Dunwell J.M.,University of Reading |
Wilkinson M.J.,Aberystwyth University |
Nelson S.,Sumatra Bioscience Pte Ltd. |
Wening S.,Bah Lias Research Station |
And 9 more authors.
BMC Plant Biology | Year: 2010
Background: Oil palm is the world's most productive oil-food crop despite yielding well below its theoretical maximum. This maximum could be approached with the introduction of elite F1varieties. The development of such elite lines has thus far been prevented by difficulties in generating homozygous parental types for F1generation.Results: Here we present the first high-throughput screen to identify spontaneously-formed haploid (H) and doubled haploid (DH) palms. We secured over 1,000 Hs and one DH from genetically diverse material and derived further DH/mixoploid palms from Hs using colchicine. We demonstrated viability of pollen from H plants and expect to generate 100% homogeneous F1seed from intercrosses between DH/mixoploids once they develop female inflorescences.Conclusions: This study has generated genetically diverse H/DH palms from which parental clones can be selected in sufficient numbers to enable the commercial-scale breeding of F1varieties. The anticipated step increase in productivity may help to relieve pressure to extend palm cultivation, and limit further expansion into biodiverse rainforest. © 2010 Dunwell et al; licensee BioMed Central Ltd.
Rees R.W.,University of Bath |
Flood J.,CABI Europe UK |
Hasan Y.,Bah Lias Research Station |
Wills M.A.,University of Bath |
Cooper R.M.,University of Bath
Plant Pathology | Year: 2012
Basidiospores are implicated in the distribution and genetic diversity of Ganoderma boninense, cause of basal stem rot (BSR) and upper stem rot (USR) of oil palm (Elaeis guineensis). Measurement of aerial basidiospores within plantations in Sumatra showed continuous and high production over 24h (range c. 2-11000sporesm -3) with maximum release during early evening. Basidiospores applied to cut surfaces of fronds, peduncles and stems germinated in situ. Equivalent, extensive wounds are created during plantation harvesting and management and represent potential sites for formation of infective heterokaryons following mating of haploid basidiospore germlings. Use of spore-sized micro-beads showed that basidiospores could be pulled up to 10cm into severed xylem vessels, where they are relatively protected from dehydration, UV irradiation and competing microflora. Diversity of isolates from five locations on two plantations was assessed by RAMS fingerprinting. Isolates from within individual palms with USR were identical and represent single infections, but different USR infections had unique band patterns and revealed separate infections. Some BSR-affected trees contained more than one isolate, and thus had multiple infections. There was one example of adjacent BSR palms with the same isolate, indicating vegetative spread, but there were no identical genets from BSR infections and adjacent fallen palms. Isolate diversity was as great within a plantation as between plantations. It is evident that basidiospores play a major role in spread and genetic variability of G. boninense. Evidence for direct basidiospore infection via cut fronds, indirectly through roots via colonized debris and less frequently, infection by vegetative, clonal spread is considered. © 2011 University of Bath. Plant Pathology © 2011 BSPP.
Tohiruddin L.,Bah Lias Research Station |
Tandiono J.,Bah Lias Research Station |
Silalahi A.J.,Bah Lias Research Station |
Prabowo N.E.,Bah Lias Research Station |
Foster H.L.,Bah Lias Research Station
Journal of Oil Palm Research | Year: 2010
Nine trials testing the application of N, P, K and Mg fertilizers to oil palm were carried out at different locations on mineral soils in both North and South Sumatra, and their effect on the contents of both major and minor elements were monitored. This article reports the effect of N, P and K fertilizers on the trace element status of the palms. In four of the trials on old palms in North Sumatra, urea fertilizer significantly reduced the leaf levels of both copper and zinc, in some cases below the established critical levels. In addition, superphosphate fertilizer significantly reduced leaf copper in four of these trials whilst muriate of potash fertilizer significantly depressed leaf zinc in two trials. In contrast, N and P fertilizers had no effect on leaf trace element levels in five trials on younger palms in South Sumatra, but in four of the trials, K fertilizer significantly reduced leaf zinc. There were no consistent effects of N, P and K fertilizers on leaf levels of B, Mn or Fe. Changes in soil properties due to the fertilizer applications did not appear to explain these results. Furthermore, the effects of fertilizers on trace element levels were not generally seen in the rachis, suggesting that the uptake of trace elements into the palms was not significantly affected. The reduction in leaf copper and zinc levels may therefore have been due to a physiological effect of the fertilizer nutrients inside the palms which influenced the transfer of these trace elements to the leaves. Leaf concentrations of other trace elements were not generally affected by fertilizers, indicating that the results for copper and zinc were not due to a dilution effect resulting from increased growth. In the trials on older palms in North Sumatra, yields had generally fallen with time, and Ganoderma incidence had increased in the treatments where trace elements had been depressed by the major fertilizers. It is concluded that continuous application of N, P and K fertilizers is likely to have an adverse effect on the trace element status of oil palms, which if not corrected may result in reduced yields and increased disease incidence.
Posada F.J.,IPM |
Virdiana I.,Bah Lias Research Station |
Navies M.,Malaysian Cocoa Board |
Pava-Ripoll M.,University of Maryland University College |
Hebbar P.,U.S. Department of Agriculture
Journal of Insect Science | Year: 2011
This paper describes the main distinguishing characteristics of female and male pupae and adults of cocoa pod borer, Conopomorpha cramerella (Snellen) (Lepidoptera: Gracillariidae). Two pairs of tubercles present on the sterna of segments IX and X of the female pupae are useful in differentiating female from male pupae. The female genital opening is located anterior to the first pair of tubercles and forms a plateau in which the center has a light brown longitudinal depression that indicates the female genital opening. The male genital opening is a conspicuous, brown, longitudinal slit located between the two pairs of tubercles. The sex of the adult moth can be determined by examining the ventrocaudal segments of the abdomen. The last segment of the female abdomen is white, compressed laterally and at the tip, and the hairy anal papillae can be seen. In the male, the ventrocaudal end of the abdomen is black and robust. This information will be useful for laboratory and field diagnosis and while working on sex ratios of this important pest of cocoa.
Wening S.,Bah Lias Research Station |
Croxford A.E.,Aberystwyth University |
Croxford A.E.,University of Adelaide |
Ford C.S.,Aberystwyth University |
And 9 more authors.
Annals of Applied Biology | Year: 2012
Plant breeders constantly need to introduce desirable new alleles to refresh breeding stocks. This first requires an assessment of potential new sources of material and then identification of genotypes most able to augment existing stocks. Genetic distance analysis is widely used for both purposes, although it measures both haplotype diversity and novel allele abundance. Here, we present a more tailored approach to address these problems. Using oil palm as an exemplar, simple metrics of allelic and genetic richness, graphical genotyping and multivariate analysis were deployed to determine the overall value of Ghanaian germplasm to supplement Sumatra Bioscience (SumBio) breeding material. We next compared three methods to rank individuals. The first was based on multivariate genetic distance. However, we also developed two new systems: Global Allelic Divergence (GAD), based on novel allele abundance, and Genome Scan Allelic (GSA) divergence, which additionally considers genome context. Ghanaian material exhibited increased allelic richness, higher heterozygosity and a higher proportion of private alleles than extant SumBio breeding stocks. Graphical genotyping revealed Ghanaian material as allele-rich in genomic regions that were allele-poor in SumBio breeding stocks. Multivariate analysis showed a collective distinctness and increased variability of Ghanaian plants. Ranks of individuals varied between GSA, GAD and genetic distance. The GAD and GSA ranks correlated strongly with each other but only poorly with the genetic distance-based ranks. We conclude that GSA and GAD are superior ranking systems to identify individuals most likely to introduce valuable new alleles, whilst genetic distance analysis identifies individuals likely to require least backcrossing. © 2012 Association of Applied Biologists.