Tomato seeds and skins acquired from the byproduct of a local tomato processing facility were studied for supercritical fluid extraction (SFE) of phytochemicals. The extracts were analyzed for lycopene, beta-carotene, alpha-carotene, alpha-tocopherol, gamma-tocopherol, and delta-tocopherol content using high-performance liquid chromatography-electrochemical detection and compared to a chemically extracted control. SFEs were carried out using CO(2) at seven temperatures (32-86 degrees C) and six pressures (13.78-48.26 MPa). The effect of CO(2) flow rate and volume also was investigated. The results indicated that the percentage of lycopene extracted increased with elevated temperature and pressure until a maximum recovery of 38.8% was reached at 86 degrees C and 34.47 MPa, after which the amount of lycopene extracted decreased. Conditions for the optimum extraction of lycopene from 3 g of raw material were determined to be 86 degrees C, 34.47 MPa, and 500 mL of CO(2) at a flow rate of 2.5 mL/min. These conditions resulted in the extraction of 61.0% of the lycopene (7.19 microg lycopene/g).

The genetic diversity of two diploid wheat species, Triticum monococcum and Triticum urartu (2n=2x=14), was assessed using random primers and the polymerase chain reaction (PCR). Electrophoretic analysis of the amplification products revealed a higher incidence of polymorphism in T. urartu than T. monococcum. Pair-wise comparisons of unique and shared polymorphic amplification products, were used to generate Jaccard's similarity coefficients. These were employed to construct phenograms using an unweighted pair-group method with arithmetical averages (UPGMA). The UPGMA analysis indicated a higher similarity among T. monococcum than T. urartu. Analysis of RAPD data appears to be helpful in determining the genetic relationships among genotypes.

Soybean cyst nematode (SCN) is a major soybean yield-limiting pest. The present study was conducted to map broad-based SCN resistance loci from the cultivar 'Hartwig'. Two-hundred F2∶3 lines derived from the cross 'Williams 82' x 'Hartwig' were screened with a fourth-generation SCN inbred and 56 polymorphic molecular markers. Allele states and phenotypes were analyzed using stepwise regression and the model selection was made at P [Symbol: see text] 0.01. Four unlinked RFLP markers (A006, A567, A487, A112) were associated with SCN resistance and the partial coefficient of determinations (R(2)) were 91%, 1%, 1%, and 1%. We have mapped a new, major SCN resistance locus (A006) and three minor loci (A567, A487, A112). This complete mapping will accelerate the transfer of broad-based resistance without linkage drag and aid in the determination of relationships among various SCN-resistant germplasm sources.

We report on a rapid high-frequency somatic embryogenesis and plant regeneration protocol for Zea mays. Maize plants were regenerated from complete shoot meristem (3-4 mm) explants via organogenesis and somatic embryogenesis. In organogenesis, the shoot meristems were directly cultured on a high-cytokinin medium comprising 5-10 mg x L(-1) 6-benzylaminopurine (BAP). The number of multiple shoots produced per meristem varied from six to eight Plantlet regeneration through organogenesis resulted in just four weeks. Callus was induced in five days of incubation on an auxin-modified Murashige and Skoog (MS) medium. Prolific callus, with numerous somatic embryos, developed within 3-4 weeks when cultured on an auxin medium containing 5 mg 2,4-dichlorophenoxyacetic acid x L(-1). The number of multiple shoots varied from three to six per callus. Using R23 (Pioneer, Hi-Bred, Johnston, Iowa), the frequency of callus induction was consistently in excess of 80% and plant regeneration ranged between 47 and 64%. All regenerated plantlets survived in the greenhouse and produced normal plants. Each transgenic plant produced leaves, glumes, and anthers that uniformly expressed green fluorescent protein (GFP). The GFP gene segregated in the pollen. Based on this data it is concluded that the transgenics arose from single-cell somatic embryos. The rate of transfer DNA (T-DNA) transfer to complete shoot meristems of Zea mays was high on the auxin medium and was independent of using super-virulent strains of Agrobacterium.