Sorghum breeders have not made much yield improvement in new sorghum varieties in Kenya since Serena in was released in the late 1960s. KARI Mtama-1 which was released in 1993 has no yield advantage over Serena. A yield plateau for sorghum in Kenya is apparent. A new breeding approach was adopted to break that yield barrier. Development of hybrid sorghum was proposed and is expected to break the yield barrier and also deliver cultivars that meet farmers' main requirements. The objectives of the study were to (1) identify farmers' requirements in sorghum cultivars, constraints to sorghum production and why improved cultivars from research are not being adopted, (2) characterize male and female parents and establish if genetic distance could identify superior parent populations for hybrid production (3) estimate genetic variance components and determine the possibility of using GCA and SCA estimates in choosing parents for use in hybrid production, (4) test hybrids and open pollinated variety (OPV) parental lines for stress tolerance and identify tolerant hybrids for further testing and, (5) compare single cross hybrids and OPV varieties in yield performance. Participatory rural appraisal in Kitengei and Nzambani areas of Kambu showed that sorghum was especially important in semi-arid parts of Kenya. Food, trade, feed, nursing food and thatching were the most important uses of sorghum. High grain and stover yield, large grain size, early maturity, drought tolerance, pest and disease resistance, coloured grain and intermediate plant height were the major requirements of farmers. Fifty-three pollinators and forty-one male sterile parents were introduced from four sources and screened together with 27 pollen parents from Kenya. Parents and hybrids were tested in 4 environments: high and low plant density, in high and low moisture regimes laid out in a triple square lattice design in Kenya, with parents having two additional tests in South Africa. Males, females, sexes and parental sources differed significantly in head weight. There were sex x country and sex x environment interactions for head weight. Genetically distant parents' populations had higher chances of superior heterosis. Parents showed significant additive genetic variance in head weight. The regression of non-additive to additive genetic variance was roughly one and significant. Three female and five male parents were suitable for production of hybrids adapted to multiple environments. Hybrids and OPV lines significantly varied in head weight. Hybrids were superior to OPV lines in most agronomic traits. Economic superiority of the hybrids was sufficient to cover cost of hybrid production and distribution in Kenya. Hybrids and OPV lines varied significantly for plant density stress. Hybrids were less sensitive to stress and more productive than OPV lines under population density stress. KARI varieties were sensitive to plant density stress. In general low sensitivity to stress was beneficial and hybrids had superior yield to inbred varieties. / Thesis (Ph.D.)-University of KwaZulu-Natal, Pietermaritzburg, 2006.

Master of Science / Food Science Institute / Edgar Chambers IV / Sorghum (Sorghum bicolor [L.] Moench), is an ancient grain that possesses many health and economic values. Understanding the differences in the flavor profiles among cultivars is essential to increase the usage of the grain for food application purposes. The main objectives of this study were to 1) develop a model system to taste grain varieties and 2) develop a sensory lexicon to describe the flavor profile of sorghum grains. Fifty-seven sorghum cultivars including US commercially available samples as well as important breeding lines from around the world were included and investigated in the study. After thorough investigations, this study developed a model which includes cooked grain and cookie applications to facilitate flavor characterization among different cultivars. The cooked grain and cookie recipes developed in this project are neutral and consistent. Therefore, they can serve as systems prototypes for identification of a grain’s flavor profile and support descriptive analysis studies of flavor among grain cultivars. The developed model has been applied in sorghum and wheat to successfully characterize the flavor profile among different cultivars. Moreover, a sensory lexicon with 28 descriptive terms was developed by the trained panel to describe the flavor of sorghum in grain form and in finished products. Some of the terms in the lexicon were starchy, beany, cardboard, oil-heated, brown-sweet, buttery, umami, overall green, musty dusty, woody, wheat like, sweet, salty, sour, bitter and metallic. Each attribute has a descriptive definition to describe the term and two to three descriptive references. The panel validated the effectiveness of the developed lexicon using a set of 20 sorghum cultivars, which were presented to the panelists in two forms: cookies and cooked grains. The descriptive analysis results were analyzed using PCA to produce sensory maps with key attributes associated with each sample. The generated maps for both cooked grain and cookies application showed clear differentiation in flavors among sorghum cultivars indicating that the lexicon can be used to effectively characterize sorghum’s flavors in multiple applications. Such understanding will help to support researchers, food producers, food manufacturers and contribute to promoting the use of sorghum grains in food applications.

Grain sorghum is a drought tolerant crop used in the Mid-south region in rotation with corn, cotton, soybeans, and corn. In 2015 and 2016, research was conducted to determine the influence of insecticide treatment, planting date, planting population, hybrid, and environmental temperatures on sugarcane aphid, Melanaphis sacchari (Zehntner), populations and yield in grain sorghum, Sorghum bicolor (L.) Moench. In general, cooler temperatures had a negative effect on sugarcane aphid control with sulfoxaflor and flupyradifurone. Additionally, there was a negative relationship between grain sorghum plant population and sugarcane aphid densities per plant. These data suggest management of sugarcane aphid with insecticide seed treatments and foliar sprays is critical for maximizing grain sorghum yields. Additionally, growers should wait for warmer temperatures to ensure optimum control.

No description available.

Sulphur (S) is an essential element for plant and animal nutrition, but widespread deficiencies of S occur world wide. Current recommendations for nitrogen (N):S ratios are 15 to 18:1 and 10 to 12:1 for plant and animal nutrition, respectively; but recent information suggests these may not predict animal response. Sorghum is an important crop, particularly in drier climatic regions but little is known concerning S-nutrition for sorghum growth or utilization of S-fertilized forages. Sorghum "Pioneer 947" was grown on a Lucy loamy sand (loamy, siliceous, thermic Arenic Kandiudult) in King William County, VA, with and without S fertilization (0 vs. 138 kg S ha⁻¹ as ammonium sulphate) in a randomized block design with four replications. Sulphur fertilization decreased (P < 0.05) soil pH and increased soil S in the 0 to 25 cm (P < 0.08) and 25 to 50 cm (P < 0.05) soil layers. An increase in Mehlich-I extractable soil P, Mn (P < 0.05) and soil N0₃-N (P < 0.06) at surface 25 cm layer occurred with S-fertilization. At harvest, S-fertilization increased (P < 0.05) S and water soluble carbohydrates and decreased (P < 0.05) N:S ratio and P concentration in whole plants. Sorghum leaves were higher (P < 0.05) in N, S, Ca, Mn and Cu in S fertilized compared to non-S fertilized sorghum. Sulphur fertilization decreased (P < 0.05) concentration of hydrocyanic acid (HCN) in the upper three leaves. A greenhouse experiment was conducted with the Lucy soil and 'Pioneer 947' sorghum to further investigate effects of fertilization (0, 70, and 140 kg S ha ⁻¹) as ammonium sulphate in a completely randomized design with five replications. Sulphur application decreased soil pH, and extractable soil K linearly (P < 0.01), and increased extractable soil S linearly (P < 0.01). / Ph. D.

Several crops are being touted as a renewable energy source. Sweet sorghum is adapted to many areas, grows relatively rapidly, has moderate water and nutrient requirements, and develops high levels of fermentables. A long term supply of fermentables is needed to make ethanol production economically feasible. Short term availability of fermentables results in unfavorable returns from investments in equipment and crop production. Two planting dates (15 May and 1 June) and eight harvest dates (30 Sep. to 15 Mar.) were used in efforts to to extend the availability of sweet sorghum fermentables. Respiration of sweet sorghum tissue was measured with an infrared gas analyzer before and after freezing to quantify loss of fermentables associated with delayed harvests. Vital stains were used before and after freezing to estimate cell mortality. No significant difference was found in the level of fermentables in sorghum from the two planting dates. Delay-ing harvest caused fermentables to decline significantly (30%) by mid-November and to continue to drop through March. Respiration dropped 90% after exposure to -8 C, but resumed the same rate after 1 week. Vital stai!1ing showed cells die upon freezing. Relatively high respiration rates in the dead tissue suggests saprophytic microbes are responsible for the large decline in fermentables after freezing. Eleven cultivars and lines were tested for yield of fermentables. Wray was superior in yield of fermentables, while Sumac and Sugardrip were inferior. / Master of Science

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Call number: LD2668 .T4 1955 P75 / Master of Science

Call number: LD2668 .T4 1956 W36 / Master of Science