Evaluation of some Newly Developed Diploid Hybrids and their Breeding Value in 4x-2x Crosses

1　Introduction　　The common potato,Solanum tuberosum L.( tbr,2 n=4 x=4 8) ,is a tetrasomic tetroploidwith a very narrow genetic base( Howard,1 970 ) h,to a large extent,limits the progress innew cultivar development.Fortunately,there are still rich germplasm in South America,theorigin center of potato.Potato has approximately 2 2 6 related tuber- bearing species( Harwkes,1 990 ) ,which constitute important reservoirs of genes for resistance to adversebiotic and abiotic stresses.Most of th…

Evaluation of some Newly Developed Diploid Hybrids and their Breeding Value in 4x-2x Crosses

The narrow genetic base in potato (Solanum tuberosum L. ) limits the progress in cultivar development.The rich diploid germplasm in the origin center of potato provide a unique resource for improvement of tetraploid potatoes. Seven newly developed diploid hybrids with 2n pollen production, all of which have S.phureja background,were developed and evaluated for their value in potato breeding. They were crossed as male parnets to six tetraploid Solanum tuberosum cultivars,and seeds in large quantity from eleven crosses were obtained. Main agronomic traits ,such as tuber yield ,tuber number,mean tuber weight ,tuber shape ,eye depth, skin smoothness, flesh color, and specific gravity, were measured for 4x-2x tetraploid progenies in seedling generation ,and their parents as well. All of the diploid hybrids had some merit for specific traits and the DH39 was more promising ;high specific gravity trait in some diploid hybrids was successfully introgressed into tetroploid progenies via 4x-2x crosses. These diploid hybrids have potential value in potato breeding.