The performance of four California and 11 eastern cultivars of Fragaria×ananassa Duchesne in Lamarck, and 12 elite F1 hybrids of Fragaria×ananassa with F. virginiana Miller in their immediate background was evaluated in a producer's field with and without methyl bromide-chloropicrin fumigation. Averaged across all genotypes, plants in nonfumigated soils had 43% fewer runners, 18% smaller fruit, and 46% lower yields than did plants on fumigated soil. They also had an average of 27% fewer crowns, 49% more root discoloration, significantly fewer fine roots, and showed symptoms of the black root rot syndrome. The most commonly isolated pathogens from discolored roots were Pythium sp., Rhizoctonia sp., Idriella lunata P.E. Nelson & K. Wilh., and the root-knot nematode (Meloidogyne hapla Chitwood). The performance of all genotypes was enhanced by fumigation, although the F. virginiana hybrids performed comparatively better than the other cultivars on nonfumigated soils.
Lupinus albus ssp. graecus, L. Fabaceae (Boiss. and Spruner) Franco and P.Silva, is being studied at the TEI of Heraklion since 1998 as a new plant with potential use in floriculture and ornamental horticulture. The plant has been recorded botanically; however, little is known about its physiology and genetic profile. Lupinus albus ssp. is a herbaceous annual plant 10 to 20 cm tall, growing at roadsides, field margins, vineyards, and olive groves up to 700 m altitude. The leaves are 5 to 11 cm wide, palmate shaped in alternate orientation, with five to nine leaflets 10 to 18 mm wide, all arising from the same point. The flowers are borne in terminal or lateral spike-like racemes 10 to 20 cm long. Florets are 15 mm long, dark blue occasionally with a white patch, stamens forming a tube. Pods are 60 to 70 mm long,with four to six black-spotted seeds. In the present work, seed germination studies were conducted combining chilling pretreatments with physical scarification (scratching). Mature seeds chilled at 5 °C for 6 weeks germinated readily (83%) when scarified with sand paper. Furthermore, we tested the effects of several plant growth regulators (chlorocholine chloride, paclobutrazol, maleic hydrazide and Ethrel 48) on young plants of Lupinus in order to obtain compact pot plants with more flowering racemes. Paclobutrazol at 5 and 10 mg/L achieved the best retardation effect, but did not affect flowering. In another trial with different potting media,the commercial potting soil proved the most suitable for growing lupins satisfactorily. It is concluded that Lupinus albus spp. graecus L. need further investigation in order to establish the best cultural conditions for its growth and development. Furthermore, due to its high genetic variability, selection and genetic improvement is required for optimal results.
A research program is being conducted to support the development of superior varieties of Ixodia achillaeoides for cut flower production. This species is an everlasting daisy in the Asteraceae, which is produced on a woody perennial bush and is currently both harvested from the wild and cultivated in Southeastern and Western Australia. Ixodia shows a high degree of variation in plant form, flower characteristics, and flowering dates throughout its geographic distribution. In our assessment program, seedlings are screened for a range of morphological and flowering characteristics, and clonal selections are established under cultivation to assess suitability to row culture. The goal is the development of selections with known flowering characteristics and disease tolerance for fresh and dried flower markets and for flowering pot plants. Description is given of assessment criteria for selection of varieties for dried and fresh markets. Seventy selected varieties are currently being assessed in randomized block plantings at two sites in South Australia. Preliminary results and descriptions are presented for superior selections made for dried flower markets. The postharvest performance of selections for fresh markets will be discussed. Research on control of flowering will be presented.
The Mediterranean region is a center of great plant diversity, harboring around 25,000 plant species, more than 20% of them endemic. Since the last Lebanese flora record in 1966, the country has experienced habitat fragmentation and destruction, due to overgrazing, overexploitation of natural resources, and urban expansion. A large number of Lebanese tree species have unexplored economic potential as either ornamental or medicinal plants. This study aimed at exploring the effects of two nitrogen fertility treatments on the growth and water use of 2-year-old Cercis siliquastrum seedlings. C. siliquastrum seeds were collected from different locations and mother trees in Lebanon in mid-Aug. 2001. Two-year old plants were then transplanted into 3-gal. containers and were randomly assigned to one of two N fertility programs, 25 ppm or 100 ppm. Plants from all redbud sources were significantly taller in the low N treatment and had significantly higher RGR than plants growing at 100 ppm N. On the other hand, plants growing at 100 ppm N level had significantly higher LAR and lower NAR than plants growing at 25 ppm N. There were significant differences in LAR and plant heights among the different sources. Water use was conducted monthly. It ranged from 3.6 × 10-4 to 1.3 × 10-3 g·cm Ht-1 per hour at 25 ppm and from 2.6 × 10-4 to 1.3 × 10-3 g·cm Ht-1 per hour at 100 ppm N through the experiment.