Inheritance of Stringless Pod in Pisum sativum L.

Abstract

In crosses between stringless and stringy podded pea cultivars, all plants of the F 1 and backcross to the stringy parent had stringy pods. F 2 ratios varied widely among crosses, and populations always had more stringy plants than expected, based on a single locus. The ratio of nonsegregating (stringy): segregating F 3 families derived from stringy F 2 plants fit a single-gene hypothesis in half of the crosses. Backcrosses of F 1 to the stringless parent fit the expected 1:1 ratio when the pollen parent was stringless, but the reciprocal backcrosses showed a deficiency of stringless plants, suggesting that poor competitive ability of pollen bearing the stringless factor was the reason for deficiencies of stringless plants. It is concluded that stringlessness is controlled by a single recessive gene for which the designation sin-2 is proposed. A reduction in pod size, plant height, and number of wrinkled seed segregates was associated with stringlessness.