Proceedings of the XLVI Italian Society of Agricultural Genetics - SIGA Annual Congress

Giardini Naxos, Italy - 18/21 September, 2002

ISBN 88-900622-3-1

Poster Abstract - 4.28

Use of wild QTLs for the improvement of tomato fruit quality

Termolino P., Grandillo S.

National Research Council- Research Institute for Vegetable and Ornamental Plant Breeding (CNR – IMOF), Via Università 133, 80055 Portici (NA)

tomato, exotic germplasm, QTLs, quality, MAS

Most traits of agronomic interest, including those related to quality, are polygenically inherited. Exotic germplasm represents a valuable and unique source of genetic variation, but it has rarely been used for the genetic improvement of quantitative traits. By means of molecular markers, NILs carrying favourable wild QTL alleles have been developed from diverse interspecific crosses in tomato.

We selected two NILs, TA523 and IL1-4, containing wild inrogressions for the bottom of chromosome 1 derived from L. hirsutum (acc. LA1777) and L. pennellii (acc. LA716), respectively. Both lines are known to carry QTLs that can improve soluble solids content of the fruit. For fruit color we selected three lines, TA517, TA1160 and IL4-4 containing wild introgressions for the bottom of chromosome 4 derived from L. hirsutum (acc. LA1777), L. peruvianum (acc. LA1708) and L. pennellii (acc. LA716), respectively.

With the purpose of improving the gene pool of elite processing tomato lines adapted to the pedo-climatic conditions of Southern Italy, we tested the 5 NILs in hybrid combination with three processing tomato tester lines (T137, T143 and T145). Each line was also crossed to the corrispondent control parent: cv. E6203 for the QTL-NILs TA523, TA517 and TA1160 and cv. M82 for the two ILs, IL1-4 and IL4-4. The five NILs, the correspondent hybrid combinations, along with the two control cultivars and the three testers, were evaluated in a replicated field trial conducted during the summer 2001 in Sarno (Naples). Ten agronomic traits were measured including yield, fruit weight, fruit shape, external and internal fruit color and soluble solids content.

For the two chromosome 1 lines tested, the results indicate that IL1-4 does not exert positive effects on any of the 10 traits analized. On the other hand, a significant (P<0.05) 11% increase in soluble solids content was reported for TA523 in hybrid combination with the tester line T143.

Of the three chromosome 4 lines tested, TA517 showed the most interesting results. More specifically, for the hybrid T145 x TA517, significant (P<0.05) increases of 22% for external color and of 28% for internal color were observed. Interestingly, for this hybrid combination no major negative effects were reported for the other traits analized. Also, for the line IL4-4 significant (P<0.05) increases of 16-20% for the external color and of 19-22% for the internal color were observed in hybrid combination with T143 and T145, respectively. This line, however, exhibited negative effects of other traits including plant weight and fruit shape. No significant positive effects were observed for the QTL-NIL TA1160 and the derived hybrid combinations.

The feasibility of using MAS to break undesirable linkages will be discussed.