Peroxidase activity and initial growth of ‘Barbosa’ peach on clonal rootstocks

Abstract In the peach nursery trees production, the use of rootstocks with unknown genetic identity obtained from peach seeds in the canning industry is frequent. The hypothesis tested was that there are rootstocks that express greater graft compatibility, enabling greater survival and growth, and that peroxidase activity can be used as indication of graft incompatibility. The aim of this study was to evaluate the survival and the peroxidase activity efficiency in identifying graft incompatibility and the trunk diameter growth of ‘Barbosa’ peach grafted onto 18 Prunus clonal rootstocks, propagated by herbaceous cuttings, compared to own-rooted scion trees. The experimental design was three randomized blocks, with one tree per plot. The first three vegetative cycles of trees conducted in double Y (5.0m x 2.0m) without irrigation were evaluated. The highest trunk diameter growth was provided by ‘Okinawa’, ‘Tsukuba-1’, ‘Tsukuba-2’, Mexico F1 and ‘Flordaguard’ rootstocks, without differing from own-rooted ‘Barbosa’ peach. Peroxidase activity differs by rootstock effect at the beginning of the dormancy period, and is higher than in vegetative growth, especially in interspecific graft combinations. Peroxidase activity is a biochemical indicator of stress, but should not be used alone and generalized to characterize graft incompatibility.

摘要：在桃树育苗生产中，使用罐头工业来源的桃种子繁育、遗传身份不明的砧木是较为普遍的做法。本研究检验的假设为：存在嫁接亲和性更强的砧木，可实现更高的成活率与生长表现，且过氧化物酶(peroxidase)活性可作为嫁接不亲和性的指示指标。本研究旨在评估‘巴尔博萨’(Barbosa)桃接穗嫁接于18种通过草本扦插繁殖的李属(Prunus)无性系砧木后的成活率、过氧化物酶活性在鉴定嫁接不亲和性中的应用效能，以及树干直径生长情况，并以自根‘巴尔博萨’桃树作为对照。试验采用完全随机区组设计，设置3次重复，每小区1株树。试验评估了无灌溉条件下采用双Y型整形（株行距5.0m×2.0m）的前3个营养生长周期的桃树生长情况。‘冲绳’(Okinawa)、‘筑波-1’(Tsukuba-1)、‘筑波-2’(Tsukuba-2)、墨西哥F1(Mexico F1)以及‘弗洛达加德’(Flordaguard)砧木可实现最高的树干直径生长，其表现与自根‘巴尔博萨’桃树无显著差异。在休眠期初期，过氧化物酶活性因砧木效应存在显著差异，且显著高于营养生长期，尤其是在种间嫁接组合中。过氧化物酶活性是一种胁迫生化指标，但不应单独使用或泛化用于表征嫁接不亲和性。