The similarity or differences of peroxidase isozymes in rootstocks and scions may influence their graft compatibility. This study was conducted to identify peroxidase isozymes that may be used as markers to predict compatibility between pear (Pyrus communis L.) and various quince (Cydonia oblonga Mill.) clones. `Bartlett' (BT) and `Beurre Hardy' (BH) pear cultivars are known to form incompatible and compatible grafts, respectively, with quince rootstocks. The two pear scion cultivars were budded on `quince A' (QA), `quince BA-29', and 15 selected quince clones from Turkey. Bark and cambial tissues were taken from nonbudded rootstocks and scions, and 4 cm above and below the graft union for peroxidase isozyme analysis performed by starch gel electrophoresis. Isoperoxidase analyses were also performed on samples from the graft unions collected 12 months after grafting. Many isozyme bands were observed commonly in the two scions; however, one anodal peroxidase A was detected in BH (compatible scion) but not in BT (incompatible scion) samples. This isoperoxidase was also detected in QA, Quince BA-29, and nine of the Turkish quince clones. Another isoperoxidase, band B, was detected in BH but not in BT or any of the rootstocks. However, the compatible (BH/QA) and moderately compatible (BT/BA-29) graft union tissues contained bands A and B whereas incompatible graft union tissues (BT/QA) lacked both. Graft union samples involving BT and five Turkish quince clones (705, 609-2, 702, 804, and 806) had both `A' and `B' isoperoxidases while one or both of these bands were absent in nonbudded graft partners. Field observations of 3.5 year-old grafts of BT and Turkish quince clones revealed that the vegetative growth (vigor) of BT scion was significantly greater, when grafted on these five clones, than that in graft combinations with other clones. We suggest that matching of isoperoxidase `A' in quince rootstocks and BH pear scion may be associated with a compatible graft combination. Additionally, presence of isoperoxidases `A' and `B' in the graft union tissues may be used as an indicator to predict a compatible graft between BT and quince rootstocks.
Hatice Gulen, Rajeev Arora, Ali Kuden, Stephen L. Krebs, and Joseph Postman
Loren C. Stephens
strong. One reason for trait variability in seed-produced cultivars could be the inbreeding barriers that exist in Echinacea germplasm ( Ault, 2006 ). Although poorly understood in Echinacea , one such barrier is assumed to be self-incompatibility (SI
Qing Xu, Shi-Rong Guo, He Li, Nan-Shan Du, Sheng Shu, and Jin Sun
species or genera, a lack of affinity, known as graft incompatibility, may occur. Graft incompatibility can induce undergrowth or overgrowth of the scion, which can lead to decreased levels of water and nutrients flowing through the graft union, causing
Júlia Halász, Attila Hegedűs, Zoltán Szabó, József Nyéki, and Andrzej Pedryc
Self-incompatibility in the Rosaceae L. family is of the gametophytic type based on pistil S -ribonucleases ( S -RNases) controlled by the highly polymorphic S -locus ( de Nettancourt, 2001 ). If two different cultivars share identical S
Shawn A. Mehlenbacher
Incompatibility in hazelnut (Corylus avellana L.) is of the sporophytic type and is under the control of a single S-locus with multiple alleles. Tests in recent years have identified four new alleles, bringing the total to 26. Improved pollen testers have been identified for several alleles. The S-alleles of more than 90 cultivars have been identified by fluorescence microscopy and will be presented. These cultivars (and their alleles) include Tonda di Giffoni (2 23), San Giovanni (2 8), Gasaway (3 26), Gunslebert (5 23), Kadetten (20 25), Lang Tidlig Zeller (4 20), Nocciolino Sangrato (7 17), Rode Zeller (6 11), Segorbe (9 23), and Simon (6 22).
Olfa Zarrouk, Pilar S. Testillano, María Carmen Risueño, María Ángeles Moreno, and Yolanda Gogorcena
, many peach cultivars exhibit graft incompatibility when grafted onto some plum rootstocks ( Moreno et al., 1994a ; Zarrouk et al., 2006 ). Manifestations of peach/plum incompatibility appear generally during the first summer after grafting, although
Javier Sanzol and Maria Herrero
adequate cropping ( Waite, 1894 ). Self-fertilization in pear is prevented by a gametophytic self-incompatibility system ( de Nettancourt, 2001 ) and pear cultivars are generally considered self-incompatible ( Crane and Lewis, 1942 ; Sanzol and Herrero
Sandra M. Reed
Low seed set has been reported following self-pollinations of flowering dogwood (Cornus florida L.). The objective of this study was to verify the presence of self-incompatibility in C. florida. `Cherokee Princess' stigmas and styles were collected 1, 2, 4, 8, 12, 24, 48, and 72 hours after cross- and self-pollinations, stained with aniline blue and observed using a fluorescence microscope. Pollen germinated freely following self-pollinations, but self-pollen tubes grew slower than those resulting from cross-pollinations. By 48 hours after cross-pollination, pollen tubes had reached the bottom of the style while pollen tubes in self-pollinated flowers had only penetrated the upper third of the style. Evidence of reduced pollen tube growth rate in self-pollinations of `Cherokee Chief' and `Cherokee Brave' was also obtained. This study provides evidence of a gametophytic self-incompatibity system in C. florida. It was also determined that stigmas of C. florida `Cherokee Princess' are receptive to pollen from 1 day prior to anthesis to 1 day after anthesis.
Yiran Li, Asuka Uchida, Akiha Abe, Akihiro Yamamoto, Tomonari Hirano, and Hisato Kunitake
Self-incompatibility is a genetic mechanism that exists in flowering plants to prevent a plant from being pollinated by its own pollen and to promote cross-pollination. Gametophytic SI (GSI), one form of SI, has been extensively studied and S
Shawn A. Mehlenbacher
one production zone to another, contrasts sharply with the situation with the major food crops. Pollen–stigma incompatibility in hazelnut is of the sporophytic type and controlled by a single locus, designated the S-locus, with multiple alleles