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.
Seed Physiology and Germination of Grain Legumes
An integrative review and analysis of seed germination of grain legumes, combining seed structural morphology, physiology of dormancy and germination metabolism is presented, bridging between disciplines and research approaches. A deeper understanding of the links between seed development, environmental conditions, and processes controlling seed germination and metabolism is attempted, in view of present and future needs for improved grain legume cultivars with greater range of adaptation to more extreme climatic and edaphic conditions.
The influence of the growing season and the following dry season on the hardseeedness of subterranean clover in different environments
The length of the growing period in the spring months appears to be a critical factor in the development of hardseededness in subterranean clover (Trifolium subterraneum L.). Environments with relatively long spring growing periods cause a higher proportion of hard seeds to form at field maturity, and increase the resistance which these hard seeds are capable of offering to the softening effects of the following summer environment. During the dry summer period the rate of softening of hard seeds is determined, not only by the previous growing season but also by the summer environment itself. Hot summer environments with wide soil surface temperature fluctuations are conducive to a relatively rapid rate of softening. Grazing or removal of the dry topgrowth from a pasture during the summer increases the daily soil surface temperature fluctuations, and results in the hard seeds softening at an increased rate. Differences in the overall environment manifest themselves in terms of site and seasonal variation in the proportion of hard seeds which survive beyond the opening of the following growing season. The scope for variation is wide, and this has agronomic significance from the aspect of long-term persistence of the species.