Topic Object and importance of the science of General plant breeding and seed production

Topic 1.
Object and importance of the science of General plant breeding and seed production

Lecture prospects:
1.The science, short history.
2.Objectives and the main issues,, achievements.
3.Its future and significance.
4.The scheme of breeding process and the schemes of production of elite and high reproduction seeds.



Plant breeding is a method of altering the genetic pattern of plants to increase their value and utility for human welfare. It is a purposeful manipulation of plants to create desired plant types that are better suited for cultivation, give better yield and are disease resistant.

Plant breeding is done for the following objectives :
Increase the crop yield
Improve the quality of the crop
Increase tolerance to environmental conditions like salinity. extreme temperatures and drought
Develop a resistance to pathogens
Increase tolerance to the insect pest

History of plant breeding
HISTORY OF PLANT BREEDING In broad sense history of plant breeding can be divided into Four parts
1. Pre Mendelian era:- before 1900.
2. Mendelian era:- 1900 to 1920.
3. Post Mendelian era:- 1921 to 1950.

4. Modern era:- after 1950.

1694: Camerarius of Germany first to demonstrate sex in plants and suggested crossing as a method to obtain new plant types.
1665: Robert Hooke(England): First described the cell and known as father of cell biology. 
700 B.C.: Babylonians and Assyrians hand pollinate date palm artificially.  1000 B.C.: Domestication of all important food crops in the New World completed.  3000 B.C.: Domestication of all important food crops in the Old World completed.  9000 B.C.: First evidence of plant domestication in the hills above the Tigris River. 
1. PRE MENDELIAN ERA:- The process of bringing a wild species under human management is referred to as Domestication.

MENDELIAN ERA:-
1914: Shull, G.H: First used the term heterosis for hybrid vigour. 1910: Bruce, A.B. keable, F. and Pellew, C. Elaborated the dominance hypothesis of heterosis proposed by davenport.  1909: Nilsson-Ehle: Given the explanation of multiple factor hypothesis for Grain colour of Wheat by using a Pedigree breeding and Bulk breeding.  1909: Shull conducted extensive research to develop inbreds to produce hybrids use of F1 hybrids between inbreds in corn breeding.  1908: Shull, G.H (US) East, E.M (US) proposed over dominance hypothesis independently working with maize.

POST MENDELIAN ERA:-
1940: Jenkins, M.T: Described the procedure of recurrent selection. 1939: Goulden, C.H: First suggested the use of single seed descent method for advancing segregating generations of self pollinating crops.  1936: East, E.M: Supported over dominance hypothesis of heterosis proposed by East and Shull in 1908.  1935: Nagahern proposed the origin of tetraploid species of Brassica using a triangle.  1935: Vavilov published the scientific basis of plant breeding.  1934: Dustin discovered colchicines.  1933: Rhoades: Discovered cytoplasmic male sterility in Maize.
1950: McClintock discovered the Ac-Ds system of transposable elements. 1950: Hughes and Babcock: First discovered sporophytic system of self incompatibility in Crepis foetida.  1945: Hull, F.H: Coined the terms recurrent selection and overdominance working with maize.  1944: Avery, MacLeod, and McCarty: Described the transforming principle and suggested that DNA, not protein, is the hereditary material.