Biotechnology Journal International

Blast is one of the economically important diseases of rice. Quantitative trait loci (QTL) analysis for partial resistance to leaf blast disease was carried out using 122 RIL population from the cross between Danteshwari (highly susceptible) and Dagad deshi (resistant) in blast endemic area of Ambikapur, north Chhattisgarh, India during wet season, 2013. Analysis indicated that approximately normal distribution of RILs for the trait leaf blast resistance. A linkage map was constructed from 122 RILs using 162 polymorphic SSR markers. Composite interval mapping was employed to identify QTLs. Five QTLs such as “qLB12.1”, “qLB12.2”, “qLB12.3”, “qLB12.4” and “qLB10.1” were identified for leaf blast resistance using RIL population on chromosomes 12 and 10, respectively. The QTLs, “qLB12.2”, “qLB12.3”, “qLB12.4” mapped both seedling and tillering stages of RIL population of rice. The LOD score and phenotypic variation explained by each QTL ranged from 6.898-3.021 and 15.86 - 56.24%, respectively. The qLB12.2 was identified for both stage and found stable across the life of rice for leaf blast resistance. The resistance loci mapped to chromosome 10 specific to second replication. The QTLs identified could be used as a genetic resource in improvement of rice varieties for blast resistance. These findings laid the foundation for the development of a marker-assisted scheme for improving majority of rice varieties that are susceptible to blast and useful for fine mapping studies.

Aims: To determine the effect of various mulches on growth and yield of tomato and to work out the economics of cultivation under protected environment.

Study Design: Randomized Block Design with three replications.

Place and Duration of Study: Research farm, Department of Vegetable Science and Floriculture, CSK HPKV, Palampur during 2016 and 2016-17.

Methodology: The experiment consists of nine different mulch treatments. The observations were recorded viz., days to 50 per cent flowering, days to first harvest, number of nodes/plant, internodal length, plant height, number of fruits/plant, average fruit weight, yield per meter square, harvest duration, net returns and output: input ratio. Observations were recorded on 5 plants chosen at random in each entry and replication.

Results: Significantly highest fruit yield of 10.9 kg/m² was obtained in M₇ i.e. double shaded plastic mulch and was statistically at par with M₆ i.e. black colour plastic mulch (10.2 kg/m²). Mulch showed significant variation in a number of fruits/plant. M₇ i.e. double shaded plastic mulch (40.4) remained statistically at par with M₆ (39.5) and M₁ (38.6) produced significantly more number of fruits/plant. Significantly highest net returns (Rs.147.6/m²) were observed in M₇, as compared to other mulches.

Conclusion: It can be concluded that use of double shaded and black colour synthetic mulch significantly increased the growth, yield and yield contributing characters in addition to net returns in tomato under the protected environment.

Aims: The objective of this work is to characterize the mucilage of food plants from Côte d’Ivoire.

Study Design: Mucilage food plants edible parts were dried, mucilage were extracted and Physicochemical and nutritive constituent content have been evaluated.

Place and Duration of Study: The study was conducted in Laboratory of Biochemistry and Food Sciences, Biosciences Unit, at Felix Houphouet-Boigny University between January and December 2014.

Methodology: The study was carried out on fruits of A. esculentus (okra), B. mannii (sran), I. gabonensis (kplé) and leaves of C. olitorius (kplala) collected. The mucilage of different plants has been extracted. Physicochemical and nutritive constituent content have been evaluated.

Results: The mucilage contents of B. mannii, I. gabonensis, A. esculentus and C. olitorius were respectively 63.00 ± 2.69%, 56.34 ± 5.44%, 34.86 ± 5.27% and 25.81 ± 4.13%. Scanning electron microscope (SEM) observations of the mucilages have showed varying forms. Ash, pH, total polyphenols, lipids, proteins and insoluble fibers differentiated the studied mucilages to p˂0.001. The mucilages obtained are rich in minerals (ash content between 4.11 ± 0.19% and 10.71 ± 0.20%) and soluble fibers (72.86 ± 7.63% and 80.34 ± 5. 58%). These mucilages are very low in energy (36.66 ± 17.44 kcal/100 g at 50.71 ± 30.22 kcal/100 g).

Conclusion: Mucilages of selected plants are rich in ash and have low energy value.

Aims: To determine aflatoxin biosynthetic genes in fungal isolates in relation to aflatoxin levels in maize grain varieties from epidemiologically aflatoxicosis hot spots and non-aflatoxin hot spots agro-ecological zones in Kenya.

Study Design: Purposeful sampling technique was applied targeting regions of variable aflatoxicoses susceptibilities.

Place and Duration of Study: Samples were sourced from Kitui/Kibwezi counties, an aflatoxin hot spot, during 2008-2010 Maize growing seasons. Comparative samples were from Uasin-Gishu county and Perkerra irrigation scheme in Baringo County, both with no previous acute aflatoxicosis and practicing commercial cultivation under rain-fed and irrigation farming systems, respectively.

Methodology: Maize samples (n=295) and fungal isolates (n=61) were analyzed for aflatoxin contamination and presence of aflatoxin biosynthetic genes, respectively. Total aflatoxin quantification was by a commercial Enzyme Linked Immunosorbent Assay (ELISA) kits, Boratest^®, while molecular characterization of Aspergillus flavus (n=40) and A. parasiticus (n=21) isolates applied Quadruplex Multiplex PCR technique encompassing four aflatoxin biosynthetic genes: nor-1, ver-1, omt-A and aflR. Findings from the study variables were analyzed according to maize variety, agro-ecological origin of maize samples and fungal species besides type of farming system.

Results: Uasin-Gishu maize samples (n=158) assayed for aflatoxins belonged to six maize commercial varieties; H614, H629, H6213, H6210, H613 and H628 alongside an indigenous variety, Kipkaa. All Perkerra samples (n=61) also belonged to a commercial variety, H513. Contrastingly, all Kitui/Kibwezi samples (n=76) belonged to an indigenous variety, Kikamba (Kinyanya). The varieties H613, H628 and Kipkaa all had the samples (100%) within the Kenyan statutory safe total aflatoxin limit (≤10.0 ppb) whereas Kikamba and H513 varieties had 82.9% and 83.6% samples within safety limits, respectively. Similarly, the mean aflatoxin content for all the seven Uasin-Gishu varieties was only 1.62 ppb while Kikamba and H513 had means of 14.6 ppb and 15.6 ppb, respectively (P=0.05). Positive PCR amplification results were obtained in 96.3%, 84.2% and 80% for Kitui/Kibwezi, Perkerra and Uasin-Gishu isolates, respectively whereas regional distribution of amplicon spectrum was 6, 3 and 2 out of 8, respectively. A similar regional pattern was established regarding prevalence of PCR positive isolates and whose maize samples of origin also tested ELISA-aflatoxin positive, having been 81.5%, 52.6% and 26.7% for Kitui/Kibwezi, Perkerra and Uasin-Gishu. Interestingly, the only isolate PCR positive for all the four genes under assay and whose maize sample of origin had aflatoxins was coincidentally from Kitui/Kibwezi, an epidemiologically aflatoxicosis  hot spot agro-ecological zone.

Human papillomaviruses (HPVs) belong to the class of DNA viruses which are known to cause different human cancers. Development of new diagnostic methods and tools to study virus biology and mechanism of infection had been strongly felt in order to prevent HPV infections. In the present study we have designed new set of primers from E6 gene of HPV for its detection using PCR with an increased sensitivity of upto 0.2 pg. Hence, we established and characterized a new cervical epithelial cell line designated as CEC to be used as an in vitro tool for studying viral biology in order to prevent HPV infections.  The interaction of HPV with CEC cells resulted in its neoplastic transformation and cytological changes such as multinucleation, nuclear irregularity, nuclear enlargement and perinuclear halos. CEC cell line was thus successfully established as an in vitro model system for studying interaction of HPV with squamous cervical epithelial cells.