Development and initial evaluation of diversity array technology for soybean and mungbean

Diversity Array Technology (DArT), a technique for quickly generating large numbers of molecular markers, was established for two legume crops, soybean (Glycine max) and mungbean (Vigna radiata). For each crop, two genomic complexity reduction methods, utilizing PstI/TaqI and PstI/BstNI restriction digests, were selected for DNA clonal library development and for the isolation in each case of 7,680 DArT clones from genomic representations of pooled DNA samples. While the PstI/BstNI method produced more polymorphic clones than PstI/TaqI for the soybean library, there was no significant difference between the two methods for the mungbean library. Polymorphism frequencies in mungbean were around twice those in soybean, reflecting greater diversity in the mungbean samples. Even so, there were still nearly 1,500 unique polymorphic clones identified for soybean. The DArT marker transferability from soybean to mungbean (13.6%) was nearly five times higher than that from mungbean to soybean (3.1%). The percentage of DArT marker transferability between mungbean and several other Vigna species ranged from 3.4 to 20.2%. The genetic similarities among 11 diverse Vigna spp. samples, evaluated using the DArT mungbean library, were consistent with published information on these taxa. The results indicated that for soybean and mungbean, the DArT technique is an effective tool for marker generation in terms of speed and the numbers of markers identified. The transferability of markers between soybean and mungbean indicated that DArT may be useful for comparative genomic studies, while the ability of the mungbean library to discriminate between related Vigna taxa suggested that DArT may also be useful for studies of genetic diversity

Challenges of formulation and quality of biofertilizers for successful inoculation

The interest in biofertilizers is increasing and so is the potential for their use in sustainable agriculture. However, many of the products that are currently available worldwide are often of very poor quality, resulting in the loss of confidence from farmers. The formulation of an inoculant is a crucial multistep process that should result in one or several strains of microorganisms included in a suitable carrier, providing a safe environment to protect them from the often harsh conditions during storage and ensuring survival and establishment after introduction into soils. One of the key issues in formulation development and production is the quality control of the products, at each stage of the process. This review presents the different components and the major steps involved in the formulation of good quality biofertilizers, including the techniques used to assess the quality of the products following production. The quality of currently available inoculants is also reviewed, emphasizing the need for better quality control systems worldwide. (Résumé d'auteur