High frequency plant regeneration from microspore-derived embryos of ornamental kale (Brassica oleracea L. var. acephala)

The aim of this work was to study the effect of solid medium, developmental stage, embryonic age, cold treatment and additives to the medium on plant regeneration from microspore-derived embryos in four F₁ hybrids of ornamental kale (Brassica oleracea L. var. acephala). The results showed that all of the cultivars responded best when the embryos were cultured in solidified B5 medium with 1% agar. Optimal regeneration was gained when cotyledonary embryos were cultured for 25 days. Cold treatment significantly improved plant regeneration with a frequency of up to 79.0% under 4 °C for 2 d or 5 d. The addition of 3.0 or 5.0 mg/L silver nitrate (AgNO₃) increased the frequency of plant regeneration. In the Zhouyehongxin cultivar, the frequency of plantlet development reached 84.4%. The addition of activated charcoal reduced embryo hyperhydricity.     

The culture of isolated microspores of ornamental kale (Brassica oleracea var. acephala) and the importance of genotype to embryo regeneration

The culture of isolated microspores of kale (Brassica oleracea var. acephala) was studied including the importance of genotype to embryo regeneration, medium composition chiefly the sucrose concentration and the use of colchicine, simultaneously medium renovation. It was initiated using 29 different genotypes as donor plants. Embryos were induced from six of the kale genotypes and these corresponded to the more out-bred genotypes. Embryogenesis was achieved using four different combinations of culture media: (a) microspores initially cultured in NLN medium supplemented with 13% (w/v) sucrose (NLN-13) for 48 h, followed by transfer to fresh NLN-13 medium; (b) microspores cultured for 48 h in NLN-13 medium supplemented with colchicines (50 mg/L) followed by transfer to unsupplemented NLN-13 medium; (c) microspores cultured for 48 h in NLN-16 medium supplemented with colchicines (50 mg/L) followed by transfer to unsupplemented NLN-16 medium; (d) microspores cultured for 48 h in NLN-16 medium supplemented with colchicines (50 mg/L) followed by transfer to unsupplemented NLN-13 medium. The embryos obtained from four of the genotypes developed into plantlets and these regenerated plants have been successfully transplanted to soil.     

Photosynthetic and growth responses of juvenile Chinese kale (Brassica oleracea var. alboglabra) and Caisin (Brassica rapa subsp. parachinensis) to waterlogging and water deficit

Chinese kale (Brassica oleracea var. alboglabra) and Caisin (Brassica rapa subsp. parachinensis) are leafy vegetable crops grown in south-east Asian countries where rainfall varies dramatically from excess to deficit within and between seasons. We investigated the physiological and growth responses of these plants to waterlogging and water deficit in a controlled experiment in a glasshouse. Juvenile plants were subjected to waterlogging or water deficit for 19 days in case of Chinese kale and 14 days in case of Caisin and compared with well-watered controls. Caisin tolerated waterlogging better than Chinese kale because it produced hypocotyl roots and gas spaces developed at the stem base. In Chinese kale, waterlogging reduced plant fresh weight (90%), leaf area (86%), dry weight (80%) and leaf number (38%). In contrast, waterlogging had no impact on leaf number in Caisin and reduced plant fresh and dry weights and leaf area by 60–70%. Water deficit reduced leaf area, fresh weight and dry weight of both species by more than half. Leaf number in Chinese kale was reduced by 38% but no effect occurred in Caisin. Water deficit increased the concentration of nitrogen in the leaf dry matter by more than 60% in both species and the leaf colour of water deficient plants was dark green compared with the leaf colour of well-watered plants. Soil water deficit delayed flowering of Caisin while waterlogging accelerated it. Thickening and whitening of the cuticle on the leaves of Chinese kale probably increased its ability to retain water under drought while Caisin adjusted osmotically and Chinese kale did not. Waterlogging and water deficit had strong effects on leaf gas exchange of both Brassica species. Water deficit closed the stomata in both species and this was associated with a leaf water content of 9 g g⁻¹ DW. In contrast, waterlogging reduced conductance from 1.0 to 0.1 mol H₂O m⁻² s⁻¹ in direct proportion to changes in leaf water content, which fell from 11 to 5 g g⁻¹ DW. This separation of the effects of water deficit and waterlogging on conductance was reflected in transpiration, internal CO₂ concentration and net photosynthesis. In conclusion, Chinese kale and Caisin showed rather different adaptations in response to waterlogging and water deficit. Caisin was more tolerant of waterlogging than Chinese kale and also showed evidence of tolerance of drought. There is genetic variation to waterlogging within the Brassica genus among the leafy vegetables that could be used for cultivar improvement.     

Weed competition in cauliflower (Brassica oleracea L. var. botrytis) in the Jordan Valley

A field experiment was carried out in 1996/1997 and repeated in 1997/1998 at the Jordan University Research Station located in the central Jordan Valley to determine the effect of weed competition on growth and yield of cauliflower Brassica oleracea var. botrytis cv. “White Cloud”. The treatments consisted of either allowing weeds to infest the crop or maintaining plots weed-free for increasing durations after transplanting. Results showed that longer periods of weed/cauliflower competition greatly reduced crop growth and head yield. Average reductions in shoot dry weight and head yield were 81% and 89%, respectively. Maintaining a weed-free crop for any period after transplanting increased cauliflower growth and head yield compared with the weed-infested control. Weed competition for 14 days after transplanting reduced cauliflower average head yield by 41%. To determine the critical period of weed competition and the influence of weed infestation on cauliflower head yield the Gompertz and logistic equations were fitted to data representing increasing duration of weed-free and weed-infested periods, respectively. Based upon an arbitrary 5% level of head yield loss, the critical period of weed competition occurred at 0–38 days after cauliflower transplanting which corresponded with the rapid increase in weed biomass. Results indicated that early weed removal is necessary to prevent yield loss.     

Production of inter-section hybrids between Primula filchnerae and P. sinensis through ovule culture

Inter-section hybrids were obtained in the reciprocal crosses between Primula filchnerae (2n = 2x = 24) of Sect. Pinnatae and P. sinensis ‘Fanfare’ (2n = 2x = 24) of Sect. Auganthus by rescuing ovules on half-strength (1/2) Murashige and Skoog's (MS) medium supplemented with 50 g l⁻¹ sucrose, 2.5 g l⁻¹ gellan gum, 0.1 mg l⁻¹ α-naphthaleneacetic acid (NAA), 0.1 mg l⁻¹ 6-benzyladenine (BA) and 50 mg l⁻¹ gibberellic acid (GA₃). In ovule culture, germination occurred with radicle elongation but no plumule was observed. The radicle kept on the initial medium showed root proliferation with callus formation. When the calluses were transferred to (1/2)MS media containing 30 g l⁻¹ sucrose and 3 g l⁻¹ gellan gum, without plant growth regulators (PGRs) or with 1 mg l⁻¹ zeatin and 0.1 mg l⁻¹ NAA, plantlets were regenerated. The plants thus obtained were confirmed to be hybrids through flow cytometry (FCM) and random amplified polymorphic DNA (RAPD) analyses. The hybrid obtained when P. filchnerae was used as the maternal parent was diploid, whereas hexaploid hybrid was obtained when using P. sinensis as the maternal parent. The hexaploid hybrid might be produced through chromosome doubling of a triploid originated from the fertilization of P. sinensis with unreduced pollen of P. filchnerae.     

Changes in kale (Brassica oleracea L. var. acephala) carotenoid and chlorophyll pigment concentrations during leaf ontogeny

There has been recent market interest in “baby” salad greens. However, little information exists on the nutritional differences between immature “baby” greens and produce traditionally sold at the fully mature stage. Kale (Brassica oleracea L. var. acephala D.C.) contains high levels of lutein and β-carotene, which possess important human health properties. Kale was grown in a controlled environment and pigments were measured in young (<1 week), immature (1–2 weeks), mature (2–3 weeks), fully developed (3–4 weeks) and senescing (>4 weeks) leaves using high-performance liquid chromatography (HPLC). Significant differences were observed for all pigments during leaf development. Pigment accumulation followed a quadratic trend, with maximums occurring between the 1st and 3rd week of leaf age. The highest concentrations of lutein measured 15.1 mg/100 g fresh mass and occurred in 1–2 week old leaves. The remaining pigments reached maximum levels at 2–3 weeks (β-carotene at 11.6 mg/100 g; chlorophyll a at 251.4 mg/100 g; and chlorophyll b at 56.9 mg/100 g fresh mass). Mature fully expanded kale leaves accumulated higher carotenoid concentrations than immature or “baby” leaves, with senescent leaves having the lowest carotenoid concentrations. Harvesting kale leaves at a mature stage of development resulted in maximum carotenoid values. Cultural management practices that increase carotenoid concentrations would be expected to improve nutritional quality for fresh markets.     

6-Benzylamino purine stimulates in vitro shoot organogenesis in Eucalyptus erythronema, E. stricklandii and their interspecific hybrids

In vitro bud and shoot organogenesis was investigated for the ornamental plants Eucalyptus erythronema var. erythronema, E. stricklandii and their interspecific hybrids cv. ‘Urrbrae Gem’ and ‘Hybrid 2.5’ by using 0.0, 0.1, 0.25, 0.5 or 1.0 μM BAP on apex and leaf explants. Callus developed on all explants and increased with all concentrations of BAP without significant differences between BAP concentrations. Buds formed on apex and leaf explants of E. erythronema and E. cv. ‘Urrbrae Gem’ especially with 1.0 μM BAP, but these buds rarely developed into shoots. Bud clusters formed on E. erythronema and E. cv. ‘Urrbrae Gem’ apex and leaf explants whereas E. stricklandii and ‘Hybrid 2.5’ produced fewer, individual buds on the explant. Shoots regenerated from apex explants of all genotypes with all levels of BAP, whereas few shoots of any genotype regenerated from leaf explants regardless of the number of buds formed. Shoots from apex explants could be multiplied successfully. Light microscopy showed meristems developed within the callus, and at the callus and bud surfaces. However, few shoots developed considering the level of bud and meristem formation. This report is the first for successful shoot organogenesis and multiplication in an ornamental eucalypt.     

Plant regeneration from in vitro cultured leaves of Lanzhou lily (Lilium davidii var. unicolor)

Lanzhou lily (Lilium davidii var. unicolor) is one of the best lilies which are edible in China but the efficient shoot regeneration system has not been developed. The purpose of the present study is to establish an efficient and reproducible protocol for induction of shoots in vitro from L. davidii var. unicolor leaves. Shoot regeneration from in vitro cultured leaves of L. davidii var. unicolor was tested on the 26 media based on NN [Nitsch, J.P., Nitsch, C., 1969. Haploid plants from pollen grains. Science 163, 85–87] basal medium, containing different concentrations of thidiazuron (TDZ) in combination with different concentrations of α-naphthaleneacetic acid (NAA). Shoot organogenesis occurred directly from the leaves without forming callus. Shoot regeneration mainly occurred from the cuts across the midvein and the base of the leaf explants. The highest frequency of regeneration (93.3%) and the largest number of shoots per leaf (3.83) were obtained on NN basal medium supplemented with 0.5 mg l⁻¹ TDZ and 1.0 mg l⁻¹ NAA. All the regenerated shoots formed complete plantlets on half-strength MS [Murashige, T., Skoog, F., 1962. A revised medium for rapid growth and bioassays with tobacco tissue cultures. Physiol. Plant 15, 473–497] basal medium containing 0.1–0.5 mg l⁻¹ indole-3-butyric acid (IBA) with in 30 days, and 92% of the regenerated plantlets survived in the soil. This study will be useful for Agrobacterium-mediated transformation and exploitation of somaclonal variation of Lanzhou lily.     

Development of ITS sequence based SCAR markers for discrimination of Paphiopedilum armeniacum, Paphiopedilum micranthum, Paphiopedilum delenatii and their hybrids

Paphiopedilum armeniacum, Paphiopedilum micranthum and Paphiopedilum delenatii are endangered orchid species. These three Paphiopedilum species and their hybrids are difficult to distinguish morphologically. In this study, rDNA-ITS (internal transcribed spacer) sequences were used to design species-specific SCAR (sequence characterized amplified regions) markers to distinguish P. armeniacum, P. micranthum, P. delenatii and their respective hybrids. The developed markers efficiently amplified 600 bp DNA product for P. armeniacum and its hybrids (SCAR-600armF/Pap-ITS2R), 300 bp product for P. delenatii and its hybrids (SCAR-300delF/Pap-ITS2R) and 700 bp product for P. micranthum and its hybrids (SCAR-700micF/Pap-ITS2R). The effectiveness of designed species-specific markers was also confirmed by using multiplex polymerase chain reaction amplification with a combination of developed three SCAR markers.     

Effect of nitrogen form and radiation on growth and mineral concentration of two Brassica species

Three greenhouse experiments were carried out to determine the growth, yield, nitrate, total N and S concentration in shoots, and water uptake of hydroponically grown Brassica rapa L. subsp. nipposinica var. chinoleifera and Brassica juncea L. In each experiment, daily photosynthetically active radiation (PAR) level was 5.0 mol m⁻² (low), 6.8 mol m⁻² (medium) or 9.0 mol m⁻² (high). Plants were supplied with nutrient solutions having equal N concentrations of 11 mM in different forms: 100% NH₄, 50% NH₄ + 50% NO₃, and 100% NO₃. Nitrogen supplied as 100% NH₄ reduced fresh and dry shoot biomass, leaf area, and leaf number in both Brassica species, especially at low and medium PAR levels. In both Brassica species, S concentrations were highest, while nitrate concentrations were lowest in leaves of plants grown at N supplied as 100% NH₄. No differences in leaf nitrate concentrations were observed between 50% NH₄ + 50% NO₃ and 100% NO₃ treatments. Low and high PAR levels increased the nitrate concentrations and decreased the N/S ratio in leaves of both crops compared to medium PAR level. Fresh shoot biomass was maximized in Brassica rapa when PAR level was above the medium value and nitrate was supplied in the nutrient solution as NO₃ or as a mixture of 50% NO₃ and 50% NH₄. The highest fresh shoot biomass of Brassica juncea was observed in all nutrient solution treatments at high PAR level.     

Direct regeneration of plants derived from in vitro cultured shoot tips and leaves of three Lysimachia species

The regenerability of three ornamental species—Lysimachia christinae, Lysimachia rubinervis and Lysimachia nummularia ‘Aurea’, were investigated using in vitro leaves and shoot tips. 6-Benzylaminopurine (BAP) and α-naphthalene acetic acid (NAA) added to Murashige and Skoog (MS) medium were tested for their effect on organogenesis. On the medium, shoot regeneration occurred directly without callus formation. In these species, L. christinae developed the highest regeneration rate and numbers of shoots/explant from shoot tips (100%, 12.25) and leaf bases (100%, 13.01) on the MS medium containing 3.0 mg l⁻¹ BAP and 0.1 mg l⁻¹ NAA. For L. rubinervis, the highest shoot induction rate and number of shoots/explant were obtained from shoot tip (100%, 16.87–17.20) on the MS medium with 0.1 mg l⁻¹ NAA and 3.0–5.0 mg l⁻¹ BAP. L. nummularia ‘Aurea’, however, showed the highest regeneration rate and number of shoots/explant (100%, 12.73) from leaf bases on MS medium supplemented with 1.0 mg l⁻¹ BAP and 0.1 mg l⁻¹ NAA. All in vitro shoots rooted well on half macronutrient MS medium containing 0.1 mg l⁻¹ NAA. After acclimatization, transplanted plantlets grew normally and flowered in the field.     

Ethylene influences development and flowering of Ptilotus spp. in vitro and ex vitro

The genus Ptilotus has immense potential for ornamental horticulture but its commercial development has been hindered by propagation limitations. Poor seed quality and germination are reported. Cutting propagation is limited by cutting supply as the juvenile phase of Ptilotus is short. Micropropagation has been used in an attempt to overcome these difficulties but explants become floral in vitro and this causes plantlets to elongate. Ethephon has been used to control flowering of stock plants of many ornamental species. This study investigated the effect of ethephon applied to young (3-week-old, deflasked from tissue culture) and mature (1-year-old) Ptilotus plants in a greenhouse. A system of applying gaseous ethylene at 0, 100, 200 and 300 mg l⁻¹ to the headspace of in vitro plantlets in glass jars was developed and the response of in vitro plantlets to ethylene studied. One-year-old Ptilotus plants were treated with 500 mg l⁻¹ ethephon 2 days before pruning or 1 or 2 weeks after pruning. Ethephon application 2 days before pruning decreased the number of inflorescences and increased the number of shoots (compared to the control) but was phytotoxic. Ethephon applications of 150 or 300 mg l⁻¹ applied weekly or fortnightly to 3-week-old plants deflasked from tissue culture reduced plant height and number of inflorescences and at low concentrations increased the number of new shoots. A fortnightly application at 150 mg l⁻¹ is recommended. Previous reports on the effects of ethylene on inflorescence production on plantlets in vitro are limited. Our study showed that exposure of in vitro plantlets of P. nobilis to ethylene gas at 100 mg l⁻¹ for 1 h significantly increased the number of shoots and plant height but this did not occur for plantlets of P. spicatus. Plantlets of P. spicatus exposed to transient ethylene at 200 and 300 mg l⁻¹ showed significantly greater rooting (52.4%) than the control (13.6%).     

Effect of different fertilisation and irrigation practices on yield,nitrogen uptake and fertiliser use efficiency of white cabbage (Brassica oleracea var. capitata L.)

The effect of different fertilisation (i.e. broadcast application and fertigation) and irrigation practices (tank sprinkler and drip irrigation) on yield, yield quality (nitrate content), nitrogen uptake of white cabbage (Brassica oleracea var. capitata L.) and the potential for N losses was assessed on sandy-loam agricultural soil. ¹⁵N-labelled fertiliser was used as a tracer. It was found that different practices significantly affected yield, nitrate content in plants, N uptake, as well as fertiliser use efficiency. The highest yield (93 t ha⁻¹), plant N uptake (246 kg ha⁻¹), and fertiliser use efficiency (42%) were obtained under treatment with broadcast fertilisation with farmer's practice of irrigation (tank sprinkler). The N surplus after harvest was −41 kg N ha⁻¹, indicating the lowest potential for N losses. Treatment by fertigation and drip irrigation covering 100% of the crop's water requirements did not result in the highest yield as expected (72 t ha⁻¹), the N surplus after harvest was about +38 kg ha⁻¹. The lowest yield (58 t ha⁻¹), fertiliser use efficiency (30%) and hence the highest potential for N losses (N surplus after harvest +68 kg ha⁻¹) were found in treatment with broadcast fertilisation and drip irrigation covering 50% of the crop's water requirements.     

High-frequency embryogenesis,regeneration of broccoli (Brassica oleracea var. italica) and analysis of genetic stability by RAPD

High-frequency somatic embryogenesis and shoot regeneration of broccoli (Brassica oleracea var. italica) were achieved. Cotyledon and hypocotyl explants from four varieties of broccoli were cultured on MS and modified MS media (mMS, supplemented with PG-96 organic components) with different combinations of growth regulator. The effects of genotypes, different explants, growth regulator combinations, organic components and AgNO₃ on induction of calli and shoots were evaluated. The optimal media for inducting calli/shoots and roots were mMS medium containing 3% (w/v) sucrose and 0.8% (w/v) agar supplemented with NAA at 0.5 mg l⁻¹, 6-BA at 3.0 mg l⁻¹, AgNO₃ at 4.0 mg l⁻¹ and MS medium containing 3% sucrose and 0.8% (w/v) agar supplemented with NAA at 0.2 mg l⁻¹, respectively. The callus induction percentages were over 90% in all four varieties; shoot induction percentage was 92.5% and the average number of shoot per explant was 4.1 from cotyledon explant in variety Bishan. In this study, we established high-efficient embryogenesis and shoot regeneration system of broccoli and analyzed genetic stability of regenerants at DNA level using RAPD molecular marker. Out of 62 arbitrary primers screened using PCR amplification, 79 polymorphic bands were amplified from 20 primers. The results demonstrated the genetic stability of regenerants from the same variety.     

Interspecific variations in seed germination of Corylopsis

This study was initiated to investigate the differences in germination percentages and rates between Corylopsis coreana Uyeki and Corylopsis sinensis var. calvescens Rehder & E.H. Wilson following a warm stratification (WS) and cold stratification (CS), and to study the effect of different WS temperatures interacting with different durations of CS. Warm stratification at 10 °C, 15 °C, 20 °C, and 25 °C was given for 1 month (1 M 10 °C, 15 °C, 20 °C, and 25 °C WS) followed by 0 M, 1 M, 2 M, and 3 M of CS at 5 °C (0 M, 1 M, 2 M, 3 M CS) and seeds were germinated in an air conditioned greenhouse maintained at 18.5 °C/18 °C. On average, less than 1% of C. coreana seeds germinated when sown without any WS and CS or with 1 M 15 °C, 20 °C, and 25 °C WS without CS treatment. However, 26% C. coreana seeds germinated after 1 M 10 °C WS without any CS treatment. Germination was not affected by WS temperatures when followed by 2 M 5 °C CS. It is concluded that C. coreana exhibited low seed germination at 10 °C and that this temperature could be considered the upper limit of CS for C. coreana. Only 2 M CS was required for more than 90% seeds to germinate. However, C. sinensis var. calvescens required longer than 3 M CS for more than 29% seeds to germinate. This clearly shows that there is an interspecific variation in optimum dormancy-breaking requirements.     

Aneuploid strawberry (2n = 8x + 2 = 58) was developed from homozygous unreduced gamete (8x) produced by second division restitution in pollen

Unreduced gamete formation is significant in the evolutionary development of complex polyploidy series found in wild strawberry, genus Fragaria (Rosaceae). Also, it is important for genetics and breeding in strawberry plants to elucidate the mechanism of unreduced gamete formation. The objective of this study was to search for ploidy anomalies resulting from artificial diploid × octoploid crosses, and examine the mechanism through which these unreduced gametes were produced. Five everbearing cultivars of Fragaria vesca L. diploid (2n = 2x = 14) were crossed with pollen from six June-bearing cultivars of Fragaria × ananassa Duch., octoploid (2n = 8x = 56). A total of 3000 mature seeds, 100 from each of the 30 parental combinations were sown at 23 °C/20 °C (day/night) under artificial lighting with a 16 h day. The seedlings were transplanted to pots and grown in a greenhouse. Reproductive and morphological observations, flow cytometry analyses, chromosome counts and DNA analyses using CAPS markers were performed to identify the genetic background of the offspring. Most of the seed (79%) did not germinate or died soon after germination. Of the seedlings produced, 7% seemed to be pure F. vesca based on morphological characteristics, flow cytometry analyses and chromosome counts; 14% were pentaploids (2n = 5x = 35), 0.1% were hexaploids (2n = 6x = 42), and 0.03% (one individual) was aneuploid (2n = 8x + 2 = 58). Electrophoresis banding patterns obtained by CAPS marker analysis were heterozygotic in the 8x pollen parent but homozygotic in the aneuploid progeny. Judging from the chromosome counts and the CAPS marker analysis, the aneuploid was the result of a homozygous unreduced pollen grain (8x) crossed with an incomplete chromosome compliment from the egg. Because of the homozygosity, the unreduced male gamete must have been derived from second division restitution (SDR) in the octoploid pollen parent.     

Effects of the antiauxin PCIB on microspore embryogenesis and plant regeneration in Brassica rapa

An efficient protocol to improve microspore embryogenesis and plant regeneration in Brassica rapa was established. The antiauxin p-chlorophenoxyisobutyric acid (PCIB) was used to enhance microspore embryogenesis and plant regeneration without an intervening callus phase. All the 4 tested genotypes responded positively to PCIB. The optimum concentration of PCIB application was found to be 40 μM in NLN-13 medium, which resulted in a 3.4- to 6.2-fold increase in the number of embryos (8.27–19.2 embryos per bud) and a 9.6-fold increase (21.33%) in the plant regeneration frequency in comparison with the controls. Heat-shock treatment by incubation at 35 °C for 1 day was more efficient in inducing embryogenesis in the 2 tested genotypes. The embryos, produced in NLN medium supplemented with 40 μM PCIB and transferred at the 21-day-old followed by a treatment at 4 °C for 5 days, reached the highest direct plant regeneration rate of 58.00%.     

Heterosis for mineral elements in single cross-hybrids of cabbage (Brassica oleracea var. capitata L.)

Cabbage (Brassica oleracea var. capitata L.), a cross-pollinated crop, was observed to exhibit strong heterosis for high yield; better plant stand; early maturity; larger and more uniform heads; uniformity in head compactness; and disease tolerance in F₁ hybrids. However, information on the heterosis for mineral elements such as Fe, Zn, Cu, Mn, K and Ca although is not available to the best of our knowledge but it is important as it is likely to influence the plant and subsequently the human nutrition. Therefore, an attempt was made to estimate the heterosis for mineral elements in cabbage. Significant mean square for parents and hybrids was observed for all minerals under study which indicated the prevalence of sufficient variation. The parents 83-2, Pride of Asia, Red Cabbage, AC-204 and MR-1 were found to have the potential for use in cabbage quality breeding programme as they exhibited higher hybrid effects for Fe, Zn, Cu and Mn content. The single cross-hybrids, i.e. 83-2 × AC-204; Pride of Asia × C-2 and Pride of Asia × Red Cabbage; Pride of Asia × MR-1; 83-2 × Red Cabbage; and Pride of Asia × AC-204 and 83-2 × MR-1 were the best for Fe and Zn; Fe and Cu; Zn and Mn; Cu and Zn; and Cu, respectively. This study revealed clearly that none of the hybrids excelled for all the minerals suggesting the significance and need for multiple crossing breeding approaches, i.e. three way cross-hybrid, double cross-hybrid, population improvement, synthetics, composites, etc., for increasing the mineral concentration in cabbage head, i.e. “Breeding Cabbage for Higher Mineral” (Biofortification) without losing the vigour advantage for yield and other traits of economic importance to combat mineral deficiencies in human beings and plant systems.     

Genetic diversity in mainland and island populations of the endangered Pancratium maritimum L. (Amaryllidaceae) in Tunisia

Tunisian Pancratium maritimum L. populations are at present endangered and represented by scattered individuals as a result of coastal habitat destruction caused by urbanization and overharvesting for its significant ornamental interest. Nineteen populations growing in mainland and island habitats were sampled for allozyme diversity to assess their genetic diversity and structuration using seven isozymes revealed by starch gel electrophoresis. The species exhibited relatively high levels of genetic diversity (the mean A_p = 1.37, P = 37.4%, and H_e = 0.100), indicates a preferentially outcrossing mating system.