Sensitivity of two garden pea genotypes to physical and chemical mutagens

A study on the sensitivity of two breeding lines of garden pea to mutagenic agents was carried out in the Maritsa Vegetable Crops Research Institute, Plovdiv. The purpose was to evaluate the sensitivity of the Pisum sativum L. genotypes to physical and chemical mutagens. In the experiment, the pea seeds were irradiated single or combined with 60Co gamma rays (40, 80, 100, 200 and 400 Gy) and Ethyl methanesulfonate (EMS) at concentrations of 0.1 and 0.2 %. Visible morphological changes of the stems and leaves were observed in plant of M1 generation, such as shorter stems, double petiole, clover-shaped leaves and a couple of tendrils. Single treatments with 100 Gy 60Co induced the highest mutation frequency M.F. = 7.69 for line 88-7, and М.F. = 2.11 for line 97-3, reported in M2 generation. Higher doses or combined gamma rays and EMS treatments induced more efficiently mutations. Line 88-7 was selected for further mutagenic treatment due to the higher sensitivity assessed

PESTS ON ANNUAL LEGUME CROPS AND POSSIBILITIES FOR CONTROL IN BIOLOGICAL PRODUCTION

Biological production of legume crops is becoming more widespread in many countries, with research aimed at increasing yields and improving product quality. Legumes are an important element of agrotechnical approaches in biological systems. They are a suitable precursor for a various vegetable crops and are actively involved in crop rotation. Annual legumes are attacked by many pests, which at high densities can compromise the yield. Experiments to determine the effectiveness of biological plant protection products to control the main pests on beans and peas grown in a certified organic field were conducted at the Maritsa Vegetable Crops Research Institute, Plovdiv during the period 2019-2020. The tested pests were: black bean aphid (Aphis fabae Scop.), pea aphid (Acyrthosiphon pisum Harris), bean weevil (Acanthoscelides obtectus Say), pea weevil (Bruchus pisi L.), pea moths (Laspeyresia nigricana Step. and Laspeyresia dorsana L.) and twospotted spider mite (Tetranychus urticae Koch.). Tested products are: Piretro Natura EC 75 ml/da (a. i. pyrethrins), Neem Azal T/C 0.3% (a.i. azadirachtin), Naturalis 100 ml/da (a. i. Beauveria bassiana), Dipel 2 X 100 g/da (a. i. Bacillus thuringiensis var. kurstaki strain ABTS) and Rapax 100 ml/da (a. i. Bacillus thuringiensis subsp. kurstaki, strain EG 2348)

Population Response of Rhizosphere Microbiota of Garden Pea Genotypes to Inoculation with Arbuscular Mycorrhizal Fungi

This study of a legume’s rhizosphere in tripartite symbiosis focused on the relationships between the symbionts and less on the overall rhizosphere microbiome. We used an experimental model with different garden pea genotypes inoculated with AM fungi (Rhizophagus irregularis and with a mix of AM species) to study their influence on the population levels of main trophic groups of soil microorganisms as well as their structure and functional relationships in the rhizosphere microbial community. The experiments were carried out at two phenological cycles of the plants. Analyzes were performed according to classical methods: microbial population density defined as CUF/g a.d.s. and root colonization rate with AMF (%). We found a proven dominant effect of AMF on the densities of micromycetes and actinomycetes in the direction of reduction, suggesting antagonism, and on ammonifying, phosphate-solubilizing and free-living diazotrophic Azotobacter bacteria in the direction of stimulation, an indicator of mutualistic relationships. We determined that the genotype was decisive for the formation of populations of bacteria immobilizing mineral NH4+-N and bacteria Rhizobium. We reported significant two-way relationships between trophic groups related associated with soil nitrogen and phosphorus ions availability. The preserved proportions between trophic groups in the microbial communities were indicative of structural and functional stability

Organic Production of Snap Bean in Bulgaria: Pests and Diseases Incidence and Control, Soil Fertility and Yield

Among factors affecting snap bean production in organic growing systems, pests and diseases are of paramount importance. The current study was aimed to determine the impact of organic production practices on snap bean pests and diseases infestation, soil fertility and yield. Five treatments of plants during the whole growing season with a Bordeaux mixture at a dose of 3000 g/ha, provided more than 50 percent protective effect against the development of the bacterial blight Xanthomonas axanopodis pv. phaseoli and anthracnose Colletotrichum lindemuthianum. In organic fields, commercial bioproducts containing pyrethrins or entomopathogenic fungi Beauveria bassiana can be successfully applied to control the black bean aphid (Aphis fabae Scop.). To limit the attack of bean weevil (Acanthoscelides obtectus Say), phytopesticide containing pyrethrins can also be used. Against the two-spotted spider mite (Tetranychus urticae Koch.), products containing the active ingredient azadirachtin were seen to be effective five days after treatment. Soil amendment with vermicompost at a dose of 2850 L/ha slightly increased the amounts of water-soluble nutrients; however, soil remained nutrient deficient across the growing season. Among the tested Bulgarian varieties, Evros possessed higher yield, and appear to be suitable for organic system than the Tangra variety