Verification of the Apomictic Origin of Cactus Pear (Opuntia spp Cactaceae) Seedlings of Open Pollinated and Crosses from Central Mexico
Keywords:Apomixis, cactus pear, nopal, seedlings, cactus breeding.
Nopal is endemic to Mexico but it is becoming an interesting alternative fruit and forage crop for semiarid areas of the world. Few varieties originated from Mexican germplasm support the world market. Nopal is propagated asexually for commercial purposes, but seed propagation is essential for breeding. A main constraint to breeding is apomixis, which has been reported in numerous Opuntias including those of horticultural interest like O. ficus-indica. Apomixis makes difficult the screening of individuals obtained from crosses and complicates genetic studies. In this study 17 breeding populations of Mexican origin all showed the presence of putative apomictic seedlings, although with significant differences. Selfing induced a higher number of apomicts. When the accession CDO was used as a female the number of apomicts also increased, suggesting the presence of a maternal effect. The exploratory RAPD assay of nine seedlings of two populations, selected according to the former criteria revealed that late emergent seedlings showed a similar banding pattern as the maternal entries.