Studies On The Introduction And Highly Efficient Seedling Production Techniques Of Black Walnut (Juglans Nigra)

The American black walnut for the breed resources introduction, saplings nurture, biology observation, fertility planting, grafting and so on, was studied. The experiment included the following aspects:1. We introduced into the eastern black walnut tree seeds for nurturing technological research from Pennsylvania in America. We explored the ways to improve the germination rate, the adaptability of saplings and the rapid development technologies of seedlings. Treated with the low temperature, GA and hastening germination, the germinative rate of the seeds increased to 82%. The average height of 2-year-old seedlings reached to 3.15m, and the average diameter at 1m above the ground was 2.38cm. The heights and diameters of 2-year-old seedling were little different in different soil types. The plant percents of the grafted seedlings, with Xinjiang walnut as stock, were 78.9% and 33.6% respectively by two different grafting methods.2. The cultivating tests were carried with the four cultivars of Eastern Black walnut: Bill 81-143, Mintle, Peanut and Wrights. The results showed that Wrights'fruits were the largest of the four cultivars, the average weight per fruit of Wrights was 0.79kg, and the productivity per tree takes turns from Wrights to Mintle, Bill and Peanut. The ratio of kernel and fruit of Wrights was the greatest, to 34.66%.3. The methods were developed to graft 3-year-old black walnut as stock, with Chinese walnuts (cv. Xiangling and Yuanfeng) as scion. The viabilities of both Xiangling and Yuanfeng respectively reached 89.34% and 100%. Both had avidity with the black walnut, respectively. And the new branches in 2004 were 0.40-1.75m long, and 3-11 shoots per tree. Meanwhile, the diameters of the branch base averagely reached to 0.65-2.3cm. The fruits per tree were 10 averagely in 2005.