Colchicine-Enabled Genomic Doubling In Oil Palm (Elaeis Guineensis Jacq.)

The African oil palm (Elaeis guineensis. Jacq.) is an oleaginous tree belonging to the family Arecaceae. The crop is naturally a diploid species (2n = 2x = 32) and the most important oil bearing perennial tree crop cultivated in tropics. In spite of its huge economic importance, it has a very narrow genetic base making its improvement using conventional techniques very difficult. All commercial planting materials are hybrids derived from heterozygous pisifera and dura parents. The imperativeness of generating adequate novel materials with sufficient genetic diversity in order to increase progress in oil palm improvement is therefore, very essential. Genomic manipulations through chromosome doubling may present opportunities to broaden the genetic base and increase the diversity within the commercial oil palm species. Developing an efficient genome doubling protocols using anti-mitotic agents is very important in this respect. It will also complement haploid/doubled haploid production efforts by enabling successful deployment of doubled haploids in oil palm breeding programmes. The objectives of this study were, therefore, to optimize genomic doubling in oil palm by determining optimum colchicine concentrations and also outline procedures for screening for putative polyploids. Oil palm seedlings were subjected to colchicine treatment at concentrations of 0, 1.26, 3.76, 6.26 and 8.76 mM for 0, 3, 6, 12 or 24 hours. The colchicine treatment produced variable physio-morphologies in the treated seedlings. Principal component analysis and agglomerative hierarchical clustering of genotype dependent treatments were carried out to provide an ordination guide. The response of oil palm seedlings to colchicine treatment showed genotypic, concentration of colchicine applied and treatment duration dependency. Ploidy level analysis of the colchicine treated seedlings revealed that polyploidization in oil palm increased significantly (p ≤ 0.05) with increasing colchicine concentration. Seedlings of the genotype G-131 responded more favourably to the colchicine treatment than seedlings of G-132. Optimal colchicine concentration for genome doubling in G-131 (28.9 %) and G-132 (17.8 %) was 8.76 mM applied for a period of 24 h. A population of 154 tetraploids out of 1800 seedlings of the two genotypes mutagenized has been identified and being raised for further evaluation and genetic exploitation.