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The number of chloroplasts per guard cell pair and the stomatal length of seventeen anther-derived plants obtained from three pepper donor genotypes were recorded. The haploid plants showed significantly fewer chloroplasts and shorter stomatal length than the diploid plants. Although both characters were positively correlated with the ploidy level, chloroplast number resulted a more reliable method compared to stomatal length to distinguish haploid from diploid in vitro-grown plantlets. The stomatal length values showed either significant variation among androgenic plants with the same ploidy or overlapping values between haploid and diploid individuals. On the contrary, the values for chloroplast number were more stable permitting discrimination of haploid from diploid plantlets regardless of their genetic background. Early ploidy estimation based on chloroplast counts of in vitro-grown plantlets may hasten pepper breeding programs utilizing anther-derived doubled haploids.

Kanamycin resistant plants of Solarium melongena L. (eggplant) cv. Picentia were obtained following the cocultivation of leaf explants with Agrobacterium tumefaciens. A disarmed binary vector system containing the neomycin phosphotransferase (NPTII) gene as the selectable marker and chloramphenicol acetyltransferase (CAT) as a reporter gene was utilized. In vitro grown plants were used as sources of explants to produce transgenic plants on selective medium containing 100 mg/l kanamycin. The transformation and expression of the foreign genes was confirmed by DNA hybridizations, leaf disc assays, and by measuring NPTII and CAT enzyme activities. This technique is simple, rapid, efficient, and transgenic eggplants of this commercial cultivar have been transferred to soil where they have flowered and set seed.

Abstract:  A modified gene of Bacillus thuringiensis var. Tolworthi (Bt), encoding a coleopteran insect-specific CryIIIB toxin, was transferred via Agrobacterium tumefaciens to the female parent of the eggplant commercial F1 hybrid ‘Rimina’. One-hundred and fifty eight transgenic plants were regenerated and tested by PCR and NPTII expression assays. The presence of the CryIIIB toxin in leaf extracts was demonstrated in 57 out of 93 transgenic plants tested by DAS-ELISA assay. High Bt-expressing plants contained a 74-kDa protein cross-reacting with serum anti-CryIIIB toxin. Twenty three out of 44 S. melongena plants tested by insect bioassay showed significant insecticidial activity on neonate larvae of Colorado Potato Beetle (CPB). The Bt transgene and the toxic effect on CPB larvae were transmitted to progenies derived by selfing. Thus, transgenic Bt eggplants represent a very effective means of CPB pest control.

The effects of basal media, growth regulators and gelling agents on the morphogenetic response of eleven Cucumis melo L. var. reticulatus and inodorus genotypes were examined. Regeneration was achieved from cultured cotyledons of all genotypes and the morphogenic response was affected by the genetic background. Among the combination of factors tested, MS basal medium supplemented with 2.8 µM 6-benzyladenine (BA) and 1.0 µM abscisic acid (ABA) solidified with agar gave the highest frequency of shoot regeneration.