BackgroundOil 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 F1 varieties. The development of such elite lines has thus far been prevented by difficulties in generating homozygous parental types for F1 generation.ResultsHere 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 F1 seed from intercrosses between DH/mixoploids once they develop female inflorescences.ConclusionsThis 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 F1 varieties. The anticipated step increase in productivity may help to relieve pressure to extend palm cultivation, and limit further expansion into biodiverse rainforest.

RESUMO:(Microsporogênes e e etapas da ontogenia do gametófito masculino de Tabebuia ochracea (Cham.) Standley (Bignoniaceae)). Foram analisadas as etapas da ontogenia do gametófito masculino e da parede da antera de TlIbebuia ochracell. O método de formação da parede do microsporângio é do tipo Oicotiledôneo. O tecido esporogênico, em cada microsporângio, visto em secção transversal , organiza-se em uma fileira cel ular em forma de ferradura. O tapete é do tipo secretor e possui odgem dual. O tapete interno diferencia-se precocemente em relação ao tapete externo. As duas camadas tapetais são estruturalmente dimórficas, mas no fim do estágio pré-meiótico elas se tormam idênticas e com característico vacuoma bipolar. O endotécio desenvolve espessamentos helicoidais em suas paredes celulares. O desenvolvimento do pólen segue o modo usual em angiospermas. O expressivo crescimento do nucléolo e o aparecimento de vacúolos nucleolares na célula vegetativa sugerem sua alta atividade biossintetizante.Palavras-chaves: Bignoniaceae, Tabebuill, ontogenia, tapete , placentóide, micrósporos, gametófi-to masculino, pólen, vacúolos nucleolares.ABSTRACT: (Microsporogenes is and the early male gametophyte development ofTabebuill ochracelle (Cham.) Standley (Bignoniaceae)). Oevelopment of the pollen and anther wall of Tabebuia ocilracea was studied. The microsporangial wall follows the Dicotyledoneous type of ontogeny. The sporogenous tissue in each microsporangium, in transverse section, is organized in a celular strip, with a horseshoe outline. The tapetum is secretory and shows a distinct dual odgin. The inner tapetal layer differentiates earlier than the outher layer. The two tapetal layers exibit a distinct structural dimorphism, but before the meiotic divisions of the MMCs the tapetal layers become identical. Vacuolation in each tape tal cell, at this stage, is characteristically bipolar. The

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.Peer reviewe

Seed viability testing in seed processing is carried out to forecast germination levels. The test is destructive and involves removing the embryo from the kernel for visual inspection.

All field and laboratory operations should have standard health and safety protocols. These may vary according to local requirements and standards. Some equipment will also come with instructions on proper use, which may involve training, including health and safety issues. Failure to abide by these can result in accidents and personal injury (serious and minor); neglect of health and safety issues may incur penalties such as fines or cessation in field and laboratory activities. Guidelines in health and safety issues relating to crossing in oil palm are given below.