Selection methods for seedling vigor in birdsfoot trefoil

In 1969, 72 large-seeded lines derived through open pollination were used to establish a seedling vigor test upon which three selection schemes were imposed. First, the best 16 lines were identified and their maternal parents intercrossed to form a selection-by-genotype group. Second, vigorous seedlings were selected out of every fourth line, brought to bloom and interpollinated to form a selection-by-phenotype group. Third, from each of the 16 best lines four vigorous seedlings were selected and later intercrossed to form a selection-by-geno-phenotype group. Using the seeds produced, progeny tests were established to evaluate the germplasm selected by the three methods. The genotype method was effective, straightforward, and reasonably reliable. The geno-phenotype method was more variable in results but potentially more rewarding. The phenotype method was the least desirable. The implications of these results in a program of recurrent selection for seedling vigor are discussed.