Thesis (MSc. Agriculture (Agronomy)) -- University of Limpopo, 2013 / Maize (Zea mays L.) is the third most important cereal crop after wheat and rice in the world. Maize/legume intercropping system has become one of the solutions for food security among small scale maize producers due to unaffordability of chemical nitrogenous fertilizers and limited access to arable land. A study was conducted to determine the effect of maize/dry bean and maize/lablab intercropping on maize grain yield and soil fertility status. A field experiment was conducted during 2010/2011 and 2011/2012 growing seasons at the University of Limpopo experimental farm. Treatments included sole maize (ZM 521, an improved open pollinated variety, ex- CIMMYT), sole lablab (Rongai, indeterminate cultivar), sole dry bean (DBS 360, indeterminate Type II cultivar), maize/dry bean and maize/lablab intercrops arranged in randomized complete block design with five replications. Phosphorus (P) was applied on sole and intercropped maize at the rate of 30 kg P/ha in the form of superphosphate (10.5%P) at planting and 40 kg N/ha of nitrogen (N) was applied in the form of Limestone Ammonium Nitrate (LAN) (28%N) on both sole and intercropped maize four weeks after plant emergence. For maize and dry bean, grain yield, yield components and biomass were determined. Only biomass yield was measured for lablab. Soil samples were collected for soil analysis at the beginning and the end of the experiment The results showed that maize/lablab intercropping yielded significantly (P<0.05) lowered maize grain (1259.3 kg/ha) than sole maize and maize/dry bean intercropping which yielded maize grain of 2093.7 kg/ha and 2156.3 kg/ha, respectively. Sole dry bean yielded significantly (P <0.05) higher dry bean grain (1778.5 kg/ha) than intercropped dry bean (691.8 kg/ha). Rongai was only flowering by the time maize and dry bean matured hence only maize yield is reported for the Maize/lablab intercrop. Maize/dry bean intercropping was advantageous to sole cropping with a Land Equivalent Ratio (LER) of 1.42. The partial Land Equivalent Ratio (PLER) for maize in maize/lablab intercropping was 0.60. Dry bean was outcompeted by maize as calculated aggressivity value was positive at +0.64.The highest monetary value was achieved in sole dry bean and the lowest monetary value was found in intercrop dry bean. Soil TN, P, K, Ca, Mg and Na were reduced by both sole cropping and intercropping systems. Intercropping with lablab is likely to significantly lower maize yield under dryland conditions. Key words: dry bean, grain yield, Intercropping, lablab, maize, smallholder, soil fertility.

Bibliography: leaves 200-223. / xii, 225, [15] leaves, [19] leaves of plates : ill. (some col.), maps (some col.) ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, Dept. of Plant Science, 1995?

"January 2003" / Includes bibliographical references (leaves 172-204) / xx, 204 leaves : ill. ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, Dept. of Animal Science, 2003

Bibliography: leaves 200-223.

Diverse forage mixtures have improved resilience to drought, improved persistence, ability to adapt to changing environmental conditions, reduced fertilizer costs, improved root mass and greater soil carbon sequestration but do they improve forage and animal production. The objective was to determine if complex native forage mixtures provide superior nutritional quality throughout the grazing season as compared to simple native mixtures. Three studies were conducted in 2007 at Swift Current, SK to evaluate forage production potentials, nutritive qualities and in vitro dry matter digestibility of native and tame forage species common to or having potential in Southwestern Saskatchewan. In study one, plots were seeded in 2006 on Chernozemic Orthic Brown Swinton Loam soils and consisted of 11 native and three tame monoculture species common to southwestern Saskatchewan. Clippings at a 5 cm stubble height occurred on June 20 and every 28 days after until October 10. Forage DM production, in vitro OMD, NDF, ADF, ADL, CP, Ca and P concentrations were measured. As species matured, production and OMD declined (P¡Ü0.05) but NDF, ADF and ADL concentrations increased (P¡Ü0.05). There were harvest date by species differences (P¡Ü0.05) in forage production and nutritional qualities of C3 and C4 grass and legume species. Study two examined the in situ CP, NDF and DM disappearance of six selected species harvested in the fall. EDNDF and ADDM values did not differ (P>0.05) among C3 grasses. The C4 grasses had higher (P<0.05) EDNDF and EDDM and the legume, Canadian milkvetch had the highest (P<0.05) EDDM but lowest EDNDF. Study three occurred in 2005, 2006 and 2007 to determine if complex native forage mixtures had superior forage and animal production as compared to simple forage stands. Grazing occurred from June through August to achieve 60% utilization. Animal weights and available, cage and residual forage yields were taken to determine production and utilization. Forage production and quality did not differ (P>0.05) between simple and complex forage mixtures but animal production (AUD ha-1) was higher on complex native mixtures. Overall results showed; 1) C3 and C4 grass and legume species have different growth patterns and qualities that can improve forage quality and degradability of the stand throughout the grazing season, 2) forage and animal production benefits associated with complex native forage mixtures largely depend on environmental conditions like temperature and moisture.

Dry bean (<i>Phaseolus vulgaris</i>) is currently being introduced for rainfed production in the Dark Brown soil zone in Saskatchewan. Insufficient water is one of the major factors limiting crop production in this soil zone. Ten pinto bean genotypes (Othello, Agate, GH196-2, 6315, 5325, Earliray, Fiesta, ISB82-354, UI 111 and Nodak) were exposed to drought stress in the field to study their rooting pattern under drought stress. Three pinto bean genotypes (Othello, Agate and GH196-2) with an extensive root system in the deeper soil layers and three (Earliray, Fiesta and ISB82-354) with a less extensive root system were exposed to drought stress and nonstress conditions in the growth room and in the field to study the relationship between rooting pattern and seed yield. In addition, three indeterminate pinto bean genotypes (Othello, Nodak and Fiesta) and three determinate genotypes (Agate, Agassiz and Earliray) were exposed to a soil moisture gradient to study the effects of soil moisture level on seed yield and other agronomic traits. Othello, Agate and GH196-2 had an extensive root system in the deeper soil layers, whereas Earliray, Fiesta and ISB82-354 had a less extensive root system in the deeper soil layers. An extensive root system in the deeper soil layers was associated with increased soil moisture depletion at those depths. Shoot dry mass, total root dry mass, mean root length density and root:shoot ratio were the same for the ten pinto bean genotypes. Pinto bean genotypes with an extensive root system (Othello, Agate and GH196-2) in the deeper soil layers had higher seed yield compared to genotypes with a less extensive root system (Earliray, Fiesta and ISB82-354) in the deeper soil layers in the field and in the growth room. Due to insufficient drought stress in the field, the rooting pattern of the six pinto bean genotypes was the same under irrigation and rainfed conditions. In the growth room, pinto bean genotypes with an extensive root system showed a stronger recuperative ability after a severe drought stress compared to genotypes with a less extensive root system. Root traits were positively correlated with seed yield under adequate soil moisture or where drought stress was relieved before maturity. Soil moisture deficit reduced number of pods per plant, plant height, seed weight, seed yield and seed nitrogen concentration of both determinate and indeterminate pinto bean genotypes. Indeterminate pinto bean genotypes had, on average, higher mean seed yield and showed a greater seed yield response to increasing soil moisture availability compared to determinate genotypes. However, the difference in seed yield of the two groups was small under high drought stress, except in the case of one very early maturing determinate genotype.

Some researchers have proposed that carbon isotope discrimination (CID) be used to indirectly select for grain yield and transpiration efficiency in C₃ plants. To determine the effectiveness of CID in indirectly selecting for grain yield and transpiration efficiency, ten diverse lentil (<i>Lens culinaris Medikus</i>) genotypes, ten diverse wheat genotypes (eight spring wheat (<i>Triticum aestivum </i>L.) and two durum wheat (<i>Triticum turgidum</i> L.)), and ten diverse canola (<i>Brassica napus L</i>.) genotypes were grown in a greenhouse at 80, 50, and 30% field capacity and in the field at several locations in Saskatchewan in 1992 and 1993. In the greenhouse, above ground dry matter was harvested at 80% flowering, and data collected on water use, transpiration efficiency, weight of dry matter at flowering, and CID on dry matter at flowering analyzed. In the field, samples were collected from leaves at flowering, leaves at maturity, and kernels at maturity, and analyzed for CID. In all species in the greenhouse, genotypic differences in CID were observed under all three water regimes. For lentil and wheat, the 80% field capacity water regime provided the largest differences in CID, whereas the 30% field capacity water regime provided the largest differences in CID for canola. In all three crops, CID and transpiration efficiency were independent under all three water regimes, or when averaged across water regimes and years. The correlation between CID and dry matter at flowering was inconsistent across water regimes and years. In the field, genetic variability for CID at different growth stages and in different plant organs was observed in all three species. The genotype by environment interaction for CID was low compared to that for grain yield. In addition, the correlations between grain yield and CID in lentil and spring wheat were positive, but inconsistent across locations and years. The broad-sense heritability for grain yield was greater or similar to the broad-sense heritability of CID measurements. These results suggest that under these conditions CID could not be used effectively to indirectly select for grain yield in lentil, spring wheat, or canola.

Experiments were conducted to determine the outcrossing rate, the inheritance of markers and establish a basic linkage map in grasspea, <i> Lathyrus sativus </i>L. The outcrossing rate in a white-flowered line of grasspea ranged from 1.7 to 2.7% among eight combinations of gene frequency and location. The outcrossing rate in this study (2.2 ± 0.7%) suggests that individual lines of grasspea should be maintained in isolation to maintain their genetic integrity. Inheritance and linkage were determined for one morphological, 11 isozyme and 72 RAPD markers in five F₂ populations (all RAPD markers were in one F₂ population). The inheritance of flower colour was monogenic with colour dominant over white. The isozymes, ACO-1, ACO-2, AAT-1, AAT-2, EST-6, FDH, LAP-1, PGD-2, SKDH and TPI-1, were codominantly expressed with monogenic inheritance. The isozymes LAP-1 and PGD-2 segregated in a non-Mendelian ratios in the crosses PI 426891.1.3 x PI 283564c.3.2 and PI 426891.1 x PI 172930.4, respectively. The isozymeEST-3 was monogenically inherited and dominantly expressed. Most RAPD markers segregated in a 3:1 ratio. Marker UBC368_425/655 segregated in a co-dominant fashion. The RAPD markers UBC304₈₃₁, UBC304₉₆₄, UBC308₉₉₀, UBC322₁₄₃₂, UBC328₈₃₁, UBC332₁₁₁₈, UBC3321₁₅₈₁, UBC333₆₁₇, UBC349<sub>752<?sub>, UBC365₁₀₁₃ and UBC388₄₅₉ showed distorted segregation. In two F₂ populations, PI 283564c.3 x PI 426885.2 and PI 358601.5 x PI 173714.5, a linkage between AAT-2 and SKDH was reconfirmed. In the cross PI 426891.1.3 x PI 283564c.3.2, one morphological, three isozyme and 71 RAPD markers were mapped resulting in the delineation of 14 linkage groups including 69 markers (1 morphological, 3 isozyme and 65 RAPD markers). The total genome length covered by these 75 markers (69 linked and six unlinked) was about 864 cM. Considering cost, simplicity and abundance, RAPD analysis was more efficient than isozyme analysis in developing linkage map.

Diverse forage mixtures have improved resilience to drought, improved persistence, ability to adapt to changing environmental conditions, reduced fertilizer costs, improved root mass and greater soil carbon sequestration but do they improve forage and animal production. The objective was to determine if complex native forage mixtures provide superior nutritional quality throughout the grazing season as compared to simple native mixtures. Three studies were conducted in 2007 at Swift Current, SK to evaluate forage production potentials, nutritive qualities and in vitro dry matter digestibility of native and tame forage species common to or having potential in Southwestern Saskatchewan. In study one, plots were seeded in 2006 on Chernozemic Orthic Brown Swinton Loam soils and consisted of 11 native and three tame monoculture species common to southwestern Saskatchewan. Clippings at a 5 cm stubble height occurred on June 20 and every 28 days after until October 10. Forage DM production, in vitro OMD, NDF, ADF, ADL, CP, Ca and P concentrations were measured. As species matured, production and OMD declined (P¡Ü0.05) but NDF, ADF and ADL concentrations increased (P¡Ü0.05). There were harvest date by species differences (P¡Ü0.05) in forage production and nutritional qualities of C3 and C4 grass and legume species. Study two examined the in situ CP, NDF and DM disappearance of six selected species harvested in the fall. EDNDF and ADDM values did not differ (P>0.05) among C3 grasses. The C4 grasses had higher (P<0.05) EDNDF and EDDM and the legume, Canadian milkvetch had the highest (P<0.05) EDDM but lowest EDNDF. Study three occurred in 2005, 2006 and 2007 to determine if complex native forage mixtures had superior forage and animal production as compared to simple forage stands. Grazing occurred from June through August to achieve 60% utilization. Animal weights and available, cage and residual forage yields were taken to determine production and utilization. Forage production and quality did not differ (P>0.05) between simple and complex forage mixtures but animal production (AUD ha-1) was higher on complex native mixtures. Overall results showed; 1) C3 and C4 grass and legume species have different growth patterns and qualities that can improve forage quality and degradability of the stand throughout the grazing season, 2) forage and animal production benefits associated with complex native forage mixtures largely depend on environmental conditions like temperature and moisture.

M. Tech. Chemistry / Sutherlandia frutescens is a popular indigenous South African medicinal plant which has been identified to re-establish itself on acid rock mine dumps. Medicinal plants such as S. frutescens are harvested from the wild and widely used for primary health care. The primary objective of the study was to determine the effect of soil contamination on the secondary metabolites profile of the plant.