Brian P. Forster

Progress in Doubled Haploid Technology in Higher Plants

In the early 1990s, many basic protocols were developed for haploidy and doubled haploidy, but most were inefficient. During the last decade, progress in technology has been achieved mainly by empirical, time and cost consuming testing of protocols; as a consequence success was proportional to the number of laboratories involved. In the most frequently studied crops (barley, wheat, triticale, maize, rice and rapeseed) improved protocols are now used routinely in breeding and although several problems remain the benefits make doubled haploidy well worthwhile. Significant advances have also been achieved in vegetable, fruit, ornamental, woody and medicinal species, though responses in many remain low with legumes being particularly recalcitrant. There has been resurgence in doubled haploids over the last few years with protocols published for almost 200 plant species. The present review aims to show the recent progress in haploid and doubled haploid technology of higher plants.

Production of haploids and doubled haploids in oil palm

BackgroundOil palm is the worlds 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.

Oil Palm (Elaeis guineensis)

Oil palm (Elaeis guineensis) breeding is described with respect to modern challenges facing the oil palm industry. Elaeis guineensis is native to Africa, but now rings the globe as a tropical commodity oil crop. A brief history of the development of the oil palm crop is given to provide a perspective on problems, challenges and breeding opportunities. Basic information is given on oil palm biology, especially reproductive biology and genetics as these are fundamental in determining the breeding methods that can be applied and developed. Since conventional breeding is constrained by the availability of genetic variation, a section is provided on germplasm collection and gene conservation. Current target traits for oil palm, and their underlying genetic controls are listed along with methods for their selection (phenotypic nursery and field trials and genotypic laboratory screens). Basic techniques in crossing (pollen collection, female bunch isolation, pollination, harvesting and seed germination) are illustrated New developments in breeding such as the potential for F1 hybrids, wide hybridisation (e.g. with the related S. American species, E. oleifera), the use of genomic selection (exploiting genome sequence data) and advances in tissue culture are described. A forward vision discusses the potential to exploit emerging biotechnologies for crop improvement including novel traits for mechanical harvesting and specialty oil production.