Thrips are damaging pests in pepper worldwide. They can cause damage directly by feeding on leaves, fruits or flowers, and also indirectly by transferring viruses, especially tomato spotted wilt virus (TSWV). Although thrips are among the most damaging pests in pepper, until now there is no commercial variety with a useful level of resistance to thrips. This is at least partly due to the lack of knowledge on resistance levels in pepper germplasm of QTLs and/or genes for resistance, and of information about resistance mechanisms to thrips in pepper. This paper describes our research aimed at developing practical and reliable screening methods for thrips resistance in pepper and at identifying pepper accessions showing a strong resistance to thrips. Thirty-two pepper accessions from four species of pepper (Capsicum annuum, C. baccatum, C. chinense and C. frutescens) and two species of thrips (Frankliniella occidentalis and Thrips parvispinus) were used in this study. Our results indicate that the laboratory based leaf disc test and the detached leaf test can be used as reliable screening methods for thrips resistance in pepper. We observed a large variation for resistance to thrips in Capsicum that can be exploited in breeding programs.

The western flower thrips [Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae)] is a major pest in pepper cultivation. Therefore, host plant resistance to thrips is a desirable trait. The objectives of this study were to determine the effect of resistance on the development of thrips and to identify metabolite compounds related to the resistance. Three highly resistant, three medium resistant, and three susceptible pepper accessions were used in this study. Adult and pre‐adult survival, developmental time, and oviposition rate were assessed. Gas chromatography‐mass spectrometry was used to identify compounds that correlate with the level of resistance to thrips. Our results show that resistance of pepper accessions has a significant effect on oviposition rate and larval mortality. Seven compounds were identified that correlate with resistance to thrips and six compounds were identified that correlate with susceptibility to thrips. Some of these compounds, such as tocopherols, were previously shown to have an effect on insects in general. Also, some specific secondary metabolites (alkanes) seem to be more abundant in susceptible accessions and were induced by thrips infestation.

Key messageA QTL for thrips resistance on pepper chromosome 6 was identified and validated. This QTL affects thrips larval development and explains 50 % of the variation.AbstractThrips is one of the most damaging pests in pepper (Capsicum). Resistance to thrips was identified in Capsicum annuum. This study was aimed at the elucidation of the genetic background of thrips resistance in Capsicum through QTL mapping. The QTL analysis was carried out for Frankliniella occidentalis resistance in an F2 population consisting of 196 plants derived from an interspecific cross between the highly resistant C. annuum AC 1979 as female parent and the highly susceptible C. chinense 4661 as male parent. Fifty-seven SSR, 109 AFLP, and 5 SNP markers were used to construct a genetic map with a total length of 1636 cM. Damage caused by larvae and the survival of first and second instar larval stages observed in a no-choice test were used as parameters of resistance. Interval mapping detected one QTL for each of these parameters, all co-localizing near the same marker on chromosome 6. Use of this marker as co-factor in a multiple-QTL mapping analysis failed to uncover any additional QTLs. This QTL explained about 50 % of the genetic variation, and the resistance allele of this QTL was inherited from the resistant parent. Thrips resistance was not linked to trichome density.

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Agrobacterium-mediated genetic transformation was applied to produce beet armyworm (Spodoptera exigua Hu¨bner) resistant tropical shallots (Allium cepa L. group Aggregatum). A cry1Ca or a H04 hybrid gene from Bacillus thuringiensis, driven by the chrysanthemum ribulose-1,5-bisphosphate carboxylase/oxygenase small subunit (Rubisco SSU) promoter, along with the hygromycin phosphotransferase gene (hpt) driven by the CaMV 35S promoter, was employed for genetic transformation. An average transformation frequency of 3.68% was obtained from two shallot cultivars, Tropix and Kuning. After transfer of the in vitro plants to the greenhouse 69% of the cry1Ca and 39% of the H04 transgenic shallots survived the first half year. After one year of cultivation in the greenhouse the remaining cry1Ca and H04 transgenic plants grew vigorously and had a normal bulb formation, although the cry1Ca transgenic plants (and controls) had darker green leaves compared to their H04 counterparts. Standard PCR, adaptor ligation PCR and Southern analyses confirmed the integration of T-DNA into the shallot genome. Northern blot and ELISA analyses revealed expression of the cry1Ca or H04 gene in the transgenic plants. The amount of Cry1Ca expressed in transgenic plants was higher than the expression levels of H04 (0.39 vs. 0.16% of the total soluble leaf proteins, respectively). There was a good correlation between protein expression and beet armyworm resistance. Cry1Ca or H04 gene expression of at least 0.22 or 0.08% of the total soluble protein in shallot leaves was sufficient to give a complete resistance against beet armyworm. This confirms earlier observations that the H04 toxin is more toxic to S. exigua than the Cry1Ca toxin. The results from this study suggest that the cry1Ca and H04 transgenic shallots developed could be used for introducing resistance to beet armyworm in (sub) tropical shallot.Abbreviations: AL-PCR -adaptor ligation PCR; Bt -Bacillus thuringiensis; cry1Ca -a synthetic gene from Bacillus thuringiensis; GUS -b-glucuronidase; H04 -a hybrid gene from B. thuringiensis; hpt -hygromycin phosphotransferase gene; LB -T-DNA left border; RB -T-DNA right border; gusA -b-glucuronidase gene.

The primary and secondary somatic embryogenesis can be used to propagate Coffea arabica L clonally.  However, the success of this propagation was depended on plant growth regulator and varieties. This study aimed to examine the possibility of 2,4-D and thidiazuron application to form primary and secondary somatic embryo to support Arabica coffee clonal propagation. The study consisted of two activities (1) 2,4-D and thidiazuron Application to Induce Primary Somatic Embryogenesis of Arabica Coffee and (2) The Application of thidiazuron in Solid and Semi-Solid Media to Induce Secondary Somatic Embryos.  The results indicated significant effect of varieties and plant growth regulator on fresh weight, number of torpedo and germinated embryo.  However, it showed no significant effect on callus formation percentage. The best medium to induce primary somatic embryogenesis depending on variety, on the treatment of 4.52 μM 2,4 -D +18.16 μM thidiazuron was the best for AS2K and Sigarar Utang varieties, S 795 at 4.52 μM 2,4-D + 9.08 μM thidiazuron, whereas Kartika at 4.52 μM 2.4-D + 13.62 μM thidiazuron.  The morphology of coffee somatic embryo was normal.  Primary somatic embryo was developed indirectly, whereas the secondary somatic embryo was directly.  The application of 9.08 μM thidiazuron  increased the percentage and number of secondary somatic embryos, hence enhancing number of Arabica coffee planlet. Keywords : Coffea arabica L, 2,4-D, thidiazuron, semi-solid media, Indirect somatic embryogenesis

<p>The Regenerated of Siam Tangerin through Somatic<br />Embryogenesis. Ali Husni, Agus Purwito, Ika Mariska,<br />and Sudarsono. Somatic embryogenesis occurs in most<br />plants that are cultured on a suitable medium in vitro.<br />Somatic embryo may arise from single cells and the embryogenic<br />cells are widely applicable in plant propagation,<br />genetic manipulation and transgenic technologies. The<br />present study was carried out to develop an effective<br />somatic embryogenesis technique to regenerate Siam<br />tangerine plants. Materials used in this study were nucellar<br />tissues of young fruits (30-90 days post anthesis). Induction<br />of embryogenic calli was done by culturing the tissues on<br />three different basal media (MS, MW and MT). Embryo<br />maturation was done on the MW medium + ABA (0; 0.1; 0.3;<br />dan 0.5 mg/l), while germination to plantlet development<br />was done on WS medium + GA3 (0, 0.1, 0.3, and 0.5 mg/l).<br />The results showed that among the three media, MW was<br />the best medium for callus induction from nucellar tissues<br />with a success rates 98% for Simadu and 100% for<br />Pontianak. The best maturation of embryo somatic was<br />done on MW medium + ABA 0.5 mg/l with success rates<br />99%, while the best medium for germination and development<br />into planlets was MW medium + 0.5 mg/l GA3 with a<br />success rate 58%.</p>