Diversity of genus Passiflora L. in Mexico and a particular study on Passiflora biflora Lam. fruit characteristics

Genetic Resources and Crop Evolution - In Mexico there is a high diversity of species of the genus Passiflora. Present work resumes the number of Passiflora species listed for Mexico in herbariums...     

Anti-plasmodial activity of the extracts and two sesquiterpenes from Cyperus articulatus

Two sesquiterpenes, corymbolone and mustakone, isolated from the chloroform extract of the rhizomes of Cyperus articulatus, exhibited significant anti-plasmodial properties. Mustakone was approximately ten times more active than corymbolone against the sensitive strains of the Plasmodium falciparum.     

Antagonistic potential of Trichoderma spp. against Rhizoctonia solani and use of M13 microsatellite-primed PCR to evaluate the antagonist genetic variation

Journal of Plant Diseases and Protection - Rhizoctonia solani is the most important pathogen involved in cotton seedling disease in Egypt. Variations in the antagonistic activity of 20 isolates...     

Screening and selection of lentil (Lens Miller) germplasm resistant to seed bruchids (Bruchus spp.)

Seed weevil (Bruchus spp.) is one of the most damaging pests to lentil crop, and the current chemical treatments to control this insect present numerous disadvantages. In this work, we have searched for resistant or almost resistant lentil cultivars to be used as potential sources of genes for resistance to bruchids as a more sustainable and environmentally friendly approach to diminish harvest loss. Thus, a lentil germplasm collection of 571 accessions from 27 different countries, and including wild species was screened for susceptibility to seed bruchids under natural field conditions in Central Spain. Infestation was evaluated in comparison with a check (lentil cultivar ??Lyda??) according to the number of eggs per pod and the infestation rate in seeds (IR). A large variation of IR (0?C70?%) was observed among accessions although, in general, wild species were consistently less affected by bruchids than the check. A total of 32 accessions, including Lens culinaris Medikus subsp. culinaris, Lens culinaris Medikus subsp. orientalis (Boiss.) Ponert, Lens nigricans (M. Bieb.) Godr., and Lens lamottei Cezfr., showed lower infestation rates than the check and were selected as potential sources of resistance to this pest. Potential mechanisms of resistance of selected accessions and their inclusion in a breeding program are outlined.     

Wheat straw and cellulolytic fungi application increases nodulation, nodule efficiency and growth of fenugreek (Trigonella foenum-graceum L.) grown in saline soil

This study was performed to evaluate the ability of cellulolytic fungi and wheat straw incorporation to improve the nodulation, growth and nitrogen status of fenugreek grown in saline soils. NaCl addition to the growth medium at rates of 0.5 and 1% strongly decreased the enzymatic activity of the ten tested moulds. Three of these fungi, Aspergillus niger, Chaetomium globosum and Trichoderma harzianum, showed the highest enzymatic activity. The three moulds have the ability to degrade straw in the presence of NaCl and T. harzianum was the best straw degrader. Inoculating the plants with Rhizobium meliloti strain TAL1373 and cellulolytic fungi slightly promoted nodulation, growth and nitrogen accumulation when plants were grown with the addition of 0.5% NaCl when compared to plants inoculated with R. meliloti alone. However, application of wheat straw with cellulolytic fungi significantly enhanced growth, nodulation and nodule efficiency at 0.5 and 1.0% salinity. The greatest values of nodulation and growth parameters were obtained with a straw-Trichoderma harzianum combination. Cellulolytic fungi and wheat straw increased the concentration of Ca, Mg and K in the shoots and roots of plants. The increase in dry matter production and N content was mainly due to improved N₂ fixation reflected by enhanced formation and growth of nodules as well as nitrogenase activity. Received: 20 January 1997     

Risk factors associated with reproductive performance in small-scale dairy farms in Mexico

Several studies suggest that reproductive performance in small-scale dairy farms is low reducing the farms’ profitability. Therefore, identifying risk factors associated with low reproductive performance is a key step to implement an improved reproductive management program. Accordingly, the aim of the present study was to identify the main risk factors affecting the reproductive performance of cows in small-scale dairy farms. Ninety-six dairy farms were incorporated into this study, and data from 1263 lactations were collected with different events as potential risk factors. Logistic regression models were used to assess the association (odds ratio, OR) and impact (population attributable fraction, PAF) between the potential risk factors and the reproductive variables. The main risk factors associated with assisted calving were male calf and primiparous cows (OR?=?1.7, PAF?=?0.315 and OR?=?1.5, PAF?=?0.131, respectively), while for retained fetal membranes (RFM) were assisted calving and abortion (OR?=?4.5, PAF?=?0.440 and OR?=?8.1, PAF?=?0.239, respectively). The main risk factors for days to first service over 70 days in milk were low body condition score at calving (BCS?≤?2.5) and primiparous cows (OR?=?2.2, PAF?=?0.285 and OR?=?1.4; PAF?=?0.096, respectively), while for days open over 110 days in milk were low BCS at calving (BCS?≤?2.5) and primiparous cows (OR?=?1.7, PAF?=?0.213 and OR?=?1.4; PAF?=?0.096, respectively) The main risk factor for non-pregnant cows at first service was RFM (OR?=?1.7; PAF?=?0.059). In conclusion, assisted calving, male calf, BCS?≤?2.5 and RFM were the main risk factors associated with reduced reproductive performance in small-scale dairy farms in tropical and subtropical regions of Mexico.