Screening and identification of antagonistic <Emphasis Type="Italic">Streptomyces</Emphasis> spp. against <Emphasis Type="Italic">Clavibacter michiganensis</Emphasis> subsp. <Emphasis Type="Italic">michiganensis</Emphasis> from tomato rhizosphere

The objectives of our present study were to isolate antagonistic Streptomyces from tomato rhizosphere, and evaluate the potential strain for the biological control of bacterial canker of tomato. One hundred and seventy strains of isolated from tomato rhizosphere were tested for antibiosis activity against Clavibacter michiganensis subsp. michiganensis on double-layer agar. Sixty-three isolates showed antibiosis activity with diameter of an inhibition zone ranging from 1.0–6.5 cm. Fifteen Streptomyces strains had strong antibiosis activity against C. m. subsp. michiganensis with diameter of the inhibition zone above 4.0 cm on double-layer agar. Especially, the strain named Z-L-22 showed the strongest antibiosis activity with 6.5 cm inhibition zone. The fermentation filtrate also showed a high inhibition activity against Gram-positive bacteria such as Streptomyces scabies, Staphylococcus aureus, and Bacillus subtilis. Morphological, physiological and biochemical tests combined with 16S rDNA sequence analysis were carried out to identify the strain Z-L-22. Characteristics of the Z-L-22 were similar to those of Streptomyces setonii, and the 16S rDNA sequence showed 99.4% homology to S. setonii. Based on the polyphase taxonomic views, the Z-L-22 was identified as S. setonii.     

CPIDS: a plant parameter selection program for erosion prediction modeling

Newly developed erosion prediction models require detailed input parameters including those describing cropping systems. Each model exhibits a different level of complexity for crop growth modeling, and many plant parameters for these models are difficult to obtain. Furthermore, numerous parameters require interpretation from other measurable plant characteristics. We developed a database containing measurable plant characteristics to supply users of these new erosion prediction technologies with the necessary parameters. The new database supports the Revised Universal Soil Loss Equation (RUSLE) and the Water Erosion Prediction Project (WEPP) erosion prediction models. The Crop Parameter Intelligent Database System (CPIDS) was developed to assist crop database builders and users of RUSLE and WEPP in interpretation of plant characteristics and selection of plant parameters. CPIDS is a Microsoft® Windows™-based program, currently running on a personal computer (PC) under Windows 3.1™, Windows 95™ and Windows NT 4.0™.     

Characteristics of interspecific hybrids between <Emphasis Type="Italic">Pleurotus ostreatus</Emphasis> and <Emphasis Type="Italic">P. eryngii</Emphasis>

In this study, three species of oyster mushroom (Pleurotus osturatus, P. eryngii and P. cornucopia) were crossed together in order to aggregate benefit special attributes to the genotype (s). The monokaryon of each of these species was prepared. Then, the monokaryons of two species were placed at 5 mm distance from each other to produce dikaryon. The results showed that, from among 700 crosses, only the crosses of eryngii and osturatus monokaryons were grown toward each other and produced clamps (dikaryons). Four produced hybrids were noted H₁, H₃₂, H₁₁ and H₄₀. The spans of produced hybrids were prepared; then, they were grown into sterile media and attributions of hybrids were studied. The results indicated that H₁₁ hybrid was an appropriate hybrid in terms of the number of days until growing, number of days until the observation of the first pin and the days from planting to harvest. However, H₄₀ was the best hybrid based on cap diameter, dry and fresh weight of fruit body, yield and biomass. It is expected that these interspecific hybrids employ for future oyster mushroom breeding programs.     

Study of biochemical composition of seeds and green beans of vegetable cowpea (<Emphasis Type="Italic">Vigna Ung.</Emphasis> ssp. <Emphasis Type="Italic">Sesquipedalis</Emphasis>)

The article presents the results of investigation of the variability of biochemical parameters of seeds and green beans of vegetable cowpea accessions (Vigna unguiculata ssp. sesquipedalis (L.) Verdc.) introduced for use in breeding. Variations of biochemical parameters of seed quality and green beans (such as protein, fat, ash content, fiber, NFES) were established. New data on the fractional composition of proteins (albumins, globulins, prolamins, glutelins) from seeds and green beans were obtained. These data are of great importance for the evaluation of the starting material and the formation of a breeding program and the selection of rational strategies of individual selection from the source populations.     

Studies on isolated microspore embryoid induction of <Emphasis Type="Italic">C. annuum</Emphasis> L.

A system to improve isolated microspore embryoid induction rate of pepper (Capsicum annuum L.) was studied in this paper. The results showed that low-temperature pretreatment, growth regulators combinations, activated carbon concentrations, and preculture temperatures were critical factors affecting embryoid formation of isolated pepper microspores in vitro. One day after pretreatment of the buds at 4°C, the anthers that differentiated and developed into embryos were cultured in double-layer medium system for one week at 7°C and then went on culturing at 28°C in darkness. All the seven genotypes of the tested pepper responded to this protocol. The embryoid induction rate of the best genotype increased from 81.11% to 147.22%. This protocol can be used as a potential tool for producing doubled haploid plants for pepper breeding.