What is heterosis PDF?

Table of Contents

Heterosis refers to the phenomenon that progeny of diverse varieties of a species or crosses between species exhibit greater biomass, speed of development, and fertility than both parents. Various models have been posited to explain heterosis, including dominance, overdominance, and pseudo-overdominance.

What is heterosis in plant breeding PDF?

The degree of heterosis is calculated as the difference in the phenotypic performance of a trait between a hybrid and the average of its two distinct parents. Naturally cross-pollinating species such as maize or rye typically display a much higher degree of heterosis than self-pollinating plants like wheat and barley.

What is heterosis and its types?

Heterosis may be defined as the superiority of an F1, hybrid over both its parents in terms of yield or some other character. Heterosis, or hybrid vigour, describes the superior performance of heterozygous hybrid individuals compared with their homozygous parental inbred lines… Heterosis – Its Types and Theories.

What are two basic theories of heterosis?

There are two main theories of heterosis and inbreeding depression. 1. Dominant hypothesis 2. Over dominance hypothesis.

What is the function of heterosis?

Heterosis, hybrid vigor, or outbreeding enhancement is the improved or increased function of any biological quality in a hybrid offspring. An offspring is heterotic if its traits are enhanced as a result of mixing the genetic contributions of its parents.

What are heterosis in plants and plant breeding?

heterosis, also called hybrid vigour, the increase in such characteristics as size, growth rate, fertility, and yield of a hybrid organism over those of its parents. Plant and animal breeders exploit heterosis by mating two different pure-bred lines that have certain desirable traits.

Who discovered heterosis?

Corn (maize) Corn heterosis was famously demonstrated in the early 20th century by George H. Shull and Edward M. East after hybrid corn was invented by Dr. William James Beal of Michigan State University based on work begun in 1879 at the urging of Charles Darwin.

What is another name for heterosis?

heterosis, also called hybrid vigour, the increase in such characteristics as size, growth rate, fertility, and yield of a hybrid organism over those of its parents.

What is the role of heterosis?

In plants, heterosis helps in increasing the yield of the crops by producing better quality and higher resistance to pests and diseases. It is accomplished by crossing different heterotic groups to produce a vigorous F1 hybrid progeny.

What are the advantages of heterosis?

Advantages of maternal heterosis are seen in maternal ability, reproduction, longevity, calf survivability, pounds of calf weaned and younger age at puberty. Paternal heterosis is similar to maternal heterosis in that it is the genetic advantage provided by the sire; benefits are also seen as increased bull fertility.

What are the different models of heterosis?

Various models have been posited to explain heterosis, including dominance, overdominance, and pseudo-overdominance.

What is the best book on heterosis?

Heterosis: Feeding people and protecting natural resources. In Genetics and Exploitation of Heterosis in Crops, J.G. omy and Crop Science Society of America), pp. 19–29. East, E.M. (1936). Heterosis. Genetics 21: 375–397. Eshed, Y., and Zamir, D. (1995).

What is meant by heterosis?

How much heterosis is high parent heterosis?

As much as 100 % or greater mid-parent heterosis (=F1 – MP, where MP is the mean of the parents) and over 40 % high-parent heterosis (=F1 – HP, where HP is the higher parent value) have been frequently observed in experimental plots [2–5]. It has been estimated that hybrids can outyield conventional cultivars by 30–40 % in production fields [6].