Seed-setting in potatoes as affected by spraying with a-naphthaleneacetamide and by light
SummarySpraying potato plants with dilute concentrations of a-naphthal-eneacetamide was not effective in increasing flower or seed ball production in the greenhouse at Beltsville Maryland, or Greeley, Colorado. Higher concentrations reduced flower production at Presque Isle, Maine.Sebago and Irish Cobbler produced more seed balls at Greeley than at Beltsville. Less cloudy weather at Greeley during the winter months is probably the chief factor responsible for this result.S 245–25, when self-pollinated, produced as many seed balls at Beltsville as at Greeley. It appears that this variety flowers and sets seed more readily under fairly unfavorable light conditions than either Sebago or Irish Cobbler.
Genetic and Environmental Factors Contributing to Reproductive Success and Failure in Potato
The foundation of potato (Solanum tuberosum) breeding and the development of new potato varieties is the crossing of parents to produce seeds that contain new combinations of alleles that may be superior to those in either parent. In this review, we begin by highlighting a signature problem of potato breeding, the widespread lack of fertility observed in many lines. We summarize normal development of male and female reproductive structures, fertilization and embryo growth. Various manifestations of male and female sterility are then described. These include defects of meiosis and mitosis, bud abscission, competition between reproductive structures and tubers for resources, and cytoplasmic male sterility. Effects of environmental determinants, such as temperature and light intensity, on fertility are discussed. Finally, suggested best practices that promote fertility are provided as a guide for those conducting breeding and genetics work with potato.
Mathematical Time and Physical Time in the Theory Of Relativity
In the Theory of Relativity time is an imaginary quantity that can not be observed; it is a multiplication of a number that indicates duration of material change and number i that is an imaginary number. i on the square is -1. Time i⁄t is a mathematical time that describes the speed and the duration of material change. In the Universe one can observe physical time only as a stream of material change. It is not that change run in physical time, change itself is physical time.. Distinction between imaginary mathematical time and visible physical time opens some new perspectives into interpretation of Theory of Relativity. c