Effects of Genetically Removing Lectin Seed Protein on Horticultural and Seed Characteristics of Common Bean

Abstract

Abstract The absence of seed lectin in common bean (Phaseolus vulgaris L.) was shown to be inherited as a single recessive gene and allelic to genes conditioning 6 different lectin types. In inbred backcross lines, the allele from ‘Sanilac’ (a navy class bean) for the presence of lectin was semidominant to the lectinless allele from ‘U.I. 1140’ (a Great Northern class bean) for quantity of lectin. Backcross lines with lectin (L/L) and without lectin (1/1) were developed using 2 lectinless donor parents (‘U.I. 1140’ and ‘U.I. 111', a Pinto class bean) and ‘Sanilac’ as the recurrent parent. Backcross lines and parents were grown in the field and analyzed for days to flower, seed yield, seed weight, percentage protein, and quantities of lectin and phaseolin. There were significant differences between lectin genotypes (L/L vs. 1/1) for all traits except yield, seed weight, and nonphaseolin nonlectin protein. Backcross lines without lectin had substantially higher levels of phaseolin and slightly more total protein than lines with lectin. The data suggested that phaseolin over-compensated for the absence of lectin in 1/1 backcross lines. The implications of these findings toward the nutritional improvement of bean protein are discussed.