Study On Distinctness,Uniformity And Stability Of Six Intergeneric Hybrids Between Longan And Litchi

Longan(Dimocarpus longan Lour.)and Litchi(Litchi chinensis Sonn.)are the significant economic fruit trees in South China,and all belong to Sapindace family.In recent years,because of single main cultivar structure,highly concentrated mature period,the marketing and industrial benefit of Longan and Litchi were downturn.Therefore,to improve the cultivar and product structures,and then the industrial economic benefits of Longan and Litchi,it is expected to breed the new varieties with stagger mature period,complementary advantages and excellent comprehensive characters through distant hybridization between Longan and Litchi.In this study,six good intergeneric hybrids(Shizi No.19,Shizi No.26,Shizi No.33,Shizi No.52,Zaozi No.1 and Zhongzi No.8)between Longan and Litchi were selected as materials,and their parents as control cultivar.According to the DUS tests guidelines of Longan and Litchi,73 traits of the six intergeneric hybrids were observed to comprehend their Distinctness,Uniforminty and Stablility in correlated character.This could Provide data for new variety protection and new variety examination and approval application,and then provide the theoretical guidance for further breeding.The main results of this study are as follows:1.According to the DUS test,most of the traits showed matroclinal inheritance,however some traits also showed paternal specifity,or transgression and even novelty.2.The interspecific hybrids of Longan and Litchi have obvious heterosis in some traits.For example,Shizi No.19 is stronger than Shixia in fruit aroma;The soluble solid content of Shizi No.33 is significantly higher than its female parent Shixia;The number of pairs of lobules of Shizi No.52 is up to 7 pairs,which is much higher than that of the its high-value parent Shixia.The length and width of the lobules are larger than Shixia which is its high-value parent.The tree vigor of the Zaozi No.1 is stronger than parents,the length of the lobules is also larger than that of the high-value female parent Huanongzao.The number of pairs of lobules of Zhongzi No.8 has 6 pairs,which is much higher than its high-value female parent Zhongqiu No.1.Furthermore,the soluble solid content of Zhongzi No.8 is higher than its female parent Zhongqiu No.1.3.The six intergeneric hybrids showed their specificity.For example,Shizi No.19's distinctness was that the color of rachis was brownish green and the seed shape was elliptic,etc.;The specific traits of Shizi No.26 were inclined fruit shoulder,the Leaf shape of leaf is shallow volume,etc.;The specific traits of the Shizi No.33 were that the top of fruit was round and the color of the peel was yellow-brown,etc.;The specific traits of the Shizi No.52 were the reddish-green color of branches,and the frontal color of the petioles was maroon,etc.;The specific traits of Zaozi No.1 were mainly brown on the surface of the trunk,brown green on the branches,and long blunt on the tip of the lobule,etc.;The specific traits of the Zhongzi No.8 were that the shape of the leafl was long ellipse and the color of rachis was brown green,etc.4.By observing the field traits of six intergeneric hybrids and calculating the coefficient of variation,the results showed that there was no significant difference in quantitative traits,qualitative traits,and pseudo-qualitative traits among different individuals of the same intergeneric hybrid,that is,the traits of the same line had uniformity and also stability.Studies have shown that 6 intergeneric hybrids have Distinctness,Uniformity and Stability compared to the control variety.These hybrids provided material basis for applying for the protection of new varieties.5.Among the six intergeneric hybrids,Shizi No.52,Zhongzi No.8 and Shizi No.19 have obvious excellent(Excellent,E)performance.Shizi No.52 has strong growth potential,leafy foliage,large fruit,late maturity,excellent quality,and the comprehensive traits were significantly better than that of ‘Shixia' Longan.It is known as “extremely late maturation and large fruit size Longan”;Zhongzi No.8 also has strong growth vigor and cold resistance,the fruit quality was excellent with special flavour of jasmine and crisp flesh;The fruit of Shizi No.19 has the aroma of Litchi,fresh food quality is better than Longan,and also has strong cold resistance,late maturity,which can be described as “ late maturation and excellent-quality Longan”.These three intergeneric hybrids have been assigned regional trials,and they can be ready for new species certification after obtaining the data for adaptability(Adaptability,A).