Resistance to<i><scp>B</scp>emisia tabaci</i>biotype B of<i><scp>S</scp>olanum pimpinellifolium</i>is associated with higher densities of type IV glandular trichomes and acylsugar accumulation

Abstract

Abstract Advances in tomato breeding for pest resistance have been achieved via gene introgression from wild S olanum (section L ycopersicon ) species ( S olanaceae). Ninety‐nine F 3 families derived from an interspecific cross using as parental lines S olanum lycopersicum L . ‘ LAM ‐148' (susceptible standard) and S olanum pimpinellifolium L . ‘ TO ‐937‐15’ (multiple pest resistance accession with type IV glandular trichomes and acylsugar accumulation) were evaluated for their resistance against the whitefly B emisia tabaci ( G ennadius) ( H emiptera: A leyrodidae) biotype B in free‐choice and no‐choice tests for oviposition and adult colonization. The parental lines and eight F 3 families with contrasting levels of resistance against the whitefly were selected and investigated in additional assays, which included the estimation of trichome densities and foliar acylsugar levels. The F 3 families BTR ‐302 and BTR ‐331 exhibited low amounts of eggs of whitefly and transgressive segregation for type IV glandular trichome density with values greater than that of TO ‐937‐15 plants. However, the tested families did not surpass the total foliar acylsugar content found in TO ‐937‐15. BTR ‐331 exhibited low colonization in the free‐choice test and it was the least preferred F 3 family in the no‐choice test. The higher resistance levels of BTR ‐331 were associated with a positive combination of higher type IV trichome density and higher acylsugar levels. Some F 3 families displayed reduced fruit set due to the presence of flowers with style exertion of the antheridial‐cone. Fruit weight at harvest stage of the selected families (from 4.9 to 14.5 g) was lower than that of LAM ‐148 (139.5 g) but higher than that of TO ‐937‐15 plants (1.3 g). Therefore, although difficult to reach due to the simultaneous segregation of many polygenic traits, the combination of high B . tabaci resistance levels with superior horticultural traits is feasible. These results confirm TO ‐937‐15 as a source of biotype B resistance. From the breeding standpoint, the genetic similarity between S . lycopersicum and S . pimpinellifolium would allow a more efficient resistance introgression by facilitating recombination and minimizing the potentially undesirable linkage drag associated with this trait.