Foliar leptine production in segregating F₁, Inter-F₁, and backcross families ofSolanum chacoense bitter

Abstract

Levels of foliar leptine glycoalkaloids were measured in segregating F₁, inter-F₁, and backcross families derived fromS. chacoense (PI 320287) sibs 55-1 and 55-3, which axe (respectively) high and nil leptine producers, and from crosses of these two genotypes with 8380-1, which produces high levels of leptine, to study the inheritance of leptine biosynthesis inS. chacoense. A total of five F₁ families was produced from reciprocal crosses between 55-3 and 55-1 and between 8380-1 and 55-3, and from the cross 8380-1 x 55-1. The F₁ crosses produced two leptine classes, high (≥62% of total glycoalkaloids; TGA) and low (≤17% of TGA). Twenty-three families were derived from F₁ intercrosses and backcrosses of high x high, low x low, high x low, and low x high F₁ individnals. These families produced all high, all low, or both high and low leptine classes, depending upon type of cross. Three of the reciprocal (high x low) F₁ families segregated 1:1 for high:low leptine, and progeny from the (high x high) 8380-1 x 55-1 cross were all high, consistent with control by a single recessive gene in this population. One of the reciprocal families (9501) differed slightly but significantly (p=0.05) from 1:1. All of the low x high and high x high inter-F₁ and backcross families segregated as expected based on a single recessive gene model; however, five of eight high x low and four of six low x low families differed significantly from expectation, suggesting the presence of additional factors affecting the inheritance and expression of leptine glycoalkaloids in this population orS. chacoense.