Studies On The Propagation Technology Of Walnut ’Xinfeng’

Walnut, also called pecan, is China’s long history of cultivation, widely distributed species germplasm resources are extremely rich one, but also economic, timber and multipurpose afforest important species, and walnut fruit delicious, nutritious, Chinese herbal medicine and food processing finest raw materials, the production of dried fruit in the world, occupies an important position. With China’s walnut industry, walnut seedling technology has become increasingly important. In this paper, propagation technique such as seed germination, cutting and grafting of walnut ‘Xinfeng’. The research including: different seeding time and different ways of seed treatment on seed germination of walnut ‘Xinfeng’; different auxins and concentrations on cutting; different grafting pattern; dynamic changes of germination-related and rooting-related physiological biochemical indexes. The aim of studies is to provide scientific basis and technological guide for walnut’s propagation. The main results are as follows:The seed emergence rate and the seedlings growth of walnut ‘Xinfeng’ were influenced by Seeding time. The results showed that the emergence rate and seedling growth were higher in the way of autumn sowing than in the way of spring sowing, with 78% emergence rate, 42 cm seedling height, 0.85 cm diameter.Seed germination rate was affected by the seed treatment. The test showed that the seed germination rate by stratification was higher than the way of being sown immediately after harvest. In addition, the seed germination was influenced by different ways of seed soaking in stratification, and the seed germination rate by stratification with GA3 soaking was higher than stratification with water soaking. The seed germination rate of the way of stratification with GA3 soaking, the way of stratification with water soaking and the way of being sown immediately after harvest were 93%, 83% and 78% respectively.With the increase of germination days, the storage of starch and soluble sugar content in the seed gradually declined. The change trend was same, but rangeability was different in the way of stratification with GA3 soaking, the way of stratification with water soaking and the way of being sown immediately after harvest. The content dropped fastested was in the way of stratification with GA3 soaking. In the early period, the soluble protein content showed a downward trend in all of the three treatments, with the fastest downward in the way of stratification with GA3 soaking. In the late period, the soluble protein content showed a rising trend in all of the three treatments.The cutting of walnuts ‘xinfeng’ was affected by different substrates. The research showed that the best cutting result was the treatment in the substrate(pearlite and vermiculite volume ratio as 1:1)with the highest rooting rate, the earliest produce of callus and adventitious roots, and the most number of adventitious roots.The cutting of walnuts ‘xinfeng’ was also affected by the kinds and concentrations of auxin. Auxin treatment in low concentration could increase rooting percentage and restrain rooting percentage in high concentration. ABT had the most significant effect on rooting of cuttings, and the rooting rate and number could reach 83% and 14 by 250 mg/L ABT treatment.The adventitious roots arised from lenticel based on the cuttings through morphological characteristics observed. This showed that the rooting type belonged to type of cortical root growing.The studying of rooting mechanism indicated that the activity of POD, PPO and IAAO correlated with rooting significantly. ABT treatment increased the activity of POD and PPO, and decreased the activity of IAAO, which would be benefit for the propagation. The activities of PPO and IAAO appeared tendency of “enhancing-descending”, and the activities of POD was “enhancing-descending- enhancing- descending”with two peaks. The content of soluble sugar was“descending-enhancing”in the rooting process.Through the comparison of three kinds of grafting methods, patch budding was the best method in walnut ‘Xinfeng’ grafting, and it’s grafting survival rate could reach 93.33%.