Thesis (M.Sc. (Agronomy )) --University of Limpopo, 2007 / Intercropping is the growing of two or more crops simultaneously on the same field, and it is a common traditional practice among resource-poor farmers throughout the Limpopo Province of South Africa. Field studies were conducted at two locations in the province namely, the University of Limpopo experimental farm at Syferkuil, and a farmer’s field at Dalmada during the 2002/2003 growing season, to determine patterns of nodulation in cowpea and lablab varieties under sole culture and in an intercropping system with maize, variety SNK2147 and also to assess biomass accumulation and grain yielding abilities of the component crops in the system. The experiments were established as a randomized complete block design with three replications at each location. Treatments examined were sole maize, two cowpea cultivars: Bechuana white and Glenda; two lablab cultivars, Rongai and Common. The legumes were intercropped alternately within 90 cm inter-row spacing of maize, thus creating a distance of 45 cm between the maize and the legume rows. Cropping system had no effect on cowpea grain yield at Syferkuil, but at Dalmada cowpea yield was reduced. Maize grain yield was significantly affected by the cropping system at both Syferkuil and Dalmada. At both locations, the yields of all the intercropped maize were lower than those of the sole crop maize. The dry matter production of different cropping systems was generally similar during the different sampling dates. / the National Research Foundation,and the Gauteng Department of Agriculture Conservation and Environment

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.

Thesis (M.Sc (Plant Production)) --University of Limpopo, 2015 / Information on the performance of the maize and pigeonpea intercropping system under dryland conditions of South Africa is scanty. The aim of this study was to determine the optimum P level and productivity of pigeonpea and maize under the dryland intercropping system. Five P rates (0, 15, 30, 45, and 60 kg P ha-1) were applied to both sole and pigeonpea intercropped with maize in a randomized complete block design with 4 replicates. Growth parameters and yield and yield attributes of pigeonpea and maize were measured to determine performance of both crops. There were significant differences in grain yield of pigeonpea as influenced by P rates in both seasons. Highest grain yields of 781 kg ha-1 during 2009/10 and 894 kg ha-1 during 2010/11 were obtained at P rate of 45 kg ha-1. Cropping system significantly influenced grain yield of pigeonpea in 2010/11 season with 37.1% higher pigeonpea grain yield from intercropped plots than in sole pigeonpea plots. There was 21.8% increase in grain yield of pigeonpea across two seasons as influenced by P rate. Maize grain yield showed little response to P rate only during the first season. However, highest maize grain yield of 1699 kg ha-1 was obtained at 60 kg P ha-1 during the 2009/10 season. Maize grain yield was only significantly influenced by cropping system during the 2010/11 season where sole plots achieved higher grain yield of 4148 kg ha-1 compared to 3297 kg ha-1 from intercrop plots. The results revealed that P application increased grain yield of pigeonpea significantly, especially in intercropped plots. The calculated total land equivalent ratio (LER) for the two crops gave positive and higher than one values, which suggests a favourable grain yield advantage for maize/pigeon pea intercrop.

Under terminal water deficit, the impact of stem carbohydrate remobilization has greater significance because post-anthesis assimilation is limited, and grain growth depends on translocation of carbohydrate reserves. The working hypothesis of this thesis is that increases in stem carbohydrates facilitate tolerance to terminal drought in wheat. The goals of this thesis are to examine this hypothesis using physiological and genetic tools; identify genes that are related to QTL for stem carbohydrate; work with wheat and barley breeders to integrate findings into the breeding program of the Department of Agricultural and Food Western Australia. The physiological data of three drought experiments (two years in a glasshouse and one year in the field) suggested the maximum level of stem water soluble carbohydrate (WSC) is not consistently related to grain weight, especially, under water deficit. The patterns of WSC accumulation after anthesis differed depending on variety and suggested that WSC degradation and translocation have different genetic determinants. Most of the carbohydrates in stem WSC in wheat are fructans. Because 1-FEH gene was an important gene in fructan degradation, the three copies of this gene (1-FEH w1, 1-FEH w2 and 1-FEH w3) were isolated from the respective genomes of bread wheat. In addition, the genes were mapped to chromosome locations and coincided with QTL for grain weight. The results of gene expression studies show that 1-FEH w3 had significantly higher levels in the stem and sheath which negatively corresponded to the level of stem WSC in two wheat varieties in both water-deficit and well-watered treatments. Strikingly, the 1-FEH w3 appeared to be activated by water deficit in Westonia but not in Kauz. The results suggest that stem WSC level is not, on its own, a reliable criterion to identify potential grain yield in wheat exposed to water deficit during grain filling. The expression of 1-FEH w3 may provide a better indicator when linked to instantaneous water use efficiency, osmotic potential and green leaf retention, and this requires validation in field grown plants. In view of the location of the contribution to grain filling of stem WSC, this is a potential candidate gene contributing to grain filling. The numerous differences of intron sequences of 1-FEH genes would provide more opportunities to find markers associated with the QTL. A new FEH gene was partially isolated from Chinese Spring and the sequence was closely related to 1-FEH genes. This gene, FEH w4, was mapped to 6AS using Chinese Spring deletion bin lines. The polymorphism of this gene was found between different bread varieties using PCRs and RFLPs, and this allowed the gene to be mapped to two populations of Hanxuan 10 × Lumai 14 and Cranbrook × Halberd. In the population of Hanxuan 10 × Lumai 14, it was close to SSR marker xgwm334 and wmc297 where the QTL of thousand grain weight and grain filling efficiency were located. This result indicated this gene might be another possible candidate gene for grain weight and grain filling in wheat.

No description available.

Studies were conducted in 2011 and 2012 to determine if narrow row corn (Zea mays L.) and/or greater plant populations could affect yield, time to silking, and other physiological characteristics. Main plots of six hybrids were arranged as a randomized complete bock design with three replications. Split plots were row widths of 76-cm (wide rows) and 20-cm rows on 76-cm spacing (twin rows). Split-split plots were target plant populations of 75 000 and 111 000 plants ha-1. Corn was no-till seeded into soybean stubble near Lexington, KY in 2011 and 2012. Year interacted with most factors analyzed in the study. This was expected, given the extreme differences in weather. 2011 ASI (days) approached zero as plant population increased in wide rows in two out of four hybrids. ASI response to plant population in twin rows was not significant for any hybrid. In 2011, yield was greater in twin rows than wide rows. For significant equations, in 2011 grain yield increased as plant population increased, but in 2012 grain yield decreased as plant population increased, across both row widths. Kernel number per ear decreased as plant population increased in 2011 and 2012, but at different rates for wide and twin rows.

Corn (Zea mays L.) defoliation experiments have been conducted for more than 120 years. However, there is limited data on the effect of row width on defoliation in modern hybrids. A two-year experiment was conducted in Lexington, Kentucky with two hybrids (113 relative maturity (RM) and 120 RM), two row widths (38 and 76 cm) and a combination of defoliation timings and severities: 0% defoliation (control), V7-100%, V14-50%, V14-100%, R2-50% and R2-100%. No yield difference among hybrids was observed in 2012. Yields were 26% greater in 38-cm rows than 76-cm rows in 2012. For 2013, corn yield for 38-cm was 10% greater, but hybrid, row width and defoliation interacted. Lowest yields were caused by V14-100% followed by R2-100%. Defoliations of V14-50% and R2-50% reduced yields in some cases. Complete defoliations at V7 did not reduce yields in most comparisons. Light interception below 80% during the critical period was enough to attain maximum yields in defoliated plants. Kernel number and kernel weight were most reduced by V14-100% and R2-100% defoliations, respectively. There is a potential for narrow rows to reduce grain yield losses after a defoliation event, when compared with wide rows.

The objective of this study was to evaluate the effect of plant densities, nitrogen levels and foliar diseases control on grain yield and seed quality of irrigated rice. An experiment was conducted in Santa Maria RS Brazil, during 2003/2004 growing season aiming to evaluate the effects, plant populations, nitrogen levels and fungicide application on grain yield (Chapter I) and seed quality (Chapter II) of irrigated rice. Were evaluated grain yield and seed quality under three plant densities (150, 265 and 380 plants m-2), five nitrogen levels (0, 40, 80, 120 and 160 kg ha-1) with and without fungicide application. There was no triple interaction among the parameters evaluated. Higher plant populations resulted in fewer tillers per plant and seeds per panicle increasing interspecific competition and grain yield was not significantly affect as result os yield components compesation. Nitrogen increased seed yield up to 97 kg ha-1 wich was not affected by plant population and an hanced the nutritional quality as result of increased protein content. Diseases control had a positive effect on grain yield and quality as well as of the rice seeds by reducing its incidence and increased germination percentage. / Com o objetivo de avaliar a influência da população de plantas, doses de nitrogênio e controle de doenças sobre a produção e qualidade de grãos e sementes de arroz irrigado foi conduzido um experimento em campo na Universidade Federal de Santa Maria, RS, no ano agrícola 2003/2004. Avaliou-se a produtividade (Capítulo I) e a qualidade de grãos e sementes (Capítulo II) em função de três populações de plantas (150, 265, 380 plantas m-2), cinco doses de nitrogênio (0, 40, 80, 120 e 160 kg ha-1 de N) e o controle ou não de doenças da parte aérea. Para todas as avaliações realizadas não se verificou interação tríplice. O incremento da população de plantas diminui o número de colmos por planta e o número de grãos por panícula aumentando a competição interespecífica. A produtividade não é influenciada pela população de plantas de 150 a 380 plantas m-2, pois os componentes da produção se compensam. A aplicação de nitrogênio contribui incrementando a produção até 97 kg ha-1 de N, não sofrendo influência da população de plantas, bem como melhorando a qualidade nutricional do produto, pois se verifica um aumento no teor de proteína com o aumento da dose de N. O controle de doenças influencia positivamente a produção e qualidade de grãos e sementes de arroz através da redução da incidência e elevação do poder germinativo de sementes de arroz.

Orientador: Maurício Dutra Zanotto / Banca: Edson Seizo Mori / Banca: José Geraldo Carvalho do Amaral / Banca: João PauloTeixeira Whitaker / Banca: Juliana Parisotto Poletine / Resumo: Realizou-se o presente trabalho, com o objetivo de avaliar a produtividade média de grãos (kg.ha-1) de linhagens de mamona (Ricinus communis L.) e estimar os parâmetros para a adaptabilidade e estabilidade fenotípicas. As avaliações da época 1 foram realizadas entre novembro de 2006 à junho de 2007 e na época 2, de março à agosto de 2005 nos municípios de Araçatuba, Botucatu, Ilha Solteira, Penápolis e São Manuel - SP, sob delineamento de blocos ao acaso com três repetições e parcela útil de 10 m2. Foram realizadas análises de variância individuais para cada local, conjunta dos cinco locais para cada época e, posteriormente as médias foram comparadas pelo teste de Scott e Knott (1974) a 5% de probabilidade. Observou-se significância para a característica avaliada em todas as análises e, devido à interação significativa entre épocas, locais e linhagens foram realizadas análises de adaptabilidade e estabilidade fenotípicas considerando-se como ambiente as épocas de semeaduras segundo metodologia proposta por Finlay e Wilkinson (1963). Na época 1 com relação à produtividade destacaram-se as linhagens 1, 6, 8, 15, 16 e 18. Quanto aos parâmetros para a adaptabilidade e estabilidade fenotípicas as linhagens 3, 13 e 18 apresentaram adaptabilidade geral e estabilidade média. Na época 2, com relação aos mesmos parâmetros, as linhagens 1, 2, 4, 7, 10, 11, 12, 14, 15, 16, e 19 apresentaram maiores produtividades, predominância de adaptabilidade específica à ambientes favoráveis e estabilidade baixa. Para as duas épocas de semeaduras as linhagens 1, 6, 8, 15 e 16 apresentaram-se como superiores em produtividade. / Abstract: This work was carried out to evaluate average grains yield (kg ha-1) of castor bean (Ricinus communis L.) lines and to estimate the parameters for fenotypical adaptability and stability. The evaluations for period 1 were conducted between November, 2006 to June, 2007, and period 2, consisted of March to August, 2005 in Araçatuba, Botucatu, Ilha Solteira, São Manuel and Penápolis, Municipals Districts, in São Paulo State, by using randomized complete blocks scheme with three replicates and useful plots of 10 m2. Individual variance analysis for each site were calculated as well as joint variance analysis involving the five locations for each period and subsequently averages were compared by Scott and Knott test (1974) to 5% of probability. Significance was observed for the characteristic evaluated in all analysis and due to the significant interaction between periods, locations and lines, data were studied with analysis of fenotypical adaptability and stability considering the environment as the sowing crop periods according to the methodology proposed by Finlay and Wilkinson (1963). For period 1, in relation to grains yield, lines 1, 6, 8, 15, 16, 18 were outstanding. For adaptability and stability fenotypical parameters, lines 3, 13 and 18 showed general adaptability and medium stability. In period 2, compared with the same parameters, lines 1, 2, - 3 - 4, 7, 10, 11, 12, 14, 15, 16, and 19 presented higher grains yield, predominance of specific adaptability to favorable environments and inferior stability. For the two sowing crop periods, lines 1, 6, 8, 15 and 16 were superior in grains yield. / Doutor

Thesis topic: Assessment of wheat yield and quality. Three conventional varieties (Midas, Genius and Papageno) and one hybrid variety (Hyland) were subject to the test. The test was carried out in operational conditions of an agricultural plant in 2014. The assessed Midas and Genius varieties are classified as elite varieties in terms of baking quality and the Papageno variety and the hybrid Hyland variety are classified as unsuitable for dough production. The test was aimed at the assessment of the main yield elements, i.e. the number of spikes per m2, the number of grains per spike and the weight of a thousand grains. Another assessment parameter was the quality of grains of the assessed varieties.