[OG bub]

Population-improvement methods fall naturally into two categories: those based on phenotypic selection without progeny testing and those based on phenotypic selection with progeny testing. Traditionally, the practice of early farmers and early corn breeders was to select numerous plants with particular ear, kernel, or other characters they believed to be favorable, and thereafter, generation after generation, they grew the next generation, or generations, from mixtures of seeds produced on selected plants of the previous generation. Such mass selection without progeny testing is the original and simplest breeding method, and, historically, it has been the most widely used method for breeding all seed-propagated crops, including both inbreeders and outbreeders. Selection based on visual evaluation, or on simple measurements of the phenotypic characteristics of seed parents of individual plants, is referred to as phenotypic mass selection. This type of mass selection was conceptually simple and easy to conduct; further, its single-generation breeding cycle was appealing. However, a major weakness of such mass selection, not fully appreciated until late in the nineteenth century, was that it did not allow satisfactory control of pollen parents in outcrossing species. Under open-pollination the successful pollen could come from any random plant in the population, including plants less desirable phenotypically than the selected seed parents. Another weakness, also not widely recognized until late in the nineteenth century, was that phenotypic mass selection depends for success on high heritability-that is, on high regression of offspring on parents. One of the late-nineteenth-century variants of phenotypic mass selection, practiced specifically in corn, was ear-to-row breeding in which ears from selected plants were planted in different rows and only those progeny rows that were judged visually to be -superior were harvested for further selection. This progeny-testing procedure was effective, but only for very highly heritable characters such as oil content. In practice, car-to-row selection turned out to be largely ineffective, or at best weakly effective, for characters, such as yield, that are considerably affected by environment. A further later refinement sometimes included in ear-to-row selection was the selection of not only female parents but also superior male parents from the same population. The selected male parents were then crossed with the selected female parents, with the expectation that the progeny obtained would be superior to progeny that resulted from outcrossing with random male plants in the population. However, the small additional gains sometimes realized rarely justified the added labor requirement for the improved control of parentage and/or the added time and labor required for progeny tests. Thus, ear-to-row breeding, even with embellishments, came to be recognized in the early 1900s as, at best, only a marginally effective method of population improvement. It was not until many years later that improved yield-testing techniques and improved ways of estimating heritabilities came into wide use.

great post bub, thanks alot for the info. keep your head up.

guerilla

[Buddle]

Cool..its nice to be from a farming family..There is a lot more thinking involved with farming than the avg Joe realizes.Throw herd health and their breeding into the mix and it really multiplies..

[Jamaica Nice]

Great info, thanks bub

[sith44]

Excellent info OP...thanks!