排序方式: 共有4条查询结果,搜索用时 15 毫秒
1
1.
Summary The objective of this study was to find measurable characters to aid the plant breeder in predicting both rubber percentage and rubber yield of guayule (Parthenium argentatum Gray). A field of 234 guayule breeding lines was harvested by clipping in February 1986. Forty-two of these lines were selected for further evaluation on the basis of superior regrowth, rubber content and yield. These 42 lines were reharvested in February 1987. Nineteen variables were evaluated including percent rubber and resin, rubber and resin yield (g/plant), plant height (cm), width (cm), and volume (m3), fresh and dry weight (kg/plant), percent dry weight, stem number, mean stem diameter (cm), total and mean stem circumference (cm), total and mean stem area (cm2), total stem circumference/total stem area (cm-1), and regeneration at two dates. Dry weight (kg/plant) had the best correlation to rubber yield (r=0.85), and plant volume best predicted dry weight (r=0.83). These variables did not correlate as highly with percent rubber. The best statistical regression model for percent rubber included four variables, fresh and dry weight, percent dry weight, and plant volume. This model accounted for 51% of the variation. In comparison, the best regression of rubber yield had an R2=0.85 for plant height and width, volume, and dry weight. 相似文献
2.
Sreekala G. Bajwa Dilpreet S. BajwaGreg Holt Terry CoffeltFrancis Nakayama 《Industrial Crops and Products》2011,33(3):747-755
This study was conducted to evaluate the suitability of using residual plant fibers from agricultural waste streams as reinforcement in thermoplastic composites. Three groups of plant fibers evaluated included cotton burrs, sticks and linters from cotton gin waste (CGW), guayule whole plant, and guayule bagasse. The plant fibers were characterized for physical (bulk density and particle size distribution) and chemical properties (ash, lignin and cellulose contents). A laboratory experiment was designed with five fiber filler treatments, namely control (oak wood fiber as the filler - OWF), cotton burr and sticks (CBS), CBS with 2% (by weight) second cut linters (CBL), CBS with 30% (by weight) guayule whole plant (CGP), and CBS with 30% (by weight) guayule bagasse (CGB). The composite samples were manufactured with 50% of fiber filler, 40% of virgin high-density polyethylene (HDPE), and 10% other additives by weight. The samples were extruded to approximately 32 × 7 mm cross-sectional profiles, and tested for physico-mechanical properties. The CBS and CBL had considerably lower bulk density than the other fibers. Cotton linters had the highest α-cellulose (66.6%), and lowest hemicellulose (15.8%) and lignin (10.5%) of all fibers tested. Guayule whole plant had the lowest α-cellulose and highest ash content. Both CBS and guayule bagasse contained α-cellulose comparable to OWF, but slightly lower hemicellulose. Evaluation of composite samples made from the five fiber treatments indicated that fibers from cotton gin byproducts and guayule byproducts reduced the specific gravity of the composites significantly. However, the CBS and CBL samples exhibited high water absorption and thickness swelling, but the addition of guayule bagasse reduced both properties to similar levels as the wood fiber. The CGP exhibited significantly lower coefficient of thermal expansion. Composite samples with the five different fiber fillers showed similar hardness and nail holding capacity, yet oak fibers imparted superior strength and modulus under flexure and compression with the exception of the compressive modulus of CGB composites. In general, both cotton ginning and guayule processing byproducts hold great potential as fiber fillers in thermoplastic composites. 相似文献
3.
4.
Summary A selected group of 42 guayule (Parthenium argentatum Gray) lines were evaluated on the basis of various morphological characteristics and compared to a total population of 234 lines. The objective of this study was to determine the amount of variation that existed both within and among guayule lines over a 2-year period. The parental lines all reproduced apomictically, and as expected, many lines exhibited a high degree of uniformity for every measured character. However, many other lines were extremely variable for varying numbers of characters. This appears to be due to varying degrees and combinations of apomeiosis, thus establishing a long-term source of genetic variation. The high amount of variability existing among and within these guayule lines indicates that significant progress by selection for both rubber percentage and yield is feasible. 相似文献
1