CHARACTERIZATION OF THE EFFECT OF INTROGRESSED SEGMENTS OF CHROMOSOME-7 AND CHROMOSOME-10 FROM LYCOPERSION CHMIELEWSKII ON TOMATO SOLUBLE SOLIDS, PH, AND YIELD

Three chromosomal segments from the wild tomato L. chmielewskii have b een introgressed into the L. esculentum genome. Using molecular marker s they have been mapped to the middle and terminal regions of chromoso me 7 (7M,7T respectively), and to the terminal region of chromosome 10 (10T). This study was conducted to further clarify the physiological influence of the introgressed segments of chromosome 7 and 10 on tomat o soluble solids (SS), and other fruit and yield parameters. The effec t of the 10T segment was evaluated using five lines that differ for th e presence of this segment. As previously reported this segment increa sed fruit pH with no significant effect on SS. Sixty-four BC2F5 backcr oss inbred lines (BILs) were developed from a cross using LA1501 (an L . esculentum line that contains the 7M and 7T fragments from L. chmiel ewskii) as the donor parent, and VF145B-7879 (a processing cultivar) a s the recurrent parent. BILs were classified in four groups (+ +, inbr eds without either of the L. chmielewskii segments; 7M +, lines with o nly the 7M segment; + 7T, inbreds with only the 7T segment, and 7M7T, inbreds with both segments) based on RFLP information, and then compar ed to each other for all the parameters under study. Inbreds homoyzgou s for the 7M fragment displayed greater SS (26%) and higher pH (0.10) than the control group (+ +). The 7L fragment did not influence either SS or pH, but was observed to significantly increase fruit yield by 1 2% when compared to the recurrent parent. A gene or genes that increas e yield without affecting SS or pH may have potential in the developme nt of commerical cultivars.