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Only partial resistance has been reported so far in Helianthus species for leaf blight caused by Alternaria helianthi (Hansf.). Therefore, in the present study one to two cycles of recurrent selection based on sporophytic and gametophytic selection was effected to increase resistance to leaf blight in the base population. The base population was synthesized by random mating five diverse early generation breeding lines. The gamete selection was practiced by applying pathogen culture filtrate to stigma and style 1 h before pollination. The selection response was measured by recording observations on percent disease index (PDI) at flowering, 15 d after flowering and at physiological maturity. In both gametophytic and sporophytic selection cycles significant reduction in PDI was observed. The populations improved through gametophytic selection were more promising as the pollen selection could allow high selection intensity and absence of dominance effects. In sporophytic selection the rare favorable allelic combination is hardly detected. The progress in resistance in two cycles of selection was not very high for their use in crop improvement. There is a need to increase the number of cycle of selection to maximize the desirable alleles to achieve high level of resistance. The gametophytic selection combined with the conventional sporophytic selection can be considered as an effective tool in improving populations for partial resistance.

Heterosis breeding is a potential technique to improve yields in sesame. Twenty-four diverse sesame genotypes were used as male parents and highly adoptable 3 local varieties were used as female parents. Thirty-eight hybrids were produced during rabi, 2013 and were evaluated along with parents and 3 checks during summer, 2014 in Randomized Block Design at Regional Agricultural Research Station, Polasa, Jagtial, India. The data was recorded for 8 biometrical traits viz., days to 50% flowering, days to maturity, plant height, number of primary branches per plant, number of capsules per plant, capsule length and number of seeds per capsule, 1000-seed weight and seed yield per plant. In this study, highly significant differences were recorded among sesame hybrids for all the traits studied. Further, 2 hybrids Swethathil x VS 07-023 and Swethathil x JL SEL 05-3 had recorded highest standard heterosis of 13.40% and 10.70% respectively. The same hybrids recorded statistically significant superior seed yield per plant ie., 28.7 g and 28.0 g respectively. These potential crosses can be utilized for further breeding program to develop potential purelines. [ABSTRACT FROM AUTHOR]

A naturally occurring fabric belonging to the species Hardwikia binata was extracted from the sheath of stem, bark, and branches of the tree. The fabric specimens were treated with sodium hydroxide and poly (vinyl alcohol). The morphology of the fabric specimens before and after NaOH treatment was studied using scanning electron microscopy technique. Ligno-cellulosic properties of fabric were analyzed by XRD, FTIR, and thermo gravimetric methods before and after NaOH treatment. Tensile strength and percentage of elongation at break of the fabric were also studied by using a universal testing machine (model AGS-10kNG). The results showed that the poly (vinyl alcohol)-treated fabric specimens showed higher tensile strength than sodium hydroxide-treated fabric specimens. The Binata fabric has good thermal resistance and was also found to increase by alkali treatment. The FTIR method indicates lowering the hemi cellulose and lignin content by alkali treatment in the fabric. Further, the X-ray diffraction studies revealed an increase in crystallinity of the fabric by alkali treatment. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 [ABSTRACT FROM AUTHOR]

Phenolic resin based coir/glass hybrid composites were developed using compression molding followed by hand lay-up technique. Mechanical properties such as tensile and flexural properties of coir based hybrid composites were investigated as a function of fiber content and fiber volume fraction. This study is focused on the mechanical performance of coir based and its hybrid composites. Results showed that tensile properties increase with increasing fiber content. Mechanical properties of composites with increased glass fiber content have high values. The effect of alkali-treatment of fibers on the mechanical properties was also studied. Significant improvement in coir based composites by alkali-treatment was observed. Overall studies indicated that the short coir/glass fabric hybrid polyester composites are promising candidates for structural applications where high strength and stiffness is required. [ABSTRACT FROM AUTHOR]

The natural fiber composites based on kapok/sisal and its hybrid composites with polyester as resin matrix have been prepared and tested for mechanical properties. In this paper hardness and flexural properties of kapok/sisal composites were determined with reference to the fabrics content and varying the volume ratios of fabrics. The maximum strength in the properties determined is observed for the optimum fabric loadings. The effect of alkali treatment of fabrics on polyester composites reinforced with kapok/sisal fabrics was studied. Increasing the sisal fiber content resulted in a reduction in the hardness and flexural properties. The properties were found to increase with alkali treated fabrics used in composite. The properties of kapok/polyester composites are found to be better than those of kapok/sisal polyester composites. [ABSTRACT FROM AUTHOR]

The unsaturated polyester-based hybrid composites were developed by combining the kapok and glass fabrics into polyester matrix. This study describes the flexural, compressive, and interlaminar shear resistance properties of kapok/glass polyester composites with and without alkali treatment of fabrics. These properties increase with increasing glass fabric content in composite. The mechanical performance of kapok/glass composites is excellent. The kapok/glass hybrid composites exhibited higher flexural and compressive values than sisal/glass and kapok/sisal composites. [ABSTRACT FROM AUTHOR]

The naturally occurring fabrics belonging to the species Ceiba pentandra and Agave Vera Cruz were used as reinforcements in the present study. The unsaturated polyester (UP) resin based kapok/sisal hybrid composites were developed by the hand lay-up technique at room temperature. The variations in mechanical properties such as compression strength and modulus, chemical resistance and thermal characteristics of these composites are evaluated as a function of fabric/fiber content and different volume ratios of fabrics. The addition of a relatively small amount of sisal fiber to kapok reinforced polyester matrix enhancing the compressive properties of the resulting hybrid composites. A significant improvement in compressive properties of these hybrid composites has been observed by the NaOH treatment. Among all the resultant hybrid composites those with fabrics ratio of 1 : 3 demonstrate improved compressive properties. The chemical resistance of these hybrid composites to different chemical reagents and water was studied. [ABSTRACT FROM AUTHOR]

The naturally occurring fabric belonging to the species Ceiba pentandra, which is commonly known as kapok, is abundantly available in India. The surface of alkali-treated and untreated kapok fabric was coated with unsaturated polyester, epoxy resin, polymethyl methacrylate (PMMA) and epoxy/PMMA blend matrix. The chemical resistance of this fabric to different chemicals and tensile properties was studied. The effect of alkali-treatment (NaOH) on the tensile properties of the fabric was also studied. It was observed that the coated fabric specimens show better chemical resistance and tensile properties than uncoated ones. The tensile properties increased on alkali-treated fabric, which was identified from the results. Epoxy/PMMA coated fabric specimens have better chemical resistance and tensile properties compared to other matrix materials. These observations indicate that the Kapok fabric and the epoxy/PMMA blend are suitable materials for making eco-friendly composites. [ABSTRACT FROM AUTHOR]

The mechanical properties of short uniaxially-oriented intimately-mixed kapok/glass fabric-reinforced polyester hybrid composites were investigated with reference to the fabric content, keeping the volume ratios of kapok to glass at 1:0, 3:1, 1:1, 1:3, and 0:1. The 9 vol% of fabric for kapok/glass was optimized. Hybrid composite materials were made by hand layup technique. The mechanical properties like tensile and hardness properties of the composites were studied. Best results were obtained for composites having increased glass fabric content in kapok/glass. The effect of alkali treatment of fabrics on the mechanical properties of these kapok/glass hybrid composites has also been studied. A significant improvement was observed in tensile and hardness properties of these composites by alkali treatment. Tensile properties were found to be better in composites having volume ratios of kapok to glass at 1:3 ratios. The hybrid composites exhibited good properties compared to the single kind of fabric/polyester composites. [ABSTRACT FROM AUTHOR]

Natural fabric-based thermoset composites are generally lower in strength performance compared to hybrid composites. However, they have the advantages of design flexibility, cost effectiveness, lack of health-hazard problems and recycling possibilities. Hybridization with some amounts of synthetic fibers makes these natural fabric composites more suitable for technical applications such as automotive interior parts. Kapok fabric is one of the important lignocellulosic plant fabrics and has been used as a reinforcement for hybridizing with glass and sisal fabrics in polyester matrix. This study focused on the performance of impact properties of kapok/ glass and kapok/sisal fabrics reinforced polyester hybrid composites. Results show that hybridization with glass fabric enhanced the performance properties. Similarly, addition of kapok fabric to sisal/ polyester composites enhanced the properties. The effect of alkali treatment of fabrics on impact strength of these composites was studied. Notched Izod impact strength of the hybrid composites exhibited great enhancement (34%). Analysis of fabric distribution in the composite and fracture surface was performed to study the breakage and fracture mechanism of the fabric. Also, we studied the thermal properties of kapok/glass and kapok/sisal fabric reinforced polyester composites. [ABSTRACT FROM AUTHOR]