January 2010 issue

Genetic variability, character association and genetic divergence in Mungbean (Vigna radiata L. Wilczek)

Rahim MA, Mia AA, Mahmud F, Zeba N and Afrin KS

Abstract

Genotypic and phenotypic variance, coefficient of variance, heritability, genetic advance, correlation and path coefficient were evaluated for yield and its contributing characters in 26 Mungbean genotypes. Significant variations among the genotypes were observed for all the characters. High heritability (broad) along with high genetic advance in percent of mean was observed for plant height, number of pods per plant, number of seeds per pod, 1000-grain weight and grain yield per plant indicating these characters would be best for phenotypic selection. The number of pods per plant, panicle length and number of seeds per pod are positively correlated with grain yield. Based on path coefficient parameter, the number of pods per plant and number of seeds per pod are the important characters. Twenty six genotypes were grouped into 3 clusters. Maximum number of genotypes (12) was grouped into cluster II. The maximum range of variability was observed for number of pods per plant (12.22 - 20.55) among all the characters in 3 clusters. Crosses involving cluster I and III may exhibit high heterosis for yield as well as earliness.

Pages 1-6 PDF

In vitro tuberization in potato (Solanum tuberosum L.)

ME Hoque

Abstract

In vitro microtuber formation potentiality of potato was investigated to establish a rapid disease free seed production system in potato. MS medium supplemented with 4 mg/L of KIN showed best performance in respect of multiple shoot regeneration and microtuber formation. Simple MS medium was not able to produce any micro tuber under in vitro condition. Dark condition better responded to tuberization than light condition. Among the three different explants (nodal segment, sprout and shoot apex) nodal cutting showed the best performance on days to microtuber formation and average weight of microtuber. MS + 6% sucrose + 4 mg/L KIN combination of treatment was best for in vitro tuberization among the parameters under study.

Pages 7-11 PDF

The effect of different plant hormones (PGRs) on multiple shoots of Hypericum retusum Aucher

Süreyya Namli, Filiz Akbas, Çigdem Isikalan, Emine Ayaz Tilkatand Davut Basaran
Abstract

Use of Hypericum species have increased in the past few years due to the antidepressant and antiviral activities found in extracts of those plants. As a result of its potential as a pharmaceutical, a new system was developed for in vitro culture of this species. The goal of this investigation was to produce multiple shoot via in vitro techniques for Hypericum retusum Aucher. In vitro germination of the seeds was standardized on Murashige and Skoog (MS) hormone-free medium. Cultures were initiated from shoots inoculated onto MS medium supplemented individually with nine different concentrations of 6-Benzylaminopurine (BAP) and Kinetin (Kn). The highest number of shoots was obtained on medium supplemented with 0.5 mg l^-1BAP (64.25 shoot/explant). Out of all the investigated concentrations of Kn, the best result was obtained on medium supplemented with 1.5 mg l^-1 Kn (27.87 shoot/explant). In addition, shoots were cultured separately on the media containing BAP (0.5 mgl^-1) andKn (1.5 mgl^-1) combined with three different auxins (0.25 mgl^-1 IAA, IBA, NAA). In view of number and length of shoot the best result was obtained on the medium supplemented with 0.5 mg l^-1BAP + 0.25 mg l^-1IBA (54.12 shoot/explant, 3.36 length of shoot). In the presented study, the use of the BAP alone was the most efficient for shoot propagation. Rooted plantlets were acclimatized and successfully transferred to soil.

Pages 12-17 PDF

Genetic transformation and molecular analysis of polyhydroxybutyrate biosynthetic gene expression in oil palm (Elaeis guineensis Jacq. var Tenera) tissues

Ismanizan Ismail, Nor Fakhrana Iskandar, Gor Mian Chee, and Ruslan Abdullah

Abstract

Bioplastics are an alternative substitute for petrochemical synthetic plastics. Polyhydroxybutyrate (PHB) genes are involved in bioplastic synthesis. In this study, bioplastic synthesis genes were incorporated into the genome of oil palm because this plant has a high concentration of the PHB precursor acetyl-CoA. Immature embryos (IEs) of Elaeis guineensis var Tenera were infected with Agrobacterium tumefaciens LBA4404 that contained the binary vector pJLPHB3, which encoded the phb genes, ß-ketothiolase (bktB), acetoacetyl-CoA reductase (phaB) and PHA synthase (phaC) flanked by a modified CaMV35S promoter, a plastid targeting sequence and the nos terminator. GUS assay revealed that about 78-100% transient transformation frequency was obtained for calluses and 55-65% for plantlets 1 month after transformation. However, GUS assays of leaf tissue from 12-month-old plantlets showed that only 10-33% transformation frequency was obtained. The presence of the phb genes in GUS positive plantlets was confirmed using PCR and multiplex PCR analyses. Southern blot analyses verified that the phb genes were integrated in transformed leaves and calluses using the phaB probe (0.805 kb) and phaC probe (1.730 kb). Quantitative transgene expression comparison in the transformed tissues measured using real-time PCR showed that the expression levels of the phaB and phaC transgenes were 6.06- and 6.02-fold higher compared to the non-transformed oil palm.

Pages 18-27 PDF

Up-regulation of onion bulb glutathione S-transferases (GSTs) by abiotic stresses: A comparative study between two differently sensitive GSTs to their physiological inhibitors
MM Rohman, MS Uddin and M Fujita

Abstract

Among the five GST isoforms (designated as GSTa and GSTb as minor, and GSTc, GSTd and GSTe as dominant GSTs) in onion bulb, GSTc, a phi-type GST, is highly sensitive to the inhibitions its physiological inhibitors. On the other hand, GSTe is less sensitive to such inhibition. In this study, GSTe was purified and its antibody was developed in rabbit antiserum to investigate its stress responses in comparison to those of GSTc. The distributions of GSTe and GSTc were also investigated in healthy onion plants. GSTe was purified 93-fold with a recovery of 3.5%. The purified enzyme showed single band with a molecular mass of 27 kDa in sodium dodecylsulfate-polyacrylamide gel electrophoresis. The expression levels of GSTe and GSTc were greatly varied in indifferent organs. Accumulation level of GSTe was abundant in onion bulb followed by callus, root and mature bulb, but not detected in young leaves. On the other hand, expression of GSTc was detected in all organs, where, the levels were abundant in root and bulb. However, expression level was higher in mature organs than young ones. Stress responses of GSTe and GSTc were examined in onion calli, where the levels of GST accumulation were also different by external stimuli. The level of GSTe was induced significantly in both saline and heavy metal treated calli. However, induction of GSTe was weak in osmotic stress and not detectable in low temperature stress. At the same time, level of increased accumulation of GSTc was detected under all stresses, where osmotic stress (PEG) efficiently induced the expression level. Though these two onion bulb GSTs responded differently to stresses, this study implicated that they have important role in stress combating.

Pages 28-34 PDF