Popcorn was popped conventionally in oil and in a microwave oven without oil. Volatile components were collected by condensation of popper headspace gases and by vacuum steam distillation of a slurry of ground, popped corn in distilled water. The organic compounds were extracted from the aqueous condensate and vacuum distillate with diethyl ether. The concentrated ether extracts were analyzed by a coupled gas chromatograph-mass spectrometer utilizing three different procedures. These were: (1) a 300 foot by 0.01 inch ID capillary column, into which samples were injected with a 50:1 inlet split, with the effluent end connected directly to the ion source of the mass spectrometer; (2) the same directly coupled capillary column but with samples previously trapped from a packed column introduced without splitting; (3) mass spectrometric analysis of a portion (5 to 10%) of the effluent stream from a 12 foot by 1/8 inch OD packed column. Thirty-six compounds were positively identified by comparison of their spectra with reference spectra. Relative retention time coincidence with known compounds confirmed the mass spectral identifications. Those compounds positively identified include pyrazine, 2, 5-dimethyl pyrazine, 2, 3-dimethyl pyrazine, 2-ethyl-5- methyl pyrazine, 2-ethyl-3, 6-dimethyl pyrazine, 2-pentyl furan, furfural, 2-acetyl furan, 5-methyl furfural, furfuryl alcohol, 5-hydroxymethyl furfural, acetaldehyde, 2-methyl propanal, 5-methyl butanal, pentanal, hexanal, benzaldehyde, phenylacetaldehyde, diacetyl, ethyl acetate, methyl palmitate, diethylphthalate, ethanol, hexane, acetic acid, hexanoic acid, palmitic acid, γ-kutyrolactone, N-furfuryl pyrrole, N-furfuryl pyrrole-2-aldehyde, 2-acetyl pyrrole, pyrrole-2-aldehyde, 4-vinyl-2-methoxyphenol, 4-vinylphenol, and vanillin. Another 20 compounds were tentatively identified on the basis of their mass spectra. These were 2, 3, 5-trimethyl pyrazine, 2-acetyl pyrazine, (5-methyl-2-furyl)-(2 furyl)-methane, 5-methyl- 2-acetyl furan, bi-(5-methyl-2-furyl)-methane, 4-hydroxy-2, 5-dimethyl-3 (2H)-furanone, heptanal, ethyl formate, pyridine, thiazole, benzothiazole, ethylbenzene, a dichlorobenzene, N-ethylpyrrole- 2-aldehyde, N-isoamyl-pyrrole-2-aldehyde, 5-methylpyrrole- 2-aldehyde, 2-formyl-5-methylthiophene, 2-ethyl-5-butylthiophene, phenol, and 2-methoxyphenol. It is believed that pyrazines, furans, carbonyls, and phenolic compounds make important contributions to the flavor and aroma of popcorn. The presence of many of the compounds identified can be explained by their production during popping from precursors in the popcorn kernels by Maillard browning reactions, Strecker degradation of amino acids, thermal oxidation and hydrolysis of lipids, and direct thermal degradation of plant constituents. / Graduation date: 1969

Compared with our leading crops pop corn is of minor importance from the standpoints of both world and domestic product ion. However, it holds an important place in many states, especially in certain localities. The census report gives the acreage of pop corn in 1909 for the eleven leading pop corn producing states, namely, Iowa, Nebraska, Illinois, Kansas, Ohio, Michigan, California, Indiana, Hew York, Minnesota, and Wisconsin as 11,343 acres; valued at #285,286. Although the average farm usually grows a small acreage as high as 1000 acres is reported as being grown by one Iowa producer.

Popcorn is the most popular snack food in the world. Genetic diversity is of major concern in popcorn breeding. High genetic diversity allows manipulation of different genotypes to breed new varieties. There is very little published work on popcorn production in Sub-Saharan Africa primarily in South Africa. Popcorn production in South Africa could be hampered by the lack of superior and adapted varieties with large genetic base, good popping ability and high yield. Studies relating popping expansion volume and grain yield are of fundamental importance for popcorn improvement, but they are limited. Furthermore, there is limited number of studies regarding popcorn genetic diversity among locally developed popcorn varieties. The objectives of the study were; (i) to investigate genetic variability among the popcorn inbred lines, (ii) to study the magnitude of genetic diversity among the popcorn inbred lines, (iii) to establish the relationship between popping ability and seed yield, and with secondary traits, and (iv) to evaluate the effect of popping methods on popping ability of different popcorn inbred lines. Two populations designated as Population 1 and Population 2 with 83 and 81 inbred lines, respectively, were used in the study.On the study of the appraisal of popping methods, the highest popping expansion volume (cm³) and less number of unpopped kernels were obtained from hot air popping than in the microwave popping method. The study revealed that hot air popping method is more effective and efficient in discriminating popping ability of the inbred lines. The study further revealed that the two methods rank genotypes differently. The presence of genotype × popping method interaction resulted in three different groups. (i) Genotype adaptation across methods, (ii) specific adaptation to microwave popping, and (iii) specific adaptation to hot air popping method. Hence, when breeders evaluate popping ability of different genotypes, they should consider the method, depending on the way consumers will do the popping. The study of relationship between traits showed that popping expansion volume and seed yield was positively and significantly correlated. Nevertheless, the relationship between seed yield and popping expansion volume was weak. Popping expansion volume was negatively and weakly correlated with most secondary traits except kernel aspect and number of unpopped kernels. The direct effects of kernel aspect score on popping expansion volume were large and negative. Other traits showed small direct and indirect effects on popping expansion volume. Traits including days to anthesis, ear prolificacy and ear aspect exhibited large direct effects on seed yield. Indirect and direct effects of other traits on seed yield were small. Relationship among several secondary traits was small. The results obtained showed that selection for high seed yield will not negatively impact popping expansion volume and vice versa, therefore, popping expansion volume and seed yield can be improved concurrently. Overall, indirect effects of secondary traits on seed yield and popping expansion volume were small; this supported the focus on direct selection of these traits to improve seed yield and popping ability. Based on the study of genetic diversity and variability, inbred lines showed large genetic variation and high heritability for 18 traits. Phenotypic and genetic coefficient of variation was high in seven and six traits, respectively. A large percentage of genetic advance was recorded in 11 traits. Dendogram derived from phenotypic data grouped the inbred lines into four to seven clusters depending on heritability. Dendogram produced from 22 SSR markers grouped inbred lines into five clusters. Overall, the study showed that, maximum popping ability of inbred lines is dependent on the method used. Simultaneous improvement of seed yield and popping expansion volume is possible through selection of inbred lines combining both high popping expansion volume and seed yield. Improvement of the two traits should be based on selection for traits with large direct effects. The magnitude of genetic diversity among the inbred lines was large; therefore, distant inbred lines can be selected as parents and crossed to develop new varieties that are locally adapted. Above all, the results have implications for the methods which would be used to process popcorn by consumers especially in developing rural communities. / Thesis (M.Sc.Agric.)-University of KwaZulu-Natal, Pietermaritzburg, 2012.

Popcorn is increasingly becoming popular as a snack and is consumed widely all over the world. It is a high value crop, with possible multiplier effects like income generation for the under-resourced communities in the second economy. Despite its popularity, developing countries are battling to meet the demand and rely on importing popcorn grain due to challenges which include poor agronomic traits and slow breeding progress. Most of the imported varieties are not adapted to stress-prone local environments, which are prevalent in tropical sub-Saharan Africa. The objective of the study was to evaluate newly developed hybrids and inbred lines for agronomic and popping quality traits with the possibility for commercialization in future. The study aimed at determining variability for popping ability in inbred lines and hybrids, grain yield and its secondary traits, the nature of gene action, relationships among agronomic and popping quality traits, effect of genotype x environment interaction on agronomic traits and popping method x genotype interaction effects. To determine popping ability, 128 inbred lines were evaluated at the University of KwaZulu-Natal, South Africa, in June 2011 using two popping methods, the microwave method and the hot-air method. The popping quality attributes measured were flake volume, popping fold, number of unpopped kernels, kernel size and quality score. Variability among inbred lines was significant (P<0.05) for all traits. Flake volume ranged from 63 cm3 to 850 cm3, popping fold ranged from 2.5 to 34 times the original volume. Kernel size had a significant positive correlation (r= 0.49) with the number of unpopped kernels. There was a significant strong and negative correlation between flake volume and the number of unpopped kernels (r= -0.62), indicating that either of the two traits would be effective for measuring popping ability. Experimental hybrids were then developed from 87 out of the possible 128 inbred lines. Only the inbred lines with sufficient seed were crossed to develop hybrids. Random crosses were generated at Makhathini Research Station during the winter season of 2011. Crosses were made at random among parents that managed to synchronize their flowering dates, resulting in 119 hybrids with sufficient seed for planting in trials. To determine agronomic superiority, the 119 experimental hybrids and the standard check P618 were evaluated at the Cedara Research Station and Ukulinga Research Farm in the Midlands of KwaZulu-Natal during the summer of 2011/2012. The experiments were laid out as 10 x 12 alpha lattice design, with two replications at each site. Standard cultural practices for maize were followed. The data were subjected to analysis of variance and line x tester analysis in Genstat and SAS statistical programmes. Results indicated that hybrids were significantly different for all agronomic traits. Means for grain yield ranged from 1.0 t/ha to 5.2 t/ ha. General combining ability effects were significant for all agronomic traits, suggesting that additive gene effects were governing these traits. Specific combining ability effects were significant for ear length, number of ears per plant and yield indicating, that non-additive gene effects were influential for these traits. Generally, agronomic traits were highly heritable. Grain yield showed significant and positive correlation with ear length, plant height, ear position, shelling percentage and number of ears per plant, indicating that these were the major yield-determining secondary traits which should be enhanced in popcorn. Although site main effects were highly significant for secondary traits, the hybrid x site interaction was not significant. The results therefore indicate that the hybrids were ranked similarly at both sites. The 119 experimental hybrids and the standard check P618 were evaluated for popping quality, using the microwave and the hot-air popping method. There was a significant variability observed among hybrids for popping quality traits. Flake volume across sites and across popping methods ranged from 734 cm3 to 1288 cm3. Popping fold ranged from 14.69 to 25.75 times the original volume. Additive gene action was more prominent than non-additive action for all popping quality traits. The SCA effects were significant for flake volume, popping fold and number of kernels per 10 g. All popping quality traits had high heritability, indicating that selection would be effective to improve popping. Flake volume was negatively correlated to quality score, indicating that popping expansion is reflected on the quality score and a significant negative correlation between flake volume and number of unpopped kernels. There was significant and strong positive correlation between kernel size and number of unpopped kernels. Hybrid x site interaction was only significant for quality score and kernel size. Hybrid x method interaction was not significant, indicating that popping ability was not dependent on the method. Inbred lines showed significant variation for popping quality and therefore have utility for hybrid development. Significant genotypic variation was also observed among hybrids for agronomic and popping quality traits. Additive gene action was predominantly responsible for both agronomic and popping quality traits. Both agronomic and popping quality traits were highly heritable and positive relationships were identified among traits. Overall, the study indicates opportunities for further breeding progress through selection. / Thesis (M.Sc.)-Unversity of KwaZulu-Natal, Pietermaritzburg, 2012

Thesis (doctoral)--Ludwig-Maximilians-Universität München, 2000. / Title from PDF t.p. (viewed on May 14, 2006). Vita. Includes bibliographical references (p. 225-230).

Seed dispersal is a crucial ecological and evolutionary process that allows plants to colonize sites and expand their ranges, while also reducing inbreeding depression and facilitating the spread of adaptive genetic variation. However, our fundamental understanding of seed dispersal is limited due to the difficulty of directly observing dispersal events. In recent years, genetic marker methods have furthered our understanding of colonization and range expansion due to seed dispersal. Most investigations focus on regional scales of dispersal, due to low levels of variation in the chloroplast genome (cpDNA), which can serve as an indirect measure of seed dispersal. Here, I employ a whole-genome assay of cpDNA variation in Plagiobothrys nothofulvus to resolve variation due to patterns of seed dispersal within a 400x400 meter section of the Whetstone Savanna Preserve in Central Point, OR, USA. Whetstone is characterized by a mosaic of habitat types, including vernal pools, hummocks of dry prairie, and large Ceanothus cuneatus bushes, as well as a network of vole runways. Plagiobothrys nothofulvus grows in dense patches on hummocks within this prairie. I found evidence of limited seed dispersal in P. nothofulvus, indicated by strong genetic structure over distances of less than 100 meters. There was little evidence that geographic distance predicts genetic distance; environmental features have a stronger influence on dispersal. Habitat preference was the strongest predictor of genetic variation in P. nothofulvus, indicating that it may be a habitat specialist in this prairie. Flower density also accounted for a significant portion of dispersal, which may be a consequence of the annual life history of P. nothofulvus resulting in seasonal turnover and lack of competition with adult plants. Least-cost-path analysis indicated that seeds are secondarily dispersed by small mammals along vole runways. Overall, I found significant evidence that landscape features influence dispersal, even at a very fine spatial scale.

In the packaging industry, cushioning products are usually made of plastic materials, such as polystyrene. The insulation and lightweight character make it more popular and convenient to use. However, the extensive use of it creates more waste leading to an environmental problem. Usually the cushioning foams are discarded after being used for inbox protection as packaging material; eventually they end up in a landfill. Most plastic foams are not biodegradable, which cannot be composted and will create more and more waste that affects the ecological system. In the mean time, foams made up of bio-degradable materials are considered. In general, biodegradable plastics are starch-based or cellulose-based, and the biodegradable components can be found in corn (e.g. corn starch, and corn cob). Instead of extracting the corn component, here popped corn kernel will be investigated for its suitability in packaging applications.

No description available.

Maize (Zea mays L.) is one of the most important food crops in sub-Saharan Africa (SSA); however its production is constrained by many factors. Grain yield is compromised by poor genetic performance and poor agronomic management. This calls for need to develop hybrids and exploiting heterosis of single crosses which are adapted to challenging environments. Currently, there is no popcorn hybrids developed in South Africa which is adapted to local conditions. As such, there is need to develop hybrids that cater for smallscale farmers in marginal environments. The objectives of the study were to determine i) standard heterosis, levels of variation and heritability for phenotypic traits in dent and flint maize hybrids; ii) the association between genetic distances and phenotypic traits in dent and flint maize hybrids; iii) mid-parent heterosis in popcorn hybrids, iv) the effect of secondary traits on grain yield in dent, flint and popcorn hybrids; v) genetic diversity and the relationship between traits in widely grown selected hybrids in Southern Africa; and vii) to compare effectiveness of phenotypic analysis models for determining genetic distances between hybrids. Popcorn, dent and flint hybrids were evaluated at two sites. The data was analysed using SAS, Genstat and Power marker statistical packages. The results revealed that the relationship between genetic distance and heterosis is dependent on the environment. Hybrids in top 10 at both sites were different indicating that there was a significant genotype x environment interaction. 13 new heterotic patterns that performed better than the controls can be utilized in heterosis breeding; however there is need to test them in different environments to check on their stability. Grain texture cannot be used to discriminate hybrids for yield because all patterns of dent x dent, dent x flint and flint x flint were present in the top 10 hybrids. Lines DXL124 and DXL158 dominated parentage of the top 10 hybrid rank for yield qualifying them as potential testers for specific combining ability in future studies. Heterosis in popcorn hybrids that performed better than the mid-parent can be utilized in heterosis breeding to exploit vigour, though there is need to test the hybrids in a number of different environments. The main direct factors contributing to yield were ear prolificacy, ear aspect, number of plants and shelling percentages qualifying them to be selected to boost grain yield. Phenotypic data and 91 SNP markers were used to estimate the genetic distance between the hybrids. The results indicated that hybrids that were in the same cluster belong to the same brand and were related in origin and pedigree. Both molecular and phenotypic data were effective in discriminating the hybrids into different clusters according to genetic background. SNP markers revealed nine clusters of hybrids, 12-trait model revealed eight clusters and five-trait model revealed six clusters at 85% genetic distance. The study indicates strategies that can be adopted to boost grain yield in dent, flint and popcorn hybrids. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2013.

Master of Science / Department of Grain Science and Industry / Subramanyam Bhadriraju / Spinosad, methoprene, deltamethrin, and deltamethrin plus methoprene, are approved in the United States for treating popcorn. The Indian meal moth, Plodia interpunctella (Hübner), and maize weevil, Sitophilus zeamais (Motschulsky) are two stored-product insects found in popcorn. The efficacy of spinosad and methoprene against P. interpunctella in popcorn were determined in laboratory and field studies. In the laboratory study, eggs (to represent first instars), third, and fifth instars of the laboratory strain of P. interpunctella were exposed to 0.7, 1.4, 2.8 ppm methoprene and 1 ppm spinosad treated popcorn, respectively, to assess larval or adult emergence. In the field study, untreated and treated popcorn samples were placed in vinyl mesh pouches with two mesh-opening sizes and were buried 5 cm below popcorn surface. Pouches with large mesh-opening were used to monitor natural insect infestation between May to October, 2017. Pouches with small mesh-opening were used to conduct laboratory bioassays to evaluate adult emergence of P. interpunctella from eggs after exposed to treated popcorn. Probe traps, food- and pheromone-baited traps, and sticky traps were used to monitor insects in storage bins and cleaning processing facility. The laboratory study showed that there was no P. interpunctella adults emerged from eggs, third, and fifth instars in methoprene treated popcorn during 6 month storage. However, methoprene did not reduce egg-to-larval survival. Larval and adult emergence in the spinosad treated popcorn was significantly lower than controls. Field study showed that there was no adult emergence in methoprene treated popcorn in most cases, and significantly lower adult emergence in spinosad treated popcorn compare to control. P. interpunctella larva was the major insect found in large pouches. The red flour beetle, Tribolium castaneum (Herbst), and P. interpunctella were primary insect species captured by probe traps, food- and pheromone-baited traps and sticky traps over the six months’ study. These results suggested that methoprene could reduce P. interpunctella adult emergence. Spinosad also effectively suppressed the infestation of P. interpunctella. The field strain of S. zeamais was exposed to spinosad (1 ppm), methoprene (0.7, 1.4, 2.8 ppm), deltamethrin (0.5, 1.0 ppm), and deltamethrin plus methoprene (0.5+1.25, 1.0+2.5 ppm) treated popcorn, respectively, for 1 to 336 h exposure time. Mortality was assessed at 0, 7, 14, and 21 d after transferring to clean popcorn except for methoprene treatments which only counted mortality at 0 d. Progeny and adult emergence were counted after 42 d incubation in clean or original popcorn, respectively. All insecticides showed no delay toxicity against S. zeamais adults. Spinosad caused 100% mortality of S. zeamais after 336-h exposure. Complete progeny reduction and highest adult emergence reduction at 168 h exposure. The highest mortality of S. zeamais was 67.1 and 70.5% in deltamethrin and deltamethrin plus methoprene treated popcorn, respectively. Methoprene showed limited efficacy against S. zeamais including low mortality, progeny reduction and high adult emergence. These results indicated that spinosad was effective against S. zeamais. It is necessary to combine other insecticides with deltamethrin and methoprene to control field strain of S. zeamais in stored popcorn.