1. Thirty cotton varieties were studied. Seven parents generated 21 F1 diallel progenies. The main objective was to evaluate genotypes through oil content, fatty acids, morphological and molecular characteristics. Statistical procedures were performed with Agrobase, NCSS and NTYSS computer programmes. Correlation, heterosis, heritability, G x E interaction and stability values were obtained. Stability across four environments was analysed by five stability measures, that of Shukla, Wricke, Lin and Binns, Eberhart and Russell and the AMMI analysis. 2. Significant differences were observed for oil and fatty acids content. Oil content results revealed an average of 20.23%. The ratio for polyunsaturated:saturated fatty acid was 2:1 and for unsaturated:saturated 3:1. The predominant fatty acids were linoleic, palmitic, oleic, stearic, myristic, palmitoleic, arachidic and behenic. Palmitic fatty acid was high while oleic and stearic fatty acids were low for almost all varieties studied. Oil and fatty acid content were significantly influenced by the environment. CIM 70 and Cyto 12/74 can be selected as parents for increased oleic and stearic fatty acid and Stoneville 506 as a parent for reduced palmitic fatty acid, increased oleic, stearic and linolenic fatty acids in hybridisation. 3. ANOVA results indicated significant differences between varieties for all agronomical characteristics studied, where NTA 93-21 and NTA 93-15 were the best performers almost for all characteristics. Genetic distances for morphological (qualitative characteristics) analysis ranged from 0.18 to 0.80. Two major groups, one including many varieties from Africa and the other including varieties from the USA, were revealed. 4. AFLP analysis showed high genetic similarities (0.85 to 0.98). Varieties were distinguished according to pedigree and origin. The increased genetic similarity observed, indicates the need for the introduction of more diverse cotton material. Comparison of agronomical and AFLP markers for determining genetic diversity indicated that genetic similarities between varieties were low for agronomical compared to AFLP markers. The correlation coefficient between AFLP analysis and agronomical genetic similarities was not significant, 5. Highly significant differences between genotypes over environments were observed and NTA 93-21 crosses outperformed the seven parents for almost all characteristics. The parent Okra leaf performed poorly for many characteristics. Trial sites Ukiriguru followed by Kanziga were high yielding environments. 6. Combining ability analysis results indicated significant variation in GCA estimates among parents for different characteristics. Genotypes having high positive GCA estimates for yield components exhibited negative GCA estimates for fibre quality, excluding NTA 93-21. Some combinations indicated positive and significant SCA effects for seedcotton, boll weight, GOT and lint yield. The GCA/SCA ratios for most of the studied characteristics were larger than one. 7. Correlation among characteristics indicated highly significant positive and negative correlations. The observed high and significant GCA and SCA effects for those characteristics are promising for cotton population improvement. Positive heterosis for boll weight was observed for more than 90% of the combinations. Hybrids with high SCA values presented high values of heterosis. Heritability values for the studied characteristics were moderate to high. 8. The combined ANOVA over four environments indicated significant differences between genotypes and locations for all characteristics. The percentage contribution of location to total variation was high compared to genotype variation except for a few characteristics. Highly significant differences of G x E for lint yield and fibre strength were observed. 9. Three stability procedures (Wricke, Shukla and ASV) identified similar stable genotypes. Eberhart and Russellâs procedure, was in harmony with the above three methods but with some divergence. Cultivar superiority measure deviated from the other four measures. Therefore the procedures of Wricke, Shukla and AMMI can be applied for cotton stability studies.

The phase out of well-known chemical control products, especially soil fumigants, is a reality and biological control strategies need to be explored. Biological control rarely eliminates a pathogen from the soil, usually it reduces its numbers or ability to induce disease. However combining complementary biological control tactics may become the only tool in integrated control management for soilborne diseases. The biggest challenge will be to determine the most feasible sequence of techniques for optimal control of each pathogen, farming system and geographic area. Other factors that may have an influence on the efficacy of any bio-control strategy are host related (genetic resistance), environment related (longevity. soil type & climate) and pathogen related (virulence, inoculum density, survival). There is considerable interest in biofumigation as an alternative to synthetic soil fumigants in horticulture and agriculture. The term biofumigation usually referrers to the biocidal effects of isothiocyanates (ITCâs) released from Brassicaceous plants. It can and should however be extended to other volatile bio-substances with the same qualities like thiophene, a heterocyclic, sulphurous compound released by Tagetes spp. The rhizosphere presents a complex integrated ecosystem. Biotic and abiotic factors present, can determine the dynamics and structure of the microbial population in a specific rhizosphere. Screening different crops for rhizosphere suppression of soilborne pathogens can be a point of departure to select crops for a specific crop rotation system. A series of summer- and winter crops were evaluated for rhizosphere suppression of Ralstonia solanacearum (Race 1, Biovar III), causal agent of bacterial wilt in tobacco. Ocimum basilicum (sweet basil), Tagetes erecta (giant marigold), T. patula (dwarf marigolds), Coriandrum sativum L. (coriander) and Triticum aestivum L. (wheat cv. Inia) resulted in a significant control of the pathogen. However all Tagetes spp.had the lowest pathogen population count of all crops evaluated. A greenhouse trial conducted in 0,5 m deep soil indicated that the T. patula in combination with non-host winter crops, could reduce the pathogen population of the soil to such an extent that the disease incidence on the followup tobacco crop was 40% lower than that of the initial tobacco crop. A four-year rotation trial on a heavily infested field showed that T. patula in combination with wheat was responsible for a significantly higher tobacco yield (green leaf mass). In both greenhouse and field trials, cabbage (Brassica oleracea L. var capitata.) proved to be a latent host, suggesting that it should be avoided as a winter cash crop in tobacco fields infested with R. solanacearum.

The Modder River is a relatively small river which drains an area of 7 960 km2 in the central region of the Free State Province, South Africa and has a mean annual run-off of 184 x 106 m3. Water demand in the Modder River catchment has exceeded supply in the past which necessitated the development of two transfer schemes: 1) From the Caledon to the Modder (Caledon-Bloemfontein pipeline), and 2) The Caledon to Modder also known as the Novo transfer scheme. This study focussed on the ecological effects of the Novo transfer scheme on both the Modder and Caledon Rivers from a limnological point of view, thus excluding the human component and land-based investigations. The transfer of water from the turbid Caledon River caused an increase in turbidity in Knellpoort Dam. However, this turbidity decreased when transfer of water was terminated, and conditions returned to those prior to the transfer of the water. This increase in turbidity brought about certain effects, like limitation of underwater light penetration, and a consequent decrease of the euphotic depth. The turbidity did, however, not extend to the inflow of the dam where the Novo pump station is located and is thus not expected to increase turbidity in the Modder River. The largest fraction of sediment particles in the Caledon River, consists of very fine sand. This has implications in terms of the bioavialability of nutrients and consequently, the maximum bioavailability of nutrients in the sediment load of the Caledon River was found to 339 mg/kg N and 106 mg/kg P. The transfer of water (and nutrient-rich sediments) from the Caledon River, via Knellpoort Dam, to the Modder River caused an increase in the concentrations of TP, PO4-P, NO3-N and SiO2-Si in Knellpoort Dam. Since the effect of the inflowing water seems to be localised to the area at the inflow channel, the water quality at the Novo pump station (on the opposite side of the impoundment) was little influenced. However, if transfer takes place over a long period of time, it can have a significant impact on the nutrient concentrations of the impoundment. Similarly, if the ionic composition changes over a long period of water transfer, the algal communities in the different systems can change. In the different waters of the Novo Transfer Scheme, there are large variations in the algal composition. In the Caledon River, the Bacillariophyceae (specifically Cyclotella and Stephanodiscus spp.) dominated the phytoplankton throughout the study period. Turbulence in the river, together with high turbidity, probably limited the development of cyanobacterial blooms. In Knellpoort Dam, the algal community was dominated by Bacillariophyceae and Chlorophyceae, and Cyanophyceae numbers increased only after the transfer of nutrient-rich water from the Caledon River. This could have serious implications for the uses of the impoundment, which include water purification for drinking water and recreation, as cyanobacterial blooms can be harmful to humans and animals. In the Modder River, the algal community was dominated by Bacillariophyceae, Chlorophyceae and Cyanophyceae, and it was the same in Rustfontein Dam, an impoundment in this river used for domestic water supply and recreation. As water was not transferred to the Modder River during the study period, the effects on the invertebrate community in this river could not be determined, and possible impacts are predicted on observations made from other studies. From these, it is not expected that there will be a transfer of undesirable invertebrate species from the Caledon River. Species diversity at the transfer site is generally low, and the high flow conditions during transfer periods will limit the species diversity even more. The main concern in terms of invertebrate diversity is the potential impact of increased flow in the Modder River during periods of transfer. Based on this study, the following recommendations are made: ⢠Abstraction from the Caledon River must be done at the end of the rainy season, when turbidity levels are lower, but stream flow is still high enough. ⢠The sediment channels into the Knellpoort Dam are not very effective and alternative measures should be investigated to remove the sediment. ⢠The nutrient and turbidity status of the Knellpoort Dam must be carefully monitored to ensure that the impoundment does not become eutrophic or too turbid. ⢠When discharging the water from Knellpoort Dam into the Modder River, cognisance must be taken of the natural seasonal flow of the river, and care must be taken not to exceed the normal flow with too big a margin. Erosion measures must be put in place at the point of discharge and carefully monitored.

Summary · Ethiopian cultivars and advanced lines of bread and durum wheat were studied for their grain quality characteristics under different environmental conditions. The influence of different protein fractions, ratios and subunits on bread making quality were determined by means of HPLC. Significant correlations across diverse genotypes and environments might indicate the potential use of these techniques in breeding programmes. SE-HPLC Bread wheat · The genotypes studied expressed genetic variability in most of the important quality traits. Protein levels across the two environments were relatively low. A decrease in protein content led to an increase in mixing time. Genotypes at the lowest protein site had the longest mixing times. · The higher protein site had higher average concentrations for all fractions extracted, except for SDS soluble and insoluble LMP. · Across the two environments, the SDS soluble and insoluble polymeric proteins had a highly significant influence on quality. · The number of correlations observed increased across environments compared to individual environments. · Higher significant correlations were observed between ratios of proteins compared to that found between individual proteins. SE-HPLC Durum · Similar results to bread wheat were seen for durum genotypes tested. The lower protein environment resulted in a lower protein content and increased mixing time. · The average concentrations for SDS soluble LPP and SMP and insoluble LMP, SMP, TUPP and LUPP were higher at the high protein potential site. · The number of correlations increased across environments, than when environments were considered individually. · The magnitude of the correlations increased across environments. · Higher significant correlations were observed between ratios of protein fractions and quality traits, notably the correlations between the ratio of SDS insoluble LPP:LMP and SPP:LMP with mixograph development time (0.545*** and 0.518***, respectively). · Durum has the potential of improvement for bread making quality. Bread and durum wheat · The average flour protein content was slightly higher for durum wheat, at the higher protein site, but similar at Motta. · The mixograph development time for both wheat types was longer at Motta, than at Adet, with the mixing time for durum slightly longer than that of bread wheat at Motta. · The durum genotypes had higher average SDS soluble and insoluble LPP and SMP fractions, at both environments, compared to bread wheat. · The opposite was true for LUPP and TUPP fractions, where the bread wheat genotypes had a higher average. · The LUPP fraction and the SDS insoluble SPP displayed a direct relationship with SDS sedimentation, continuously across environments. · The averages of baking quality traits for bread and durum wheat, with the exception of SDS sedimentation, did not differ extensively. This indicated the potential application of durum wheat for comparable breadmaking utility. RP-HPLC Due to the large amount of data generated by RP-HPLC, emphasis was placed on the general trends across entries and differences between entries were not discussed. Bread wheat · A total of 38 glutenin subunits (including minor peaks and unresolved shouders) were resolved. · Forty two bread wheat gliadin peaks were differentiated. · The environmental effect was visible in entries in both variation in quantity observed and as presence or absence of subunits. · Peaks/subunits correlating with baking parameters differed across different environments. This indicated sensitivity to environmental influences. · Some correlations occurred consistently, regardless of the differences in environment. · Significant polymeric-polymeric and monomeric-monomeric as well as polymeric-monomeric correlations were observed. These interactions need to be considered when determining functionality. Correlations might be due to indirect effects. · Stepwise multiple regression can assist in determining direct relationships. It also gives an indication of the interactions excisting between protein components. · The regression models indicated the individual proteins contributing to the quality trait. Some proteins were major contibutors, explaining 59% of the variation occurring in the parameter. The most important contributors to quality remained the glutenin subunits. Durum wheat · A total of 42 glutenin subunits (including minor peaks and unresolved shouders) were resolved. · Fifty one durum wheat gliadin peaks were differentiated. · Similar results to bread wheat were obtained for durum wheat entries. · Unlike the bread wheat results, specific durum subunits influenced more than one baking parameter simultaneously. · More interactions between the different protein subunits influencing specific traits were visible. No distinct patterns were visible between the subunit type and functional property.

The primary aim of this study was to determine whether size-exclusion high performance liquid chromatography (SE-HPLC) could be used for quality prediction of South African wheat cultivars. · A bread cultivar, a cracker cultivar and two soft wheat cultivars were used in this two-year experiment. · Protein extracts of wheat flour were analysed by SE-HPLC. · SDS was used for the first protein extraction step, and the rest of the proteins were extracted by sonication. · The SE-HPLC method fractionated the storage proteins (both SDS-soluble and SDS-insoluble) into four distinct peaks of decreasing molecular size range, representing mainly larger polymeric proteins (mainly HMW-glutenins), smaller polymeric proteins (mainly LMW-glutenins), larger monomeric proteins (mainly gliadins), and smaller monomeric proteins (mainly albumins and globulins). · The wheat samples were also analysed for a total of 11 important quality characteristics. · Relationships between the amount and size-distribution of polymeric and monomeric proteins and flour quality properties were established. · The influence of different nitrogen (N) treatments on protein fractions and quality characteristics was also determined by SE-HPLC.The results showed that both the genotype and N-treatments had a significant influence on quality characteristics. · However, the genotype (cultivar effect) had a more significant influence on the protein fractions and quality characteristics than the N-treatments. · The total amounts of N applied during the treatments had a more significant eff ect on protein fractions and quality characteristics than later N-applications (N applied during the flag leave stage). · The SDS-soluble and SDS-insoluble polymeric proteins were found to be equally important in quality prediction. · The hard wheat cultivars were characterised by an increase of polymeric protein as opposed to monomeric protein. · The polymeric proteins (glutenins) were strongly positively correlated with dough strength properties, such as alveograph P/L ratio and alveograph strength. · The large monomeric proteins, which are mainly gliadins, were positively associated with the soft wheat cultivars, and had a consistently significant negative effect on quality characteristics, such as falling number (FLN), vitreous kernels (VK), alveograph P/L ratio and alveograph strength. · The large monomeric proteins showed positive correlations with single kernel weight (SK weight), single kernel diameter (SK diameter) and breakflour yield (BFLY). · SE-HPLC provided a simple and an objective test for measuring the relative size-distributions of wheat storage proteins. · SE-HPLC also proved to be very usefull in predicting quality.

The purpose of this study was to determine attitudes of the elderly towards euthanasia. The aims of this research study were achieved by gathering data from a number of elderly respondents aged 65 and older at several old age homes in the Bloemfontein area. Six old age homes were involved in this study with a slightly greater concentration coming from Bloemfontein N=89 (44.5%), while the distribution was relatively even across the other two broader residential areas N=55 (27.5%) in Heidedal, and N=56 (28%) in Mangaung. A biographical questionnaire as well as the Euthanasia Attitude Scale was used. The influence of three variables such as, race, religious beliefs and gender, on the attitudes of the elderly people towards euthanasia was investigated. One-way ANOVA analysis was used. After statistical analysis, the variable found to have the greatest influence on the attitudes of the elderly towards euthanasia was race. Other variables, religious beliefs and gender were not found to have a significant correlation to euthanasia.

Lachenalia is a small bulbous geophyte of the family Hyacinthaceae, endemic to South Africa and first described in 1787 by Jacquin. There is a large degree of variation in the genus and some species overlap morphologically with other genera such as Polyxena and Massonia , and it is very difficult to delimit the species. There are currently approximately 120 species described, but new species are frequently described. Several authors attempted to subdivide the genus (Baker, 1897; Crosby, 1986; Duncan, 1988 & 2002). Lachenalia has a tremendous cultivation potential, and 25 new cultivars have been introduced since 1966. A cytogenetic, as well as a molecular study, was conducted to try and solve problems with the classification in the genus, and to provide answers to the breeders regarding infertility problems between interspecific crosses. The chromosome numbers of a few species were determined by examining meiotic and mitotic chromosomes in order to guide the breeders in their hybridisation studies. The numbers obtained during this study were combined with results of previously studies to try and determine the original basic chromosome number(s) in the genus. Several basic chromosome numbers have been reported in the genus, i.e. x = 5/10, 7, 8, 9, 11 and 13. The majority species have a basic chromosome number of x = 7, followed by x = 8 and then x = 11. Polyploidy is common, occurring in 40% of the species in the genus. The number x = 7 has mainly diploids, 28.6% tetraploids and a few hexa - and octaploids and, therefore, represents a young mature polyploid complex. The numbers x = 8 and x = 11 both forms young polyploid complexes. According to this information, it can be concluded that x = 7 were the original basic number, from which x = 8 and x = 11 evolved. The hypothesis on the evolution of the chromosome numbers were tested by sequencing the trnL-F region of the chloroplast genome. This region was also sequenced to try and provide answers for the taxonomists on the difficult task of classifying and delimiting the genus. The phylogenetic position of the genus in relation to other liliaceous plants also needed to be determined. The basic chromosome numbers were superimposed on the cladogram, and a definite correlation between chromosome numbers and monophyletic groups were obtained. Several monophyletic clades formed, dividing the cladogram into four distictive groups: the âL. juncifoliaâ, âLachenalia 1â, âLachenalia 2â and âL. zebrinaâ groups, and several subgroups. The position of these groups and subgroups confirms the hypothesis that x = 8 evolved from x = 7. It also indicated that several hybrids prevail within the genus, explaining the delimitation problems and the variation in basic chromosome numbers. The genus Polyxena are included within the Lachanalia clade, indicating that this genus should either be included in the genus, or Lachenalia should be split into several genera. Polyxena could also have introduced new chromosome numbers and variation in the genus by hybridisation. The cladogram confirms that Polyxena is the closest relative of Lachenalia , followed by Massonia and Whiteheadia . This study indicated that the cytogenetic and molecular data support one another. The trnL-F region is useful to study phylogenetic relationships on genus or higher taxonomic levels, but the addition of other genes will probably provide more answers for the classification and evolution of the genus.

The aim of the study was to learn more about the expression of b-1,3-glucanase during the resistance response of wheat to the RWA (Diuraphis noxia)(Mordvilko). The different resistance genes (Dn1, Dn2 and Dn5) used in the study would shed more light on the possibility that b-1,3-glucanase expression is a universal biochemical resistance mechanism with regard to RWA. Tugela DN (Dn1) and Dn2 plants resulted in a similar expression pattern of b-1,3-glucanases after RWA infestation. The Dn1 and Dn2 cultivars had very high differential b-1,3-glucanase activity induction, which occurred much sooner compared to the infested susceptible plants. Wheat plants with the Dn5 resistance gene induced b-1,3-glucanase activity to a much lower level compared to the other two resistant lines. Northern blot analyses confirmed that the increase in b-1,3-glucanase activity and peptide levels in the Western blot analyses was due to increased transcription of b-1,3-glucanase genes. The induced b-1,3-glucanases were located intercellularly in the vascular bundle and mesophyll cell walls of wheat leaves. Intracellular the b-1,3-glucanases were primarily located in the chloroplast grana with low labelling found in the cytoplasm. Chloroplasts were isolated and fractionated to scrutinize results obtained with the localisation study. b-1,3-glucanase activity and Western blot analysis of chloroplast fractions verified these results with a 35 kDa b-1,3-glucanase residing in the chloroplast membrane bound fraction. These b-1,3-glucanases could play a role in the protection of the chloroplast of infested resistant plants.

A taxonomic revision of Cryptolepis R.Br. (Apocynaceae, Periplocoideae) in southern Africa is presented. This revision comprises investigations into the micromorphology of pollen, translators, leaf anatomy, leaf epidermal surfaces and seed coat surfaces; macro-morphology of the plant parts; nomenclature, geographical distribution and ecological characteristics of the six species indigenous to southern Africa. The investigations resulted in descriptions with appropriate nomenclature and the compilation of an identification key for the six species. All available type specimens related to Cryptolepis in southern Africa were studied. Where holotype specimens could not be located lectotypes were designated from available isotypes or syntypes. Where no isotypes or syntypes could be located, neotypes were declared. In cases where only syntypes had been given by authors of species names, lectotypes were declared. Cryptolepis is widely distributed throughout the northern parts of southern Africa, with the largest concentration of species in the north-east of the region. Some species, such as C. oblongifolia, are common, while others have very restricted distribution ranges. C. delagoensis, for instance, is known from only six localities in southern Africa. Only C. decidua occurs in the desert and semi-desert habitats in the north-west of southern Africa, while the other five species inhabit savannah, sand forest, riverine -, afromontane - and coastal vegetation in the eastern parts of the region. In southern Africa Cryptolepis consists of slender climbers, occasionally small suffrutices or branching shrubs with white latex and interpetiolar ridges with dentate colleters. Leaves are opposite, decussate or rarely fascicled. A combination of leaf anatomy and leaf surface characteristics proved to be taxonomically useful for distinguishing the southern African species. The fruit consists of paired follicles. Seeds of Cryptolepis are adapted to anemochoric dispersal through a coma of hair at the micropylar end. All southern African species can be differentiated from each other using cellular arrangement and primary and secondary sculpture of their seed coat surfaces. Floral characteristics are taxonomically useful for distinguishing Cryptolepis from related genera. Cryptolepis is characterized by a distinct corolla tube, with corolla lobes always longer than the corolla tube, corona lobes arising just above the middle of the corolla tube, and usually included in the corolla tube, and stamens arising at the lower third of the corolla tube, with interstaminal discs always present. Two, semi-inferior, apocarpous ovaries are present. The styles unite to form a compound style and pentagonal style-head, on which five translators are formed by epithelial cells in grooves alternating with the stamens. The anthers are fused to the style head, forming a gynostegium. In the five species that occur in the eastern parts of the region flowers are arranged in cymes. Prominent, paired colleters are found at the inner bases of the sepals. The corona lobes may be oblong, clavate, deltoid or awl-shaped. The corona lobes are always included in the corolla tube, where they touch or fit tightly, forming a dome which closes off the lower corolla tube. Pollen characteristics and translator shape are similar for all five species and have little taxonomic value. C. decidua differs from the eastern species in that its flowers are solitary. The colleters at the inner sepal bases are replaced by trichomes. The corona lobes are filiform, do not form a dome over the lower corolla tube and may be exserted from the corolla tube mouth. Pollen tetrad shape and translator shape and size differ markedly from those of the other species. All these unique characteristics in C. decidua suggest that this species may not belong in Cryptolepis.

Kenaf (Hibiscus cannabinus L.) is an important fiber crop world wide, and has a great potential for its multipurpose uses. It could play a significant role in future fiber supply in Southern Africa. Six diverse cultivars were selected from 14 genotypes as parental lines and crossed in a full-diallel method. The parental lines and 30 F1 hybrids were assessed and various traits were measured. General combining ability (GCA) was lower than specific combining ability (SCA). This indicated that non-additive genetic effects were more important for the inheritance of those characteristics. High heritability in the broad sense was recorded for the yield related characteristics (FPM, DPM, PH, BD, MD). Heterosis was widely expressed in the F1 generation. Many crosses showed both mid-parent and high-parent heterosis for the yield characteristics (FPM, DPM, PH, BD, MD). It can be concluded that a hybrid breeding program could effectively improve kenaf yield. Nine kenaf cultivars were evaluated for stability in two locations across two years. Highly significant differences were observed between the locations and years for fresh yield, defoliated yield and dry yield. The location under irrigated conditions had a higher yield value than under dry land conditions. Genotype x environment interaction was significant in this study. Four different types of stability parameters and correlation analyses were used to evaluate kenaf cultivar stability. In the combined analysis, El Salvador and Everglades 41 were the cultivars that tended to have highest dry yield in the various environments. Tainung 2 was the most unstable cultivar for the measured characteristics.