). The cooking time (CT) of the whole grains ranged from 90.5 to 218.5 min; the lowest CT corresponded to Black ICC3761 cultivar. The total phenolic content (TPC) and AoxA [oxygen radical absorbance capacity (ORAC) value] varied from 1.23 to 1.51 mg GAE/g sample (dw) and from 5011 to 5756 μmol TE/100 g sample (dw), respectively; Red ICC13124 showed the highest ORAC value. The differences in technological properties and AoxA among cultivars could be used in chickpea breeding programmes. Chickpea cultivars could contribute significantly to the management and/or prevention of degenerative diseases associated with free radical damage.

Transmission Efficiency of Tomato Apex Necrosis Virus by Bemisia tabaci (Hemiptera: Aleyrodidae) Biotype B in Tomato

ABSTRACT Tomato apex necrosis virus (ToANV) is a new virus that causes important damage in tomato crops from the Culiacan Valley, Sinaloa, Mexico. To understand the relationship between ToANV and its vector Bemisia tabaci (Hemiptera: Aleyrodidae) (Gennadius) biotype B, laboratory and greenhouse trials were completed to: 1) determine the acquisition and inoculation access periods of To ANV by B. tabaci from tomato to tomato, 2) understand the transmission efficiency at different B. tabaci population densities, 3) estimate the time from inoculation of the virus at different B. tabaci densities to manifestation of symptoms in the plants, and 4) determine the retention time of the virus by the insect vector. The presence of the virus in plants was determined by reverse transcription-polymerase chain reaction amplification of a 795-bp fragment (GenBank JN704068), which is phylogenetically related to ToANV (GenBank EF063242). The results showed that B. tabaci is an effective vector for ToANV with relatively long acquisition (12 h) and inoculation (9 h) access periods; a single adult is capable of transmitting and retaining the virus for up to 7 d, suggesting a persistent mode of transmission. These results will help in the development of management strategies for controlling the vector and the disease.

Occurrence of Fusarium oxysporum causing wilt on pepper in Mexico

Abstract A new disease on greenhouse pepper (Capsicum annuum L.) plants in Culiacan, Mexico with symptoms of chlorosis, wilting and vascular necrosis was observed in 2014. Sixty diseased pepper plants were collected from three different areas of the Culiacan Valley to determine the causal agent of the disease and analyse the potential risk presented by this disease in this region. Fusarium oxysporum was recovered consistently (88% of samples collected) and identified based on cultural, morphological and pathogenicity tests, as well as by PCR amplification and DNA sequencing of the TEF-1α gene. Two pathogenicity tests with 10 monoconidial isolates of F. oxysporum, which were selected randomly from diseased tissues, produced disease symptoms similar to those observed on pepper plants in the greenhouses. Symptoms were different from the typical root rot, wilting and necrosis caused by F. solani and F. oxysporum f. sp. radicis-capsici and instead matched those reported for F. oxysporum f. sp. capsici causing pepper wilt. The results suggest that the causal agent of pepper wilt in the samples analysed was F. oxysporum. This is the first report of pepper wilt caused by this fungus in Mexico, and this disease is a potential threat for pepper production in this region.

Heritability of the resistance to pepper huasteco yellow vein virus in wild genotypes of Capsicum annuum

Pepper huasteco yellow vein virus (PHYVV) is the main virus of pepper crop in Mexico. No resistant cultivars are available and resistance breeding is hampered by the lack of knowledge of heritability (h2) of PHYVV resistance. This is a continuation of previous studies and the objectives were to analyze the h2 and the behavior of the resistant trait to PHYVV. Four resistant assays were done with three resistant wild lines (UAS12, UAS13 and UAS10) of Capsicum annuum in the S4, S5, S6 and S7 generation under greenhouse conditions. Plants from all tests were inoculated with PHYVV through Bemisia tabaci. Line UAS12 was the most resistant showing a significantly proportion of resistant plants, less disease symptoms and longer incubation time, followed by the lines UAS13 and UAS10 in all assays. Distribution of symptoms showed a bimodal tendency in all the trials, suggesting that two groups of genes are involved in this resistance trait. The lines UAS12, UAS13 and UAS10 showed the same pattern of response to selection with an average of h2 of 0.17, 0.06, 0.02 and 0.00 in the S4, S5, S6 and S7, respectively. These results indicate that all lines responded positively to the selection in the S4, S5 and S6, whereas in the S7 there was no response by the possible exhaustion of variation. Line UAS12 is the most promising genotype and the lines UAS13 and UAS10 are genetic resources that can be supplemented to breed the resistance of PHYVV. These results provides basic information for resistance breeding.