Syllabus Dot Point 2.10 The Blueprint of Life
“Process information from secondary sources to describe an example of hybridization within a species and explain the purpose of this hybridization”
Read the article below, print it out and answer the questions provided
Mendel's model provided scientists with an understanding that could be used to improve agricultural crops. Plant breeders recognised that characters could, without being changed, be brought into new combinations in hybrid organisms. They carried out systematic crosses between different varieties of one species to form hybrids that had new combinations of desirable characters The crossing of different varieties of one species to produce new varieties with different combinations of characteristics is one kind of hybridisation. Another kind of hybridisation involves the crossing of different but closely related species. The aim of both kinds of hybridisation is to create new and better combinations of characters.
In general hybrid plants are more vigorous and higher yielding compared with their true breeding parents. The outcome of hybridisation is not always an improvement. It is also important to note that when hybrid offspring are produced artificially, they are designed to be cultivated or reared under controlled conditions of intensive agriculture, horticulture or farming and may not be suited to conditions in the wild.
In the late 1800s, the flour produced from Australian-grown wheats was too poor to be used for baking bread for human consumption. At that time, flour for baking bread was imported into
Australia, principally from Canada. The first wheats to be grown in Australia were old English varieties that ripened too late to survive the hot summers, produced poor flour and were affected by many fungal diseases.
In the late nineteenth and the early twentieth centuries, William Farrer (18451906) pioneered
Australian wheat research. He systematically used cross-breeding (hybridisation) to improve bread wheat (Triticum aestivum). Like Mendel with his edible peas, Farrer prevented self-fertilisation and carried out artificial crosses of wheat varieties. Farrer mainly used varieties of bread wheat (Triticum aestivum) in his experimental crosses, but he also used another closely related species, pasta wheat
(T. turgidum).
Farrer began his hybridisation work in 1886 on his small farm named 'Lambrigg' at Queanbeyan,
New South Wales. He succeeded in breeding many new wheat varieties, including varieties with features such as narrow leaves to reduce water loss that were suited to the drier climatic conditions in Australia. Other characteristics that Farrer introduced into his wheat varieties included:
• earlier ripening to suit the shorter growing season in the Australian wheat growing areas; early ripening is recessive to late ripening
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• improved baking quality improved yield (grains per head) resistance to the fungal disease known as bunt.

Farrer failed to breed a wheat variety that was resistant to another fungal disease, known as rust.
This was because he did not have access to a wheat variety with this characteristic, such as a rustresistant variety of Italian wheat that he could use as one of his parental plants. However, rust disease, which thrives in moist conditions, became less of a problem because Farrer produced wheat varieties that could grow in drier conditions and so were less prone to rust.
In one experiment, Farrer crossed an early-ripening Indian wheat variety (`Etauch') with a Canadian variety (`Fife') that had good baking properties. From the hybrid wheats produced, Farrer selected one that he called `Yandilla'. To improve its grain yield. Farrer then crossed `Yandilla' with a higher yielding variety known as `Purple Straw'. The result was a new variety that Farrer called `Federation' when it was released for commercial use in 1901. `Federation' combined the features of early ripening and high yield and, because it had a strong short straw, it was ideal for harvesting by a mechanical stripper. By 1910, 'Federation' was the most widely grown Australian wheat and remained so for about another 15 years.
The scientific wheat hybridisation work begun by Farrer continues today at such places as the Plant
Breeding Research Institute of the University of Sydney at Narrabri in New South Wales. This and wheat research institutes in other states continue to develop new wheat varieties that are high yielding, disease resistant and differ in maturity times.
Questions
1.
Define the term hybridisation within a species and give an example
2.
Outline the history of wheat hybridisation and improvement to wheat in Australia
3.
Give the genus and species name of the wheat variety Farrer used for within species hybridisation.
4.
Using a table compare and contrast the qualities of early strains of wheat to the hybrid varieties that we use today.