Bisognin C, Schneider B, Salm H, Grando M S, Jarausch W, Moll E, Seemüller E
IASMA Research Center, San Michele all'Adige TN, Italy.
Phytopathology. 2008 Feb;98(2):153-8. doi: 10.1094/PHYTO-98-2-0153.
In an effort to select and characterize apple rootstock resistant to apple proliferation (AP), progenies from seven apomictic rootstock selections and their parental apomictic species, Malus sieboldii and M. sargentii, were compared to standard stocks M 9 and M 11. Seedlings derived from open pollinated mother plants were grafted with cv. Golden Delicious and grown under natural infection conditions. The progenies differed greatly in resistance to the AP agent 'Candidatus Phytoplasma mali'. Progenies of M. sieboldii and its descendent rootstock selections D2212, 4608, 4551, and D1131 showed a high level of resistance, whereas progenies of M. sargentii and its descendent selections D1111 and C1828 proved susceptible. M 9 and M 11 showed an intermediate level of resistance. Phytoplasma titer in roots of the M. sieboldii and M. sargentii progeny groups was similarly low, whereas the concentration in the standard stocks was 100 to 5,000 times higher. In trees on most of the resistant stocks, only a minority was colonized in the scion, while in trees on susceptible and standard stocks, infection rate was often higher. Also, the titer in the top of trees on resistant stocks was usually lower than in trees on susceptible and standard stocks. Four progenies derived from open pollinated M. sieboldii and M. sieboldii descendents were subjected to DNA typing using simple sequence repeat (SSR) markers. This study revealed that the selected groups consisted mainly of mother-like plants (apomicts) and type I hybrids (unreduced mother genotype plus one male allele at each locus). Type II hybrids (full recombinants) and autopollinated offspring were rare. In the 4608 progeny, trees grown on type I hybrid rootstocks were significantly less affected than trees on mother-like stocks. In other progenies with fewer or no type I hybrids, trees on type II hybrids and autopollinated offspring suffered considerably more from disease than trees on mother-like stocks.
为了筛选和鉴定抗苹果增殖病（AP）的苹果砧木，将7个无融合生殖砧木选系及其亲本无融合生殖种山荆子（Malus sieboldii）和毛山荆子（M. sargentii）的后代与标准砧木M 9和M 11进行了比较。从自由授粉的母株上获得的实生苗嫁接金冠品种，并在自然感染条件下生长。这些后代对苹果增殖病病原体‘苹果植原体（Candidatus Phytoplasma mali）’的抗性差异很大。山荆子及其后代砧木选系D2212、4608、4551和D1131的后代表现出高度抗性，而毛山荆子及其后代选系D1111和C1828的后代则被证明易感。M 9和M 11表现出中等抗性水平。山荆子和毛山荆子后代组根系中的植原体滴度同样较低，而标准砧木中的浓度则高出100至5000倍。在大多数抗性砧木的树上，只有少数接穗被侵染，而在易感砧木和标准砧木的树上，感染率通常更高。此外，抗性砧木树上树顶的滴度通常低于易感砧木和标准砧木的树。对从自由授粉的山荆子及其后代中获得的4个后代进行了简单序列重复（SSR）标记的DNA分型。这项研究表明，所选群体主要由类母本植株（无融合生殖体）和I型杂种（每个位点上未减数的母本基因型加一个父本等位基因）组成。II型杂种（完全重组体）和自花授粉后代很少见。在4608后代中，生长在I型杂种砧木上的树比生长在类母本砧木上的树受影响明显更小。在其他I型杂种较少或没有I型杂种的后代中，生长在II型杂种和自花授粉后代上的树比生长在类母本砧木上的树患病严重得多。
