Cowpea, Vigna unguiculata (L.) Walp is an excellent source of protein, vitamins and minerals and a major food crop many parts of Africa. Optimal production levels are hampered by insect pests and diseases. Biotechnological techniques such as tissue culture and genetic engineering can aid in the development of varieties with resistance to insect pests and diseases. The objective of this study was to investigate conditions necessary for the development of a reproducible tissue culture system that can be applied to regenerate transformed cells from culture. The in vitro manipulation of cowpea using Murashige and Skoog (MS) medium, auxins and cytokinins resulted in the formation of callus and rhizogenesis. Calli that were formed were separated into six classes based on color and texture. Yellowish friable callus, yellowish compact, soft yellowish callus and green and white were composed of largely vacuolated cells and were non-regenerative. Friable green callus was the most prevalent callus type and could form of roots in some hormone combinations. Green spots were formed on hard compact green callus. The green spots became nodular, forming root primordia and ultimately giving rise to roots. None of the six calli types gave rise to the formation of shoots. Embryogenic callus was induced from cowpea explants cultured on MS medium supplemented with dicamba and picloram. Embryogenic suspension cultures were initiated from callus induced on MS supplemented with 3.0 mg/L dicamba or picloram and conditions for maintenance of embryogenic suspension cultures were evaluated. Somatic embryos were formed in suspension cultures. Attempts to convert and germinate the somatic embryos resulted in the formation of callus or formation of appendages on the somatic embryos or in the death of the embryos. The appendages formed roots on prolonged culture. Further research is needed to determine appropriate optimal conditions for embryo conversion and germination and ultimately plant recovery from culture.

Conifer species are subjected to major time constraints in tree improvement because of their long regeneration cycle and large sizes. However, integration of developing biotechnologies could significantly reduce this time limitation in tree breeding programs. In this regard, somatic embryogenesis (SE) offers a great potential in commercially important Turkish red pine (Pinus brutia TEN.) for rapid production of larger number of clones as well as capture of greater genetic gains. In this study, seven collections were done to sample precotyledonar zygotic embryos for induction of embryogenic tissue (ET) from 15 clones located in Antalya. Afterwards, abscisic acid, carbohydrates, polyethylene glycol (PEG), and gellan gum were tested to obtain mature somatic embryos in maturation experiments. Analyses of variance showed a significant variation among collection dates (43.1% of total variance) and clones studied (18.8% of total variance) for induction of ETs. Overall initiation frequency of ET in this study was 11.6% with clonal range of 4.7 &amp / #8211 / 24.1%. Of those tested maturation treatments, 80&amp / #956 / M ABA, sucrose and maltose at 3 and 6%, 3.75% PEG combined with 1% gellan gum were found to be suitable for maturation of somatic embryos in Turkish red pine. Sixty nine somatic embryos were obtained from Clone 22, which was one of tested clones. Induction frequencies could be further improved by using different basal media and/or manipulating media components, such as plant growth regulators. For proper maturation of somatic embryos, embryogenic lines need to be screened to find suitable lines, which are developmentally responsive to ABA treatment.

Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniv. / Härtill 4 uppsatser.

Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniv., 2007. / Härtill 5 uppsatser.

The aim of this research is to explore the influence of magnetic field on early somatic embryos (ESEs) of spruce and pine. The magnetic field is gradual. This is important for the experiment, each cluster of ESE was exposed to magnetic field of different intensity. The resulting report of this experiment consists of the comparison between various methods of image analysis and the difference in growth of ESEs due to different exposure to magnetic field and surrounding temperature. Enclosed is a proposal of ESE size computing algorithm from a given image.