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Fruit trees are often planted in single-cultivar blocks that allow convenient orchard management. This planting design can reduce the opportunities for cross-pollination, decreasing fruit quality if many harvested fruit result from selfing rather than outcrossing. We aimed to: (1) identify flower visitors in a lychee orchard; (2) determine levels of selfing and outcrossing among two lychee cultivars (Kaimana and Kwai Mai Pink) at increasing distances from another cultivar in single-cultivar blocks; and (3) assess effects of pollen parentage on fruit size, skin colour, Brix, acidity, and mineral nutrient concentrations. The European honeybee and a rhiniid fly, Stomorhina discolor , were the most abundant flower visitors. Pollinators appeared to transport cross-pollen at similar levels among the different rows within the single-cultivar blocks. Kaimana trees produced a mixture of selfed and outcrossed fruit. Kwai Mai Pink trees produced more selfed fruit, with at least 75 % being self-fertilised and 19 % being cross-fertilised. Cross-pollination of Kaimana by Souey Tung or Fay Zee Siu increased fruit flesh mass by 27 % and 26 % compared with self-pollinated fruit, respectively, and whole-fruit mass by 20 % and 21 %, respectively. Cross-pollination of Kaimana by Souey Tung also provided the fruit with a small seed and a redder skin. Cross-pollination of Kwai Mai Pink by Wai Chee did not affect the fruit mass or colour compared with self-pollinated fruit. Cross-pollination did not significantly affect Brix, acidity, or mineral nutrient concentrations of Kaimana or Kwai Mai Pink fruit. The results demonstrate that these cultivars have a mixed mating system and that flower visitors transport cross-pollen across many orchard rows. The results also indicate that strategic selection and planting of polliniser cultivars, that provide an optimal pollen genotype, could lead to the production of heavier lychee fruit with improved skin colour and seed size. [ABSTRACT FROM AUTHOR]

Molecular tools were largely used to characterise native almond (Prunus dulcis Mill.) cultivars, to elucidate their diversification and to establish their membership to Mediterranean germplasm pools. Hereby, the efficiency of the application of PCR techniques to study the genetic diversity of S alleles in almond was tested to identify self-incompatible cultivar combinations and groups. Hence, an analysis with consensus AS1II and AmyC5R and with allele-specific primers was performed for 25 almond accessions including 17 local Tunisian cultivars, 7 advanced selections, and 1 extra group from Italy in order to identify their S-genotype. Interestingly, all genotypes were assigned to their specific self-incompatible groups and a new group (LI) has been established. The two cultivars 'Dillou' and 'Porto' both considered as self-compatible have been demonstrated to be self-incompatible. Results reveal also a discrepancy for the S-genotype assigned to 'Zahaaf' preserved in the International almond collection. Thus, S genes genotyping of commercially used or newly released cultivars is very useful as we demonstrated that it may show that common knowledge may be partly inaccurate. For important varieties, this immediately has a consequence for cultivation practices, also for smallholder orchards as changing an incorrect practice may in time increase yield and also guarantee yield stability. [ABSTRACT FROM AUTHOR]

Recognition of self-incompatibility (SI) is regulated by the SRK and SP11 genes in Brassicaceae. Brassica rapa and B. oleracea are self-incompatible, while most cultivated species of B. napus, which arose from hybridization between B. rapa and B. oleracea, are self-compatible. Various studies of the SRK and SP11 genes in self-compatible B. napus have been reported, but details of the mechanism in different B. napus lines are not fully understood. In this study, we confirmed the S haplotypes, SI phenotypes and SP11 expression in 10 representative lines of B. napus, and identified two SI lines (N110 and N343) lacking SP11 expression. In N343 (with BnS1 and BnS6 haplotypes), we confirmed that there is a 3.6-kb insertion in the promoter region of BnSP11-1, and that BnSP11-1 and BnSP11-6 are not expressed, as reported previously (expression of BnSP11-6 is suppressed by the BnS1 haplotype), although this line is self-incompatible. Similarly, in N110, with two novel S haplotypes (BnS8 and BnS9) in addition to BnS6, a 4.3-kb insertion was identified in the promoter region of BnSP11-9, and expression levels of BnSP11-6, BnSP11-8 and BnSP11-9 were all suppressed (BnSP11-6 and BnSP11-8 may be suppressed by BnS8 and BnS9, respectively), although the phenotype was selfincompatible. This observation of an SI phenotype without SP11 expression suggests the existence of unknown factor(s) that induce pollen-stigma incompatibility in B. napus. [ABSTRACT FROM AUTHOR]

Self-incompatibility (SI) is a sophisticated system for pollen selectivity to prevent pollination by genetically identical pollen. In Brassica, it is genetically controlled by a single, highly polymorphic S-locus, and the male and female S-determinant factors have been identified as S-locus protein 11 (SP11)/S-locus cysteine-rich protein (SCR) and S-locus receptor kinase (SRK), respectively. However, the overall molecular system and identity of factors in the downstream cascade of the SI reaction remain unclear. Previously, we identified a self-compatible B. rapa mutant line, TSC28, which has a disruption in an unidentified novel factor of the SI signaling cascade. Here, in a genetic analysis of TSC28, using an F2 population from a cross with the reference B. rapa SI line Chiifu-401, the causal gene was mapped to a genetic region of DNA containing markers BrSA64 and ACMP297 in B. rapa chromosome A1. By fine mapping using an F2 population of 1,034 plants, it was narrowed down to a genetic region between DNA markers ACMP297 and BrgMS4028, with physical length approximately 1.01 Mbp. In this genomic region, 113 genes are known to be located and, among these, we identified 55 genes that were expressed in the papilla cells. These are candidates for the gene responsible for the disruption of SI in TSC28. This list of candidate genes will contribute to the discovery of a novel downstream factor in the SP11-SRK signaling cascade in the Brassica SI system. [ABSTRACT FROM AUTHOR]

The development of hermaphrodite cultivars of kiwifruit (Actinidia deliciosa) to overcome dioecism is a priority for all breeding programmes, worldwide. If successful, the number of pollinators in the orchard could be reduced, allowing more space for reproductive vines. Hermaphroditism and the expression of self-compatibility were studied in A. deliciosa, using the new kiwifruit cultivar, 'Tsechelidis', as a model. This plant material was chosen for investigation as its female flowers produced viable pollen. The aim of the present study was to investigate the expression and nature of self-compatibility in 'Tsechelidis' and to evaluate its potential for breeding purposes. The expression of self-compatibility in 'Tsechelidis', between years, was investigated by controlled self-pollination of female flowers in the field and by microscopic studies on pollen viability in the laboratory. The commercial cultivar 'Hayward' and the pollinator 'Matua' were used as controls. Controlled self-pollination in the field confirmed that 'Tsechelidis' exhibited a degree of hermaphroditism and selfcompatibility. Its flowers produced viable pollen and could set fruit of an acceptable size and quality after self-pollination, compared to open-pollinated fruit. The average fruit set percentage for 'Tsechelidis' was 34%, and ranked from 20% to 60% per vine, while the corresponding rate for 'Hayward' was only 4%. Microscopic studies on 'Tsechelidis' pollen revealed variations in pollen viability between different vines, which were even greater between different flowers on the same vine, ranging, in some cases, from 0% (absolutely sterile) to 70% (significantly fertile) per flower. Female control 'Hayward' vines were found to be practically sterile (0%), while male control 'Matua' vines were almost 100% fertile. The nature of self-compatibility in 'Tsechelidis' was investigated further by molecular analysis using the sex-linked sequence characterised amplified region (SCAR) markers, SmX, SmY, and SmY1, and by single nucleotide polymorphism (SNP) analysis. Hermaphroditism in 'Tsechelidis' was related to sex expression, as observed by SNP analysis, but complete genome mapping would be required to fully understand the mechanisms involved and to exploit this new genetic material for breeding purposes. [ABSTRACT FROM AUTHOR]

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Coffea anthonyi Stoff. & F. Anthony from Cameroon and the Republic of Congo is formally described. Morphological, biochemical and molecular characteristics, isozyme diversity and phylogenetic relationships are discussed. The new diploid species has strong relationships with the East African C. eugenioides and the allotetraploid cultivated C. arabica. As such, it could be related to a progenitor species of C. arabica. The new species is self-compatible, being a rare character within the genus Coffea. This new small-leaved Central African species is of particular interest from a phylogenetic as well as from a breeding point of view. [ABSTRACT FROM AUTHOR]