Over the past two and half decades there has been an explosion of progress in a growing number of model self incompatibility (SI) systems on our understanding of the molecular, biochemical and cellular processes underlying the recognition of self pollen and the initiation of a cascade of biochemical and cellular events that prevent self fertilization. These studies are unrevealing the complexity of a trait (SI) whose sole purpose, as far as we know, is to exert a strong influence on the breeding system of plants. Evolutionary interest in floral traits that influence the breeding system and in the forces that shape these traits began with Darwin who devoted one complete book to the subject (Darwin 1876) and significant portions of a second book. The evolution of plant breeding systems is often viewed as the interplay between the advantages and disadvantages of selfing. Evolutionary biologists have long noted that there are three primary advantages to selfing. First, there is an inherent genetic transmission advantage to selfing because a plant donates two haploid sets of chromosomes to each selfed seed and can still donate pollen to conspecifics. Second, selfing can provide reproductive assurance when pollinators are scarce or and third, it often costs less, in terms of energy and other resources, to produce selfed seed (e.g. fewer resources are expended to attract and reward pollinators. Some major questions remain unanswered concerning the evolution of stylar SRNases. Most pressing is the apparent disparity in patterns of diversification seen in the Solanaceae and Plantaginaceae relative to what is observed in the Rosaceae. Thus, we reviewing current publication regarding the evolutionary analysis basic RNases towards comprehensive view.
Part of the book: Plants for the Future