A Study of Shoot Growth, Leaf Photosynthesis, and Nutrients in ‘Lingfengjing’ Litchi Grafted onto Seedlings of Different Cultivars

Abstract

Litchi (Litchi chinensis Sonn.) is one of the important fruit crops in southern China. ‘Lingfengnuo’ (LFN) is a new late-maturing litchi variety which has gained great popularity among consumers and growers due to its high quality and reliable productivity. However, there has been limited research on the graft compatibility of LFN on different rootstocks, which is important for selecting the optimal rootstocks for propagation, and thus application of this new cultivar. In this study, LFN scions were grafted onto one-year-old seedlings from 13 cultivars including ‘Heiye’ (HY), ‘Shakeng’ (SK), ‘Hehuadahongli’ (HHDHL), ‘Maguili’ (MGL), ‘Xiaojinzhong’ (XJZ), ‘Huaizhi’ (HZ), ‘Chenzi’ (CZ), ‘Shangshuhuai’ (SSH), ‘Baitangying’ (BTY), ‘Shuangjianyuhebao’ (SJYHB), ‘Jingganghongnuo’ (JGHN), ‘Baila’ (BL), and ‘Shuidong’ (SD). Graft success, morphology of the graft joint, shoot growth, leaf photosynthetic rate, and nutrients were compared. Graft success was highest for XJZ, HZ, BL and JGHN. Tree vigor, reflected by flush growth, was highest for HZ, followed by JGHN and BTY, but weakest for HY, SD, SJYHB, and XJZ. The stem significantly swelled above the graft joint in trees with rootstocks of HY, SD, and SJYHB seedlings; however, this did not occur in XJZ. Leaf photosynthesis displayed a similar pattern to tree vigor, and was highest for HZ and lowest for HY, SD, and XJZ. These low vigor trees produced flowers the next year after grafting. The result suggested that HZ, JGHN, and BTY seedlings as rootstock are highly compatible with LFN, while those of HY, SD, and SJYHB are poorly compatible. Rootstocks did not significantly influence the leaf N, P, and Fe, but showed significant differences in other minerals. The leaf Ca, Mg, Zn and B were lowest in the trees graft onto HZ seedlings. Based on these results, HZ seedlings are recommended as the best rootstock for the propagation of LFN; however, a supply of Ca, Mg, B and Zn fertilizers a especially needed for LFN trees on HZ seedling rootstock.