it. ‘Hi-Test’ is a self-compatible, inbred cultivar that yields high-quality, uniform seed, containing high levels of the glucosinolate glucoraphanin (GR). This variety has very uniform growth characteristics, plant size, seed yield, and chemical
Ossama Kodad and Rafel Socias i Company
Most almond breeding programs have fostered the development of self-compatible cultivars to overcome the problems related to cross-pollination of this mostly self-incompatible species ( Socias i Company, 2002 ). Consequently, self
Shawn A. Mehlenbacher and David C. Smith
The cutleaf hazelnut [Corylus avellana L. f. heterophylla (Loud.) Rehder] is an ornamental form with strongly dissected leaf morphology. Its stigmas express incompatibility allele S20 but none of the other 25 S-alleles was detected with fluorescence microscopy. Three seedlings from a cross of the cutleaf hazelnut and VR6-28 lacked S20 and were investigated further. Each expressed an allele from the parent VR6-28 (S2 S26), S26 in OSU 562.031 and OSU 562.048 and S2 in OSU 562.049. S2 and S26 are low in the dominance hierarchy, so we expected the new allele from the cutleaf hazelnut to be expressed in their pollen. Unexpectedly, fluorescence microscopy showed that pollen of all three selections was compatible on their cutleaf parent and on each other, and furthermore, self-pollinations showed the excellent germination and long parallel tubes in the styles that are typical of a compatible pollination. Controlled self- and cross-pollinations in the field verified the self-compatibility of two selections. Cluster set for self-pollinations was very high (75-90%) and within the range observed for compatible cross-pollinations. Furthermore, the frequency of blank nuts was low (<10%). The second allele in the cutleaf hazelnut is designated S28, and its presence in seedlings of `Cutleaf' is indicated by the absence of S20. Controlled pollinations in the field also showed that selection OSU 562.069 (S2 S28) from the cross `Cutleaf' × `Redleaf #3' was self-compatible. Fluorescence microscopy showed that two additional seedlings were self-incompatible [OSU 367.052 (S1 S28) and OSU 367.076 (S6 S28)] while a third [OSU 706.071 (S9 S28)] was self-compatible. Self-compatibility may be limited to genotypes that combine S28 with a second allele that is low in the dominance hierarchy.
Ryan N. Contreras, John M. Ruter, and David A. Knauft
and also controls flower and petiole color. Test crosses and emasculation also suggested that all of the progeny produced in the current study developed through sexual hybridization and that all genotypes used in the study were self-compatible
Group-author : R. Socias i Company
Pollen tube growth was studied in 10 almond [Prunus amygdalus Batsch, syn. P. dulcis (Mill.) D.A. Webb] selections of the Zaragoza breeding program, whose main objective is the development of self-compatible cultivars. Self-compatibility was evident in eight of the selections, as indicated by the fact that pollen tube growth was similar following self- and cross-pollination. In the other two selections, pollen tube growth differed following self- and cross-pollination, one showing self-incompatibility and the other an irregular progression of crossed pollen tubes. The importance of the style in sustaining pollen tube growth was evident, and pollen tube growth was influenced by style type.
José Manuel Alonso and Rafael Socias i Company
Pollen tube growth after selfing was studied in four almond (Prunus amygdalus Batsch) families derived from crosses between self-compatible `Tuono' and self-incompatible `Ferragnès' and `Ferralise' in both directions, in order to ascertain the phenotypic expressions of the different genotypes. A differential expression of self-compatibility was observed in the seedlings of the different families. The genetic self-compatible offspring of `Ferralise' showed a lower percentage of pistils with pollen tubes at the style base and a lower number of pollen tubes at the pistil base after self-pollination than those observed in the self-compatible offspring of `Ferragnès'. This low level of self-compatibility expression observed in some `Ferralise' seedlings may be due to the inbreeding present in `Ferralise'. As a consequence, caution must be taken in almond breeding to avoid the increase of inbreeding by the utilization of related parents and to diversify the sources of self-compatibility, at present mostly limited to `Tuono.'
Mark W. Farnham and Howard F. Harrison
The discovery that broccoli (Brassicaoleracea L., Italica Group) sprouts contain high levels of sulforaphane, a constituent that may provide chemoprotection against certain carcinogens, has stimulated much interest in seed production of this crop. Studies were undertaken to determine the potential for producing broccoli seed using self-compatible selections from open-pollinated (OP) populations or doubled-haploid (DH) programs. In all outdoor and greenhouse trials, three OP selections and seven DH lines produced selfed seed, but seed weight per plant and number per plant varied significantly among the entries. In all environments there were individuals with relatively high (i.e., >3 g/plant) production that were significantly different from low (i.e., <2 g/plant) producers. The relative productivity of some lines varied greatly between experiments, which indicates that seed production of particular genotypes is affected differently by environmental conditions. This indicates the importance of identifying lines that are high producers of selfed seed across different environments. Two OP cultivar-derived lines (USVL102 and USVL104) and two DH lines (USVL062 and USVL093) were identified that consistently produced relatively high yields in greenhouse and screen cage trials. These lines are good candidates for evaluating seed production in field tests and as possible sources of seed for sprouting.
A. Godini, L. de Palma, and M. Palasciano
A study to ascertain the highest possible fruit set following self-pollination of eight self-compatible cultivars of almond (Amygdalus communis L. = Prunus dulcis Mill) was carried out in Apulia (southern Italy). Fruits set from daily hand-selling were high, compared to those from unassisted self-pollination. The results support growing most of the self-compatible Apulian almonds in solid blocks, without need for cross-pollination, provided that self-pollination is optimized by insect vectors. The relative capability of the cultivars to set fruits by unassisted self-pollination was independent of the reciprocal stigma/anthers position within the same flower.
Toshio Hanada, Kyoko Fukuta, Hisayo Yamane, Tomoya Esumi, Ryutaro Tao, Thomas M. Gradziel, Abhaya M. Dandekar, Ángel Fernández i Martí, José M. Alonso, and Rafel Socias i Company
locus gene are called pistil and pollen S alleles. Almond cultivars are largely self-incompatible (SI) ( Tufts and Philip, 1922 ), although self-compatible (SC) cultivars exist ( Socias i Company, 1990 ). Grasselly and Olivier (1976) reported that
Attila Hegedüs, Zoltán Szabó, József Nyéki, Júlia Halász, and Andrzej Pedryc
The most commercially grown peach [Prunus persica (L.) Batsch.] cultivars do not require cross-pollination for reasonable fruit set; however, self-incompatibility is a well-known feature within the Prunoideae subfamily. Isoelectric focusing and native polyacrylamide gel electrophoresis of S-ribonucleases; PCR analyses of S-RNase and S-haplotype-specific F-box genes as well as DNA sequencing were carried out to survey the self-(in)compatibility allele pool and to uncover the nature of self-compatibility in peach. From 25 cultivars and hybrids with considerable diversity in phenotype and origin, only two S-haplotypes were detected. Allele identity could be checked by exact length determination of the PCR-amplified fragments and/or partial sequencing of the peach S 1-, S 2-, and Prunus davidiana (Carr.) Franch. S 1-RNases. S-RNases of peach were detected to possess ribonuclease activity, and a single nucleotide polymorphism in the S 1-RNase was shown, which represents a synonymous substitution and does not change the amino acid present at the position in the protein. A 700-bp fragment of the peach SFB gene was PCR-amplified, which is similar to the fragment size of functional Prunus L. SFBs. All data obtained in this study may support the contribution of genes outside the S-locus to the self-compatible phenotype of peaches.