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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Responses of High Biomass Rice (Oryza sativa L.) to Various Abiotic Stresses

Kondhia, Aditi Nitinkumar 2010 August 1900 (has links)
Rice produces a lot of biomass which is an important trait in increasing grain yield and it is a potential feedstock for bioenergy production. High biomass rice is important to meet the growing demands of grains and biomass for food, fodder and bio-fuel industries. Limited studies have been conducted to determine its response to unfavorable conditions. The main objectives of this study were to determine the response of selected high biomass rice to drought, rainfed and flooded conditions and identify best genotypes that can be grown in unfavorable areas. Two experiments were conducted in summer 2009 to evaluate biomass yield and agronomic traits of selected high biomass genotypes. A greenhouse study had genotypes grown under drought condition - different field capacity (FC) i.e. 100 percent, 75 percent and 50 percent FC, while the field study had rainfed and flooded environments. Most of the genotypes performed well under fully saturated soil conditions but some were less affected by drought. Limited water delayed first tiller emergence and reduced tiller count, rate of tiller production, plant height, rate of increase in height, shoot and root weight, root:shoot (R:S) ratio, percent dry matter (percent DM) and total biomass. The plant height, tiller plant-1, and total biomass at maturity were lower under rainfed conditions and their flowering was delayed compared to flooded conditions. Majority of these traits were correlated with high biomass yield. Genotype 11 which is tall and late maturing produced the highest number of tillers plant-1 and tillers/ 750 cm2 and had the highest biomass yield under both rainfed and flooded conditions. It performed equally well under drought conditions particularly in root and R:S ratio, but genotype 12 was the best in most parameters measured in the greenhouse. Although it was the shortest genotype, it was highest in biomass yield, earliest to tiller, had the highest shoot weight and tiller count, and had the fastest tiller production. The high biomass genotypes like conventional rice were affected by drought and performed better under flooded conditions. However, these two genotypes can produce optimum results under limited availability of water and hence be used for biomass production under stressed environments.
2

Wide Hybridization, Genomic, and Overwintering Characterization of High-Biomass Sorghum Spp. Feedstocks

Whitmire, David Kyle 2011 August 1900 (has links)
The federally mandated 36 billion gallons a year production goal for "advanced biofuels" by 2022 has created a demand for lignocellulosic feedstocks that are inexpensive to produce. The current lack of market development for lignocellulosic feedstocks incentivizes the development of versatile biomass products with greater end-use possibilities, as in either a forage or bioenergy system. High-biomass, perennial grasses offer dual-use potential in either forage or biofuel systems. In 2009 and 2010 controlled pollinations were made to evaluate the efficiency of producing interspecific hybrids between homozygous recessive iap/iap and Iap/- Sorghum bicolor (L.) Moench, cultivated sorghum, and three S. halepense (L.) Pers., johnsongrass, genotypes. The iap/iap genotype removes reproductive barriers to alien pollen in S. bicolor and aids in wide hybridization. Total seed set, germinable seed set, and hybrid production were significantly higher using the iap/iap genotype. The iap/iap S. bicolor genotype is a valuable tool available to plant breeders for the creation of wide hybrids with S. halepense. In a related study a bulked segregant analysis was conducted using bulked samples of S. bicolor, typical flowering S. halepense, non-flowering S. halepense, and putative triploid hybrids of the two species to identify unique markers for each bulk and to evaluate S. bicolor genetic material introgression into the non-flowering S. halepense genome. Thirty-nine and 23 markers were found to be unique to the S. bicolor and typical flowering S. halepense bulks, respectively. These unique markers could be used in a breeding program to identify interspecific hybrids. Alleles at fifteen markers were found in both the S. bicolor and non-flowering S. halepense bulks but not in typical flowering S. halepense and may help explain the non-flowering phenotype. In 2010 and 2011 a study was conducted to investigate the rhizome composition of 11 genotypes of Sorghum species and its relationship to overwintering. Genotype, environment, and sampling date had significant effects on rhizome metabolite concentrations. Overwintering capacity was related to fructans and crude protein concentrations and NIRS (Near Infrared Spectroscopy) was effective at estimating these values. This information can be used to screen for stronger perennial parents to be used in future breeding programs.

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