摘要
Most crops were first domesticated about 13 000 to 11 000 years ago. Humans are dependent on crops for survival, and from the beginnings of agriculture have been energetically involved in developing crops that better serve their needs （Allard 1999）. During the last decades breeding has contributed approximately a 50% contribution to increasing the world＇s food crop production. However, plant breeding only began to adopt a scientific approach in the 1900s, when Mendel＇s hybridization experiment was rediscovered. Mendelian genetics and the development of the statistical concepts of randomJzatJon and replication had considerable impact on plant breeding methods （Hallauer et al. 1988）. In spite of the fact that scientific crop breeding has only existed for one century, it is a discipline that is developing very quickly. The major objective of crop breeding programs is to develop new genotypes that are genetically superior to those currently available for specific environments. To achieve this objective, breeders employ a range of selection methods and technologies （Hallauer et al. 1988; Falconer and Mackay 1996; Allard 1999）.
Most crops were first domesticated about 13 000 to 11 000 years ago. Humans are dependent on crops for survival, and from the beginnings of agriculture have been energetically involved in developing crops that better serve their needs （Allard 1999）. During the last decades breeding has contributed approximately a 50% contribution to increasing the world＇s food crop production. However, plant breeding only began to adopt a scientific approach in the 1900s, when Mendel＇s hybridization experiment was rediscovered. Mendelian genetics and the development of the statistical concepts of randomJzatJon and replication had considerable impact on plant breeding methods （Hallauer et al. 1988）. In spite of the fact that scientific crop breeding has only existed for one century, it is a discipline that is developing very quickly. The major objective of crop breeding programs is to develop new genotypes that are genetically superior to those currently available for specific environments. To achieve this objective, breeders employ a range of selection methods and technologies （Hallauer et al. 1988; Falconer and Mackay 1996; Allard 1999）.
