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March 2008

Table of Contents

Potential use of rice straw as filler in eco-composite materials

Buzarovska A, Bogoeva-Gaceva, Grozdanov A, Avella M, Gentile G, Errico M.
                                                                                                           (PDF Link)

Abstract
Rice straw filled composites were prepared from poly (hydroxybutyrate-co-hydroxyvalerate) (PHBV) copolymer containing 13% (mol) hydroxyvalerate. The effects of rice straw content on thermal and mechanical properties of the composites were investigated. It was shown that the value of tensile modulus value almost doubled with the increase of rice straw content, while the tensile strength slightly decreased, compared to pure PHBV resin. Differential scanning calorimetry (DSC) and thermogravimetry (TGA) results have demonstrated a minor effect of the rice straw on thermal behavior of PHBV resin. PHBV/RS composites are expected to be developed as materials for structural application, especially for panelized components with good thermal insulation, intended for improvement of the energy efficiency in eco-buildings.

Keywords: Rice; Poly (hydroxybutyrate-co-hydroxyvalerate) eco-composites; straw


Identification of markers linked to agronomic traits in globe artichoke

Eugenia Martin, Vanina Cravero*, Andrea Espˇsito, Fernando Lˇpez Anido, Leonardo Milanesi and Enrique Cointry.

                                                                                                                                               
(PDF Link)
Abstract

Color head and precocity of production are two important agronomic traits in globe artichoke which determine the acceptance of the product in the market. 118 F2 plants were analyzed for two agronomic traits, color head and precocity of production. Bulked Segregant Analysis (BSA) and Sequence-related amplified polymorphism (SRAP) were used to detect molecular markers linked to the traits. Ten plants with the same trait were used to constitute the bulks, which were screened with seven SRAP pair primers. We detected one band/marker that may be linked to the green color head and one band/marker that may be associated with precocity in head production. The results obtained show that the BSA and SRAP analyses are useful to identify molecular markers associated with agronomic traits. The identified markers will potentially be used in molecular marker aided-selection (MAS) for breeding programs in globe artichoke. 

Keywords:
Globe artichoke, Molecular markers, SRAP, BSA, MAS.


Characterization of radiation induced and tissue culture derived dwarf types in banana by using a SCAR marker
                                                                                       (PDF Link)

P. Suprasanna*, Meenakshi Sidha, T.R. Ganapathi

Abstract
In banana tissue cultures, the occurrence of dwarf off types is a common phenomenon and their detection become relevant. In this study, tissue culture derived (somaclonal) and radiation-induced off types in banana cultivars. Robusta and Giant Cavendish were analyzed using a SCAR-based molecular diagnostic technique. The dwarfs were initially characterized at maturity, by height, leaf shape, pseudostem height and other agronomic characters. At the molecular level, amplification with the SCAR primer resulted in an expected amplified fragment of 1500 bp in normal but not in the dwarf types. Further in a multiplex PCR, an internal positive control was included using primers for 18S rRNA which gave amplification in both the normal and dwarf types. This study shows that the dwarf off-types isolated through tissue culture and radiation-mutagenesis were true dwarfs, validated by using the dwarf-specific RAPD marker for banana.

Keywords:
Banana; Dwarfs; In vitro; Irradiation; Multiplex PCR; SCAR marker


Time of emergence determines the pattern of dominance of rice tillers

Pravat Kumar Mohapatra*  and Ekamber Kariali
                                                                                                            (PDF Link)
Abstract
A large number of later-initiated tillers of semidwarf rice cultivars become either less- or un-productive at maturity. Rice cultivar Lalat was grown in pot (2001-02, Sambalpur University) and field (2004, Regional Research and Technology Transfer Station, Chiplima). The phenological and morphological development, assimilate contents and grain yield of the panicle of different categories of tillers were assessed in order to find out the bias against development of the less productive tillers. The order of dominance of the tillers decreased acropetally in both the conditions. In contrast to the field, the plant tillered profusely in pots. The duration of vegetative and reproductive periods of the late-initiated tillers were short as events like tiller emergence, booting and anthesis were delayed in them, but maturity date was more synchronized. Among tillers, panicle grains yields and assimilate concentration decreased with durations of vegetative and reproductive growth. The concentration of soluble sugars was highest at anthesis and differed among the classes of tillers with lower concentration in the late-initiated tiller compared with the early-initiated tillers.   The concentration of soluble sugars at anthesis correlated positively with grain yield. Absence of late-tillers in the field-grown plants increased dominance of early-tillers and prompted higher partitioning of assimilates to panicle at crucial stages like booting and anthesis for benefit of grain yield. In contrast, late-emerged tillers of the potted plants having biomass less than 2.5 g possessed poor sink organogenesis and failed to use assimilates partitioned in their favour to achieve reasonable grain filling.

Key words:  assimilates; dominance; emergence; grain yield; panicle; rice; spikelet; tillers


The infuence of Imidazole fungicides on multiplication in vitro of pyrodwarf pear rootstock
                                                                                                            (PDF Link)

Djurdjina Ru×ic*, Tatjana Vujovic, Slobodan Milenkovic, Radosav Cerovic, Rade Miletic

Abstract
Pyrodwarf, low vigorous pear rootstock was used as a model plant in these investigations. Under the in vitro conditions, successful micropropagation of this genotype is largely based on the nodal transplantation of shoots due to low potential of lateral shoots to form. Therefore, the objective of these investigations was to study the influence of imidazole fungicide Prochloraz on the multiplication. The commercial chemical SPORTAK 45-E-450, which contains active substance Prochloraz (N-propyl-N-[2-(2,4,6-trichlorphenoxy)-ethyl]imidazole-1-carboxamide), was used as the source of the imidazole fungicide. The experiment was performed during the multiplication phase, and it involved the study of 19 types of media which included MS macro and micro salts, different prochloraz concentrations, BAP, IBA and GA3. Prochloraz involved 3 concentrations (1, 5 and 10 ÁM), either individually or combined with BAP (4.4 ÁM), IBA (5 ÁM) and GA3 (0.3 ÁM). Upon the second subcultures, the parameters of the shoot multiplication, multiplication index and the length and the number of leaves on axial and lateral shoots were determined. Fresh and dry shoot weight, i.e. callus, stem and leaves were also checked. The highest multiplication index (1:2.72) was obtained at the medium which contained 10 ÁM of prochloraz combined with 4.4 ÁM BAP and 0.3 ÁM GA3, individual multiplication index being even up to 1:6. Individual or IBA combined application of fungicides affected the shoot rooting of the Pyrodwarf (up to 100%). The obtained results suggest that Prochloraz intensifies the effect of the added exogenous BAP on in vitro multiplication of the Pyrodwarf pear rootstock and could be recommended for micropropagation of this rootstock. 

Keywords
: imidazole fungicides; in vitro; multiplication; pear rootstock; rooting

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