bioRxiv Science⌕ Search
Home/Archive/bioRxiv

bioRxiv · 10.1101/2021.05.23.445304

Study of compatibility and determination of the suitable pollinizer for Argane tree (Argania spinosa L.)

Ait Aabd, N.·Tahiri, A.·Mimouni, A.·Bouharroud, R.
View original source ↗Export metadata ↓

Abstract

During the breeding program studies, the pollen donor parents (pollinizers) were observed to be characterized by a strong flowering rate and very low fruit set, even after hand pollination. Then the notion of pollinizers in the argane species was born, first mentioned, checked, documented and confirmed like other conventional tree species. Since the argane tree is completely self-incompatible, the presence of compatible pollinizers is necessary for the fruit set. Indeed, pollinizers need to be selected accurately based on the synchronization of bloom periods and compatibility to receiver trees (female). The pollinizer is essential in any breeding program and for new orchard plantations. The current study was conducted on 13 argane genotypes including two pollinizers. The flowering period, bloom phenology, floral structure and fruit set of crossed genotypes were monitored, illustrated and a season phenogram was established. The pollen viability and germination were also evaluated. In order to test compatibility, the hand pollination using two selected pollinizer pollens was compared to open pollination. Then, the compatibility system was monitored and evaluated through analysis of crossing diallel programs and through the index of self-incompatibility. The flowering periods are genotype depending and one to three blooms have been observed during the two years study (2018-2019) and the argane tree is a tristylous species (Mesostylous, brevistylous and longistylous flowers). The in vitro tests showed that the pollen originated from crossed genotypes were viable and able to germinate. The cross-compatibility rate depends on cross associations and it varies from 39 to 84 %. In fact, this study showed that the effect of pollen-parent (xenia) occurs in all fruit components of argane tree. It was observed, for the first time, that both compatible pollinizers and xenic effects of pollen on argane fruit have occurred. Artificial pollination is currently feasible for breeding programs and the screening of elite genotypes. Then the selected pollinizer is quite required for the development of argane tree cropping. HighlightsO_LIPollinizers in the argane species first mentioned C_LIO_LIPollinizer is essential in any breeding program and for new orchard plantations C_LIO_LIArgane tree is self-incompatible C_LIO_LIPollen-parent effect, (xenia) occurs in all fruit components of argane tree C_LI

Explore related subjects

plant biologyPreprint

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Ait Aabd, N., Tahiri, A., Mimouni, A., Bouharroud, R.. 2021-05-23. Study of compatibility and determination of the suitable pollinizer for Argane tree (Argania spinosa L.). https://doi.org/10.1101/2021.05.23.445304

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related preprints

bioRxiv2026

Ancestral polyploidy and non-linear dosage shifts define the photosynthetic transition in the Heliantheae alliance

Whole-genome duplications (WGDs) have played a central role in plant evolutionary innovation, yet their genome-wide influence on complex physiological traits such as carbon-concentrating mechanisms (CCMs) remains poorly resolved. Here, we present high-quality genome assemblies and annotations for 35 species within the Heliantheae alliance (Asteraceae), spanning the complex photosynthetic spectrum from C3 to C4. Ks-based analyses combined with gene tree-species tree reconciliation identified a shared paleopolyploid event (WGD-2) ~30 million years ago. Using phylogenetically informed association mapping with these species, we detected 451 functional MapMan BINs with copy number variation significantly associated with interspecific variation in the CO2 compensation point. Notably, 303 of these BINs contain greater than 10% WGD-2-derived genes, indicating a strong enrichment of duplicated loci within photosynthetically relevant functional modules. Effect-size analysis revealed that the C3-to-C4 transition is governed by threshold-dependent genomic architecture rather than gradual additive change. Substantial expansions in key transcription factor modules, including HD-ZIP, HSF, LOB, and TCP, were associated with strong non-linear physiological shifts, consistent with genomic tipping points. By integrating comparative genomics, physiological trait variation, and evolutionary analysis, this study establishes a mechanistic link between ancient polyploidy and contemporary photosynthetic diversification. These findings provide a framework for understanding the genetic basis of carbon concentrating mechanism evolution and inform future optimization of photosynthetic efficiency in Asteraceae crops such as sunflower.

plant biology↗
bioRxiv2026

Heat-induced increases in xylem vulnerability: Experimental evidence and possible mechanisms

Hotter droughts driven by global warming are increasing tree mortality worldwide. Here, we propose a theoretical framework that explains how dissolved gas affects the stability of bubbles in xylem sap, and shows that in the presence of gas, sudden increases in temperature can accelerate embolism formation. We then provide experimental evidence that heat exposure can change xylem vulnerability to drought. Using data from seven Australian and European tree species, we assessed how elevated temperature (+15 and +20 {degrees}C above ambient) affects both xylem embolism resistance, measured with the Optical Vulnerability Technique, and VPD-corrected drying times. We found evidence for reduced embolism resistance and accelerated dehydration in heat-exposed plants. On average, trees reached the water potential at 50% loss of xylem function at 0.73 MPa less negative water potentials and 7.8 kPa h earlier, though responses were highly species-specific, and credibly different from zero only in the Australian species. Our results are consistent with the proposed framework and suggest that embolism resistance may not be a static trait, which has important repercussions for studies of plant vulnerability to drought. Further studies are necessary to assess the potential effects of heat-induced reductions in embolism resistance on tree mortality during heatwaves.

plant biology↗
bioRxiv2026

Genome-wide latitudinal variation associated with defence and reproductive pathways linked to Norway spruce adaptation

Environmental cues modulate the natural variations in genes that outline local adaptation in plants for optimal survival. Genome-wide analysis using exome capture dataset in Norway spruce (Picea abies L. Kast) in Sweden revealed natural allelic variation in coding regions of genes associated with defence and reproductive pathways that follow a latitudinal cline, despite of the weak population structure with a low genetic differentiation. Steepest clines in the allele frequencies of missense SNPs from coding region (cSNPs) were detected in 60S RIBOSOMAL PROTEIN L18 (RPL18C), a gene involved in plant survival and defence/stress responses and LONG AFTER FAR-RED 3 (LAF3) that mediates light responses. This was closely followed by cline in ZINC 4 FINGER DNA 3'-PHOSPHOESTERASE (ZDP), involved in DNA repair and DNA demethylation pathways. Flowering genes that displayed latitudinal cline in cSNPs included BARELY ANY MERISTEM 1 (BAM1), REDUCED VERNALIZATION RESPONSE 1 (VRN1), FLOWERING CONTROL LOCUS A (FCA) and TERMINAL FLOWER 1 (TFL1) among few others. These variations may contribute to differential functioning of the defence/flowering genes, enabling the tree to thrive at its best under given local environmental conditions. The clines provide evidence towards local adaptation in these Norway spruce populations across Sweden; it coincides with the latitudinal variation in climatic conditions including temperature, day length and light quality, along with existing cline e.g. differential growth and defence response, and bud-burst/bud-set. The knowledge can be applied in forest industry to design future sustainable breeding strategies e.g. assisted migration, in the context of inevitable climate change.

plant biology↗