| Potatoes are currently the fourth largest food crop in China.After entering the 21 st century,China’s potato production has grown rapidly and has become the world’s largest potato producing country.Potato is one of the important cash crop in China,which plays an important role in increasing agricultural production efficiency,increasing farmers’ income and adjusting the planting structure.Most of the potatoes used in production are cultivated species,most of which are tetraploid.However,diploid potatoes accounting for around 70% of the total potato resources.Compared to tetraploid germplasm potatoes,they have more diversity.Most of the wild potato varieties are diploid,and during long-term coevolution with pathogens,diploid wild potato varieties have developed their own disease resistance defense system and contain a large number of insect resistance,disease resistance,and stress resistance genes.However,the poor agronomic traits of wild potato varieties hinder their further application.Conversely,Cultivated potatoes possess good agronomic traits but susceptibility to diseases and poor stress resistance.Therefore,it is particularly important to achieve complementary advantages through hybridization between wild and cultivated species.In order to accelerate the process of diploid breeding and select more excellent potato hybrid combinations,this study selected the wild species S.microntum and the original cultivated species S.phureja,which have been screened by the research team for many years,as male parents,and the diploid cultivated species and the original cultivated species S.stenotomus,which were introduced from Canada,as female parents.16 hybrid combinations hybridize successfully with 4 incomplete diallel crosses.Agronomic traits in the F1 generation of 16 combinations,including yield,tuber number,late blight resistance,were evaluated and the combining ability of related traits were analyzed.Based on combining ability effects of agronomic traits,hybrid combinations with high yield and disease resistance were selected to accelerate the process of diploid potato breeding.The main results of this study are as follows:1.The general combining ability(GCA)of resistance in 8 parental materials is as follows: PI21-57-9<PI21-55-14<PI21-55-10<CP14<D5<D8<PC198-30<PI13-20-1,which shows wild species are higher than cultivated species,The general combining ability(GCA)of the yield of 8 parental materials is as follows: CP14<PI13-20-1<PI21-55-14<PC198-30<D8<D5<PI21-55-10<PI21-57-9,which shows cultivated species are higher than wild species.2.PI21-55-10,PI21-57-9,PI21-55-14,CP14 have high special combining ability in resistance to late blight with PI13-20-1 and PC198-30,respectively,which could be resistant hybrid combinations,PI21-55-10 and D8,CP14 and PI13-20-1,PI21-57-9 and PC198-30,PI21-55-14 and D5 have high special combining ability in yield,which could be high-yield hybrid combinations,PI21-57-9 and PC198-30 have a high special combining ability in the tubers number,which could be hybrid combinations with more tubers.CP14 and PI13-20-1,PI21-57-9 and PC198-30,PI21-57-9 and D5,PI21-55-14 and PC198-30,PI21-55-10 and D8 have high special combining ability in plant height,which could be hybrid combinations with reasonable plant height,CP14 and D5,D8,PI21-55-10 and PI13-20-1,PC198-30,PI21-55-14 and PC198-30,PI21-57-9 and PI13-20-1 have high special combining ability in stolon length,which could be hybrid combinations with suitable stolon length.3.The combinations with high special combining ability include PI21-55-10 × PI13-20-1,PI21-55-14 × D5,PI21-57-9 × PI13-20-1,PI21-57-9 × PC198-30,PI21-55-10 × D8,PI21-57-9 × D8.By crossing cultivated and wild species,resistance could be improved and hybrid combinations with excellent comprehensive traits could be achieved. |
