22 research outputs found
Growth and yield performance of some exotic clones of Hevea brasiliensis in North Kerala region
The growth and yield performance of a set of exotic clones from Malaysia and Ivory Coast was evaluated in comparison with RRII 105, a popular high yielding indigenous clone, for their adaptability in the northern tract of Kerala. The region is characterised by absence of sufficient summer showers and relatively long dry spells. Analysis of growth up to 16 years after planting revealed significant clonal differences in growth pattern, only from the 10th year of planting. Girth and girth increment was the highest in IRCA 130, followed by PB 330. The lowest girth was observed in RRIM 703. The clone IRCA 130 also exhibited significantly high annual and summer yield followed by PB 255. Peak rubber yield was recorded in the month of September irrespective of clones. IRCA 130 showed significantly superior branching height and bole volume followed by PB 255. Incidence of tapping panel dryness (TPD) and pink disease in IRCA 130 was comparable to clone RRII 105. The suitability of the newly introduced clones for the region is discussed
Metabolome-wide association study on ABCA7 indicates a role of ceramide metabolism in Alzheimerâs disease
Genome-wide association studies (GWASs) have identified genetic loci associated with the risk of Alzheimerâs disease (AD), but the molecular mechanisms by which they confer risk are largely unknown. We conducted a metabolome-wide association study (MWAS) of AD-associated loci from GWASs using untargeted metabolic profiling (metabolomics) by ultraperformance liquid chromatographyâmass spectrometry (UPLC-MS). We identified an association of lactosylceramides (LacCer) with AD-related single-nucleotide polymorphisms (SNPs) in ABCA7 (P = 5.0 Ă 10â5 to 1.3 Ă 10â44). We showed that plasma LacCer concentrations are associated with cognitive performance and genetically modified levels of LacCer are associated with AD risk. We then showed that concentrations of sphingomyelins, ceramides, and hexosylceramides were altered in brain tissue from Abca7 knockout mice, compared with wild type (WT) (P = 0.049â1.4 Ă 10â5), but not in a mouse model of amyloidosis. Furthermore, activation of microglia increases intracellular concentrations of hexosylceramides in part through induction in the expression of sphingosine kinase, an enzyme with a high control coefficient for sphingolipid and ceramide synthesis. Our work suggests that the risk for AD arising from functional variations in ABCA7 is mediated at least in part through ceramides. Modulation of their metabolism or downstream signaling may offer new therapeutic opportunities for AD
Temporal stability of growth and yield among Hevea genotypes introduced to a non-traditional rubber growing region of peninsular India
Extensive cultivation of Hevea brasiliensis in India now focus on non-traditional regions for rubber cultivation. As a prelude for selection of genotypes for commercial cultivation, many introduced genotypes are being tested in genotype adaptation experiments in these regions. Present study, reports for the first time, growth and yield adaptation of 28 genotypes in a non-traditional rubber growing region of peninsular India viz., the coastal Karnataka region. Agroclimate of this region was found favoring growth and establishment of all the genotypes evaluated. However, not all the genotypes grew and yielded well. Only four genotypes, RRII 203, KRS 25, PB 260 and PB 235 showed good growth and yield. On grouping, the genotypes fell into categories of moderate high yielders, moderate low yielders and low yielders. The most popular variety of the traditional region, RRII 105 did not perform well in this region. Biological stability in growth and yield of RRII 203 and PB 260 was identified as stable and these genotypes were the best adapted. KRS 25 and PB 235 had unstable yielding pattern. The best identified genotypes can be considered for extensive culture as single clone plantations or as major constituent of clone blends as well as parents in future breeding programmes. Other moderate stable yielders may be used for clone blending in smaller proportions and may be subjected to yield improvement.</span
Temporal stability of growth and yield among Hevea genotypes introduced to a non-traditional rubber growing region of peninsular India
Extensive cultivation of Hevea brasiliensis in India now focus onnon-traditional regions for rubber cultivation. As a prelude for selection of genotypes for commercial cultivation, many introduced genotypes are being tested in genotype adaptation experiments in these regions. Present study,reports for the first time, growth and yield adaptation of 28 genotypes in a non-traditional rubber growing region of peninsular India viz., the coastal Karnataka region. Agroclimate of this region was found favoring growth andestablishment of all the genotypes evaluated. However, not all the genotypes grew and yielded well. Only four genotypes, RRII 203, KRS 25, PB 260 and PB 235 showed good growth and yield. On grouping, the genotypes fell into categories of moderate high yielders, moderate low yielders and low yielders. The most popular variety of the traditional region, RRII 105 did not perform well in this region. Biological stability in growth and yield of RRII 203 and PB 260 was identified as stable and these genotypes were the best adapted. KRS 25 and PB 235 had unstable yielding pattern. The best identifiedgenotypes can be considered for extensive culture as single clone plantations or as major constituent of clone blends as well as parents in future breeding programmes. Other moderate stable yielders may be used for clone blending in smaller proportions and may be subjected to yield improvement
Effect of suprathermal particles on EMEC instability in kappa-Maxwellian distributed space plasmas
Natural convection through spherical particles of a micropolar fluid enclosed in a trapezoidal porous container
Chromosomal characterization of three native and one cultivated species of Lathyrus L. in Southern Brazil
Mitotic metaphase chromosomes and interphase nuclei of nine populations of three South American species of Lathyrus (L. pubescens, L. nervosus and L. crassipes) and six populations of the cultivated species L. odoratus were analyzed. All populations had 2n = 2x = 14 chromosomes. There were significant differences among populations within each species and among species in the number of metacentric, submetacentric and subtelocentric chromosomes, the number and location of secondary constrictions, chromosome length (longest and shortest), total haploid complement, arm ratio, and centromeric index. L. odoratus showed the highest tendency towards karyotype symmetry whereas the three South American species showed a moderate tendency towards asymmetry, with L. pubescens being the most asymmetrical. Silver staining was used to identify the nucleolar organizer regions (NORs) and the number of nucleoli per interphase nucleus in each species. In L. pubescens and L. nervosus, the NORs were located on the secondary constriction of the long arm of pair 7, in L. crassipes, the NOR was proximal being located in the pair of metacentric chromosomes, and in L. odoratus there were four terminal NORs on the short arms of pairs 4 and 5. The four species had a maximum of four nucleoli per interphase nucleus, indicating the presence of four regions with active ribosomal genes in each case.<br>Cromossomos em metĂĄfases mitĂłticas e nĂșcleos interfĂĄsicos em 9 populaçÔes de 3 espĂ©cies sul-americanas de Lathyrus (L. pubescens, L.nervosus e L.crassipes) e 6 populaçÔes da espĂ©cie cultivada L. odoratus foram analisados. Todas as populaçÔes apresentaram 2n = 2x = 14 cromossomos. As diferenças significativas observadas entre as populaçÔes dentro de cada espĂ©cie e entre as espĂ©cies foram: nĂșmero de cromossomos metacĂȘntricos, submetacĂȘntricos e subtelocĂȘntricos; nĂșmero e localização das constriçÔes secundĂĄrias; comprimento dos cromossomos (maior e menor); complemento total haplĂłide; razĂŁo braço longo/braço curto e Ăndice centromĂ©rico. L. odoratus Ă© a espĂ©cie com maior tendĂȘncia simĂ©trica em seu cariĂłtipo, enquanto que nas trĂȘs espĂ©cies sul-americanas os cariĂłtipos tĂȘm tendĂȘncia moderada para assimetria, sendo L. pubescens o mais assimĂ©trico. Com nitrato de prata foi possĂvel identificar as NORs e o nĂșmero mĂĄximo de nuclĂ©olos por nĂșcleo interfĂĄsico em cada espĂ©cie. Em L. pubescens e L. nervosus as NORs estĂŁo localizadas na constrição secundĂĄria do braço longo do par 7, em L. crassipes a NOR Ă© proximal, localizada no par de cromossomos metacĂȘntricos, e em L. odoratus foram observadas quatro NORs terminais nos braços curtos dos pares 4 e 5. As quatro espĂ©cies possuem nĂșmero mĂĄximo de quatro nuclĂ©olos em cada nĂșcleo interfĂĄsico, indicando quatro regiĂ”es com genes ribossomais ativos em cada espĂ©cie