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Title: LEPTINES AND OTHER GLYCOALKALOIDS IN TETRAPOID SOLANUM TUBEROSUM X S. CHACOENSE F-2 HYBRID AND BACKCROSS FAMILIES

Author
item Sanford, Lind
item Kowalski, Stanley
item Ronning, Catherine
item Deahl, Kenneth

Submitted to: American Journal of Potato Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/8/1997
Publication Date: N/A
Citation: N/A

Interpretive Summary: The Colorado potato beetle is a major insect pest of potatoes in nearly all production areas of the United States. Controlling this pest with insecticides is expensive and can be environmentally damaging. Development of resistant potato varieties would help alleviate these problems. Chemicals called leptine glycoalkaloids, which deter feeding of the beetle, are found in the leaves of the wild potato species S. chacoense. The genes controlling the synthesis of foliar leptines were transferred from this species to the commercial potato species by hybridization. The hybrid plants were self pollinated and were also crossed with the commercial potato species. Nearly all plants from these crosses produced significant quantities of leptines in leaves but not in tubers. Many of these plants will be useful in breeding productive, beetle resistant potato varieties. Potato producers will benefit from using such varieties in reduced production costs, and consumers will benefit from lower food costs and lower environmental impacts of insecticides.

Technical Abstract: The leptine glycoalkaloids from Solanum chacoense Bitter are potential resistance factors to Colorado potato beetle, Leptinotarsa decemlineata Say. A selected sample of 17 F1 hybrids (4x) from crosses of a 4x S. chacoense clone that synthesizes leptines (8380-1) with 4x S. tuberosum L. lines were selfed to generate F2 hybrids (4x) and were also backcrossed to S. tuberosum. Glycoalkaloid (GA) content in foliage and tubers was measured for 786 sibling genotypes from the two generations in the field at Beltsville, Maryland. Leptines were found in the foliage of all F2 hybrids and in 98% of the backcross genotypes. Leptines were not detected in tubers from either generation. Foliage concentrations of leptines for the F2 hybrids averaged 156 mg/100g fresh weight (FW). The proportion of the total GA content consisting of leptines averaged 42%. By backcrossing the F1 hybrids to S. tuberosum, the average concentration of leptines was reduced to 44 mg/100g FW. The proportion of leptines averaged 16%. The tuber contents of solanine plus chaconine glycoalkaloids averaged 52 mg/100g FW for the F2 hybrids and 27 mg/100g for the backcross genotypes.