The mollicutes corn stunt spiroplasma (CSS; Spiroplasma kunkelii) and maize bushy stunt phytoplasma (MBSP) infect maize phloem tissue and disturb its physiology and kernel production. These pathogens are disseminated by the leafhopper Dalbulus maidis and cause severe corn stunting accompanied by drastic decrease in kernel production. The effects of these diseases on kernel production, nutrition and water retention of different tissues of several maize cultivars were evaluated. The experiment was carried out in a factorial design consisting of 3 inoculation treatments (healthy plants, phytoplasma-infected plants and spiroplasma-infected plants) and 6 cultivars of maize (Zea mays L.). Plants infected with mollicutes sustained reduced plant height and kernel production, however the magnitude of these effects varied among cultivars and was generally greater for spiroplasma-infected plants than for phytoplasma-infected plants. Mollicute infections reduced the overall in plant concentration of Mg and amounts of nutrients (K, Mg, P, N, Ca and Zn) taken up by plants tissues. These effects were variable for different maize cultivars. However, mollicute infection did not affect the nutrient concentrations in the kernels. At 100 days after planting, ratios of water to dry matter were similar among healthy plants, but were highly variable among CSS- and MBSP-infected cultivars, the latter two groups retaining on average 15% to 40% more water than healthy cultivars. The water potential values of diseased plants were variable, but were not clearly distinct among healthy and diseased plants | [Il corn stunt spiroplasma (CSS; Spyroplasma kunkelii) e il maize bushy stunt phytoplasma (MBSP), appartenenti alla classe Mollicutes, infettano il floema del mais e alterano la sua fisiologia e la produzione di cariossidi. Questi patogeni sono diffusi dalla cicalina Dalbulus maidis e causano una crescita molto stentata e una drastica diminuzione della produzione di cariossidi. Sono stati valutati gli effetti di queste malattie sulla produzione di cariossidi, la nutrizione e la ritenzione dell'acqua di tessuti diversi di numerose cultivar di mais. L'esperimento è stato condotto secondo uno schema sperimentale fattoriale consistente in 3 trattamenti di inoculazione (piante sane, piante infettate dai fitoplasmi e piante infettate dagli spiroplasmi) e 6 cultivar di mais (Zea mays L.). Le piante infettate con i Mollicutes subivano una riduzione di altezza e di produzione di cariossidi, tuttavia l'entità di questi effetti variava fra le cultivar ed era generalmente maggiore per le piante infettate dagli spiroplasmi rispetto a quelle infettate dai fitoplasmi. Le infezioni hanno ridotto la concentrazione complessiva di Mg nella pianta e la quantità di elementi nutritivi (K, Mg, P, N, Ca e Zn) assimilati dai tessuti delle piante. Questi effetti sono risultati variabili per le diverse cultivar. Tuttavia, l'infezione non ha influenzato la concentrazione di elementi nutritivi nelle cariossidi. A 100 giorni dalla semina, i rapporti fra acqua e sostanza secca erano simili nelle piante infettate, ma altamente variabili nell'ambito delle diverse cultivar infettate da CSS ed MBSP; gli ultimi due gruppi ritenevano in media il 15% e il 40% in più di acqua rispetto alle cultivar sane. I valori del potenziale dell'acqua delle piante ammalate erano variabili, ma non chiaramente differenziati fra piante sane e ammalate.]

This experiments were carried out to determine growth characteristics, dry matter yield and voluntary intake of silage according to growth stage of Sorghum × sudangrass(SSH) hybrid in mono-cropping and inter-cropping(C; com, T1; cutting of SSH at milk stage, T2; cutting of SSH at dough stage, T3; cutting of SSH at yellow ripe stage, T4; cutting of SSH and soybean at milk stage, T5; cutting of SSH and soybean at dough stage, T6: cutting of SSH and soybean at yellow ripe stage). Results obtained from these experiments are as follows; Plant length and leaf length of SSH(T2, T3, T4, T5 and T6)) were higher than C, T1 treatment was lower than it. C showed 2.3~2.9 times higher stem diameter as 29.5mm compare to SSH(T1, T2, T3, T4, T5 and T6), soybean(T4, T5 and T6) was lower in 4.3~5.4 times.

Thirty six maize (Zea mays L.) hybrids along with their parental lines were grown in a randomized complete block design with two replications to assess the genetic correlation among 16 quantitative traits. A positive genetic correlation with grain yield was recorded for plant and ear heights, leaves plant-1, leaf length, width and area, ear weight and kernels row-1. Days to silking and tasselling, and grain moisture at harvest were negatively and correlated with grain yield, while ears plant-1, grain moisture at harvest, kernel rows ear-1 and 100-kernel weight exhibited positive but no genetic correlation existed with grain yield. Kernels row-1 was marked as the most contributing character towards high grain yield (rA = 0.76) followed by leaf area (rA = 0.69), plant height (rA = 0.67) and leaves plant-1 (rA = 0.43). A strong positive genetic correlation was observed among plant height, leaf area, leaves plant-1, ear weight, kernels row-1, and grain yield indicating that selection for these characters can help improve maize grain yield.

Feasibility study of growing naturally colored cotton, Gossypium hirsutum, PM1and PM4 and Gossypium arboreum, PM2 along with white cotton, G.arboreum, PM3 comparing with the standard white G.hirsutum, SR60 was conducted from 2003-2004 at the National Corn and Sorghum Research Center, Pak Chong, Nakhon Ratchasima. RCB was used with 4 replicates, each with 5 rows of each variety. Data of insects were biweekly collected in the three middle rows for four consecutive times. In both years, the kinds and mean numbers of key pest were mainly leafhopper, Amrasca biguttula, and the plant bug, Megacoelum biseratense while the bollworm, Helicoverpa armigera was found in 2004 only. The 2003 and 2004 similar results revealed that the leafhoppers on PM1 and SR60 and those on PM2 and PM3 were not significantly different while all were significantly different from PM4. The average amounts of plant bug on every variety in both years were also found not to be significantly different from one another. Comparing the numbers of leafhopper between 2003 and 2004, they were significantly different at all varieties except PM2, while those of the plant bug on every variety did not significantly differ. As for the fiber analysis and percent gin turn out, PM1 was found to have the acceptable qualities compared with the standard ranges of fiber determination as well as the commercial variety, SR 60.

Sorghum [Sorghum bicolor (L.) Moench] breeders have long recognized the importance of exotic germplasm and noncultivated sorghum races as sources of valuable genes for genetic improvement. The genus Sorghum consists of 25 species classified as five sections: Eu-sorghum, Chaetosorghum, Heterosorghum, Para-sorghum, and Stiposorghum Species outside the Eu-sorghum section are sources of important genes for sorghum improvement, including those for insect and disease resistance, but these have not been used because of the failure of these species to cross with sorghum. An understanding of the biological nature of the incompatibility system(s) that prevent hybridization and/or seed development is necessary for the successful hybridization and introgression between sorghum and divergent Sorghum species. The objectives of this study were to determine the reason(s) for reproductive isolation between Sorghum species. The current study utilized 14 alien Sorghum species and established that pollen–pistil incompatibilities are the primary reasons that hybrids with sorghum are not obtained. The alien pollen tubes showed major inhibition of growth in sorghum pistils and seldom grew beyond the stigma. Pollen tubes of only three species grew into the ovary of sorghum. Fertilization and subsequent embryo development were not common. Seeds with developing embryos aborted before maturation, apparently because of breakdown of the endosperm.

Sorghum [Sorghum bicolor (L.) Moench] breeders have long recognized the importance of exotic germplasm and noncultivated sorghum races as sources of valuable genes for genetic improvement. The genus Sorghum consists of 25 species classified as five sections: Eu-sorghum, Chaetosorghum, Heterosorghum, Para-sorghum, and Stiposorghum Species outside the Eu-sorghum section are sources of important genes for sorghum improvement, including those for insect and disease resistance, but these have not been used because of the failure of these species to cross with sorghum. An understanding of the biological nature of the incompatibility system(s) that prevent hybridization and/or seed development is necessary for the successful hybridization and introgression between sorghum and divergent Sorghum species. The objectives of this study were to determine the reason(s) for reproductive isolation between Sorghum species. The current study utilized 14 alien Sorghum species and established that pollen–pistil incompatibilities are the primary reasons that hybrids with sorghum are not obtained. The alien pollen tubes showed major inhibition of growth in sorghum pistils and seldom grew beyond the stigma. Pollen tubes of only three species grew into the ovary of sorghum. Fertilization and subsequent embryo development were not common. Seeds with developing embryos aborted before maturation, apparently because of breakdown of the endosperm.

Sweet sorghum Sorghum bicolor (L.) Moench is a special purpose sorghum with a sugar-rich stalk, almost like sugarcane. Besides having rapid growth, high sugar accumulation, and biomass production potential, sweet sorghum has wider adaptability (Reddy and Sanjana 2003). Given that water availability is poised to become a major constraint to agricultural production in coming years (Ryan and Spencer 2001), cultivation of sugarcane becomes difficult. Sweet sorghum would be a logical crop option in lieu of sugarcane in such situations. Sweet sorghum can be grown with less irrigation and rainfall and purchased inputs compared to sugarcane. The sugar content in the juice extracted from sweet sorghum varies from 1623% Brix. It has a great potential for jaggery, syrup and most importantly fuel alcohol production (Ratnavathi et al. 2004a). The stillage after extraction of juice from sweet sorghum can be used for co-generation of power.

Thesis (PhD (Food Science))--University of Pretoria, 2005. | The possibililty of using the simple technologies of malting and fermentation to modify endogenously the sorghum grain components, to alleviate the grittiness, dryness and high crumb firmness caused by the inclusion of sorghum flour in composite bread, was investigated. The most suitable grain and the optimal malting time for sorghum for bread¬making, were selected by malting five sorghum cultivars, up to 8 days, and evaluating them for the highest protein modification and lowest dry matter losses. On that basis, a 6¬days malt of Local White, a relatively high protein sorghum (10.7%), was selected. Sorghum malt flour potentially suitable for bread-making was produced by boiling the selected malt, rather than drying it at high temperatures, stewing or steaming. Boiling was most effective in inactivating the amylases and in increasing the pasting viscosity of sorghum malt. The bread made with boiled malt flour (30%) had an improved crumb structure and water-holding capacity, a softer crumb and increased resistance to staling, compared to bread made with sorghum grain flour (30%). Bread-making with reconstituted flours from flour and bran fractions of whole sorghum grain and whole boiled sorghum malt indicated that the bread improving effect of malting and boiling was due to dextrinization and gelatinization of starch, and to the increase of total and water-soluble pentosans, and crude fiber. Dextrinization and gelatinization of starch decreased the gelatinization temperature and the rate of starch retrogradation, thus decreasing the crumb firmness and firming rate of sorghum and wheat composite bread. However, high levels of gelatinized starch decreased dough strength and bread volume. The increase of total pentosans and crude fiber of sorghum malts, caused by germinating grains roots and shoots growth, and the increase of water-soluble pentosans, due to hydrolysis of the non-starch polyssacharides during malting, significantly increased flour and dough water-holding capacity. Thus, crumb structure was improved and crumb firmness and crumb-firming rate decreased. Treatment of sorghum flour with endo-(l-4)-β-xylanase to determine whether endoxylanases could solubilize sorghum pentosans, increased the water-soluble pentosans slightly, indicating the potential of endoxylanases to improve the bread-making quality of sorghum flour. However, heating the endoxylanase treated flour to inactivate the enzyme, so as to determine its specific effect, gelatinized the starch and decreased the bread volume. A natural lactic acid fermentation of sorghum flour, followed by drying at 60°C, decreased the pH of sorghum flour from 6.2 to 3.4 and slightly increased the gelatinized starch and the pasting viscosity of sorghum flour. Apparently, the low pH caused higher loaf volume and improved crumb structure and softness by suppressing the amylases and by increasing the viscosity of dough, and hence increasing its gas-holding capacity. Adding wet fermented sorghum flour directly to wheat flour (sourdough process), as an alternative to drying, further increased the volume and decreased the crumb firmness. Fermentation and drying also improved the protein digestibility of sorghum composite bread. Consumer panel members liked the bread made with boiled sorghum malt flour most, apparently because it was softer, more moist and had a fine malt flavor. They liked the bread made with fern1ented and dried sorghum flour less, apparently because it had a pronounced sour taste. Malting and fermentation can be successfully used to produce acceptable sorghum and wheat composite bread. Fermentation is probably the most suitable technology for poor developing countries because it is simple and effective. Steaming the malt and adding the endoxylanases directly when mixing the dough, to eliminate the flour drying step and to reduce starch gelatinization, should be looked at further. | Food Science | unrestricted