Content of zinc, iron and their absorption inhibitors in Nicaraguan common beans (Phaseolus vulgaris L.).

Common bean (Phaseolus vulgaris L.), the staple crop of Nicaragua, provides protein and nonhaem iron, but inhibitors such as phytate may prevent absorption of iron and zinc by the consumer. Warehouses in Nicaragua do not have controlled atmospheres, so beans are exposed to high temperatures and humidities that may accelerate quality loss. To evaluate the impact of 6months of storage on quality, four national accessions of common bean were submitted to two treatments, a conventional warehouse with uncontrolled temperature and humidity, and accelerated ageing at 40°C and 75% RH. Iron content was 61-81mg/kg of which 3-4% was bioavailable, and zinc content was 21-25mg/kg, of which 10-12% was bioavailable. Bioavailability generally increased in storage, significantly so in year-old INTA Linea 628 in accelerated ageing. The concentration of phytate was 8.6-9.6mg/g and it contained 54-63% of the total phosphorus. Improvement in bioavailability of divalent cations is needed.

A rapid antibody-based test for Sec-2, a marker for the short arm of chromosome 2 of rye (2RS).

A simple monoclonal antibody-based screening test has been developed for the presence of translocations of the short arm of chromosome 2 of rye (2RS) with wheat chromosome 2B. 2RS encodes a set of about three polypeptides known as Mr 75 000 gamma-secalins. Use of the antibody test for these secalins enabled screening of several hundred seeds per day. The antibody could readily distinguish 2BL-2RS translocations and 2R substitutions from 1BL-1RS translocations or nontranslocation wheats. Use of the antibody in analysis of segregating progeny for Sec-2 in several wheat backgrounds was successful. Results with a selection of the seed population were checked using protein gel electrophoresis, with 100% correct confirmation. Key words : rye, wheat, seed proteins, translocation, diagnostic test.