| Walnuts was an important woody oil tree species in Shandong Province.The development of walnut industry was restricted by its unclear rootstock-scion combination and low grafting survival rate.Four walnut rootstocks used in Shandong Province were used as experimental materials in this paper.The healing process of walnut rootstocks with 'Xiangling' and'Yuanlin'ere observed by scanning electron microscopy(SEM).The growth and fruit quality of the combination were determined and analyzed,and the suitable rootstock-scions combination for walnut cultivation in our province were screened out.The grafting breeding technology of improved walnut varieties was improved,which provided support for walnut seedling breeding and promotion of good varieties in our province.The main results were as follows:1.Callus cells were abundantly produced 7 days after budding,but no callus was found after the scion grafting 5th day.A large number of callus were found at the joint of the rootstock,and the new shoots length were up to 5cm-10cm after scion grafting 10th to 30th day.The growth and fruit quality of different varieties were comprehensively and analyzed.The new shoot growth mainly utilized the storage nutrients in the scion.Healing process observed by SEM were similar between 'Jizhaomian' and 'Yuanlin' grafted on black walnut or pterocarya stenoptera rootstock.The tissue cells were found after grafting 20th.The 'jizhaomian' and'Xiangling' rootstock grafted 'Yuanlin' have been found to have callus after grafting 10th.'Yuanlin' scion/'Jizhaomian' and 'Xiangling' rootstock combinations could be quickly healed.It was beneficial to the growth of seedling.2.With 'jizhaomian' as rootstock,grafting 'Qiangfeng','Fengshuo','Lvqing','Lvxiang' walnut,the seedling length,bud spacing,thickness and dry matter accumulation of different varieties were different.Bud spacing could be used as an important character index to distinguish different grafted varieties.The quality of walnut seedlings was analyzed by principal component analysis method,and three main components were selected to evaluate the quality of walnut seedlings.The variance contribution rate of first principal component was 59.6%,and the main root quality coefficient was the largest.The variance contribution rate of the second principal component was 22.85%,and the coefficients of dry matter mass,scion length and scion thickness were larger.The variance contribution rate of the third principal component was 10.02%,and the coefficient of stock thickness and stock quality was larger.The quality of grafted seedlings of four walnut cultivars was evaluated by considering the quality of main roots.3.Grafting 'Yuanlin','Lvxiang' and 'Qingxiang' with 'jizhaomian' as the rootstock,the tree height of 'lvxiang','qiangxiang' and 'yuanlin' were 2.99cm,2.97 cm and 2.66cm respectively.'Yuanlin' could obtain the highest yield which was 6.42kg/plant.Comprehensive the quality of nuts we found that 'Lvxiang' was the best.Considering the early fruit setting capacity,growth potential and strong resistance,we considered that 'lvxiang' scion/'Jizhaomian' rootstock combinations was a suitable combination of varieties in the region.4.After pterocarya stenoptera grafted with 'Xiangling',the quality of the nut fruit increased significantly,which was 27.74%higher than the control.The nut shell thickness decreased significantly,and the shell thickness decreased by 25.23%.There was no significant difference in protein,fat and polyphenol content.The content of nucleophilic phenylalanine decreased,but the content of other amino acids increased.The content of alanine,isoleucine,cystine and methionine changed significantly.5.A breeding method was developed to improve the cultivation of seedlings.The grafting time of the buds was 7-10d ahead of the traditional method.The survival rate of walnut scion grafting was about 85%,and the seedling emergence rate of the best seedlings were up to 80%. |
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