That no generally applicable law of the formulation and development of hybrids has yet been successfully formulated can hardly astonish anyone who is acquainted with the extent of the task.
1564 - 1616
1803 – 1882
1854 – 1900
1942 – 2016
1928 – 2014
1835 – 1910
1869 – 1948
1884 – 1962
1898 – 1963
1929 – 1993
1879 – 1955
1809 – 1865