Seed coat permeability and its inheritance in a forage lupin (Lupinus hispanicus)
SummaryThe species Lupinus hispanicus, throught its use as self-seeding forage, can contribute to solve the problem of forage scarcity during the summer in the livestock farming of the central-west Iberian Peninsula. A feature of the highest importance in achieving self-seeding is the seed-coat permeability. An evaluation of this characteristic has been carried out in a Lupinus hispanicus collection from Salamanca (Spain), its inheritance, and the influence of daily temperature fluctuations on the ‘softening’ of the seeds. All the lines but one had impermeable seeds. It was established that the permeability of the seeds is controlled by the genotype of the mother-plant and the inheritance of this characteristic follows a simple Mendelian model, the permeability being recessive. It was also observed that seeds subjected to daily temperature fluctuations had an increased level of permeability.
Development of a PCR marker tightly linked to mollis, the gene that controls seed dormancy in Lupinus angustifolius L.
Wild plants of Lupinus angustifolius avoid extinction in a drought year by production of seeds with coats that are impermeable to water, preventing germination of a large percentage of the seed in any given year. Domesticated cultivars of this species carry the recessive gene mollis, making the seed coat permeable to water and, in turn promoting good crop establishment in the year of sowing. A dominant microsatellite-anchored fragment length polymorphism candidate marker was identified as being tightly linked to mollis in a population of recombinant inbred lines derived from domesticated and wild-type parents. The candidate marker was excised from the gel, amplified by PCR, sequenced and extended beyond the SSR end of the original MseI-SSR fragment. Two single nucleotide polymorphisms were found within this extended sequence. Specific primers were designed to create a marker 209 bp long. PCR products of these primers run on a single strand conformation polymorphism gel resolved in a co-dominant fashion. This marker will be used in marker-assisted selection for mollis when introgressing wild material into lupin breeding programmes.
Avian infectious bronchitis.
Avian infectious bronchitis (IB) is caused by the gammacoronavirus infectious bronchitis virus (IBV). The virus causes infections mainly in chickens and is a significant pathogen of commercial meat and egg type birds. IB is an acute, contagious disease characterised primarily by respiratory signs in growing chickens. In hens, decreased egg production and quality are often observed. Some strains of the virus are nephropathogenic and produce interstitial nephritis and mortality. The severity of IBV-induced respiratory disease is enhanced by the presence of other pathogens, including bacteria, leading to chronic complicated airsacculitis. Diagnosis of IB requires virus isolation or demonstration of viral nucleic acid from diseased flocks. Demonstration of a rising serum antibody response may also be useful. The widespread use of live and inactivated vaccines may complicate both the interpretation of virus isolation and serology findings. The occurrence of antigenic variant strains may overcome immunity induced by vaccination.