Natural Cross‐Pollination in Blue and Yellow Lupines 1

T O FACILITATE the planning of efficient breeding programs with lupines, one of the major cover crops in the Southeastern United States, experiments were initiated in the fall of 1950 to determine the amount of crosspollination in bitter blue lupine (Lupinus angusdifdius L.) and sweet yellow lupine (L. luteus L.) under nursery conditions at Gainesville, Fla. European workers3 had already reporkd that cross-pollination is always more frequent in yellow lupine than in blue lupine and that its extent varies according to the distance to the nearest apiary. Some characteristics of common bitter blue lupine are pink flowers, colored seed, and purple seedling pigmentation. A recessive gene is known to inhibit the production of pigment and produce strains of blue lupine with white seed coat, white flowers, and no seedling pigmentation. In the yellow lupine, the speckled seed coat characteristic is dominant to the white seed coat characteristic, which depends on one pair of recessive genes. These characteristics were used to classify all progeny in the cross-pollination studies.