Biology subjects

Abbo, S.

Publications and source records attributed to Abbo, S..

4 recordsLinked to original sources

bioRxiv2023

Optimization of chickpea irrigation in a semi-arid climate based on morpho-physiological parameters

While the world population is steadily growing, the demand for plant-based protein in general, and chickpea in particular, is rising. Heatwaves and terminal drought are the main environmental constraints on chickpea production worldwide. Thus, developing better irrigation management for the chickpea agro-system can promote higher and more sustainable yields. Supplemental irrigation at the right timing and dose can increase yield dramatically. Here, we studied the response of a modern Kabuli chickpea cultivar to supplemental irrigation during the critical pod-filling period over three growing seasons (2019-2021) in northern Negev, Israel, under semi-arid conditions. Six irrigation treatments were applied based on irrigation factors of 0, 0.5, 0.7, 1.0, 1.2, and 1.4 of crop evapotranspiration (ET0) as measured by an on-site meteorological station. Morpho-physiological parameters and above-ground biomass accumulation were monitored throughout the cropping seasons, and the final grain yield was determined at maturation. Irrigation onset was determined based on plants leaf water potential ({Psi}LWP > 15 bar) in the field. Our results indicate that optimal water status (as reflected by pressure chamber values) was 12-14 bar during the irrigation period. Irrigation according to evapotranspiration (ET0) with an irrigation factor of 1.2 resulted in the highest grain yields over the three years. To ensure optimal water supply during the reproductive phase compatible with the crop water requirements, maintaining a 25 mm node length above the last fully developed pod and a 90 mm distance between the last fully developed pod to the stem apex is recommended. In conclusion, irrigation onset when the crop is already at mild drought stress, followed by sufficient irrigation while following the indicated morphology and water potential values, may help farmers optimize irrigation and maximize chickpea crop production. HighlightsO_LIChickpea irrigation is optimized based on meteorological data (ETc) and morphological traits. C_LIO_LIMorphological- not only physiological- traits can capture the dynamics of crop water status. C_LIO_LIIrrigation onset should be at mild drought stress (>15 bar) during the reproductive stage. C_LIO_LIExtending the reproductive phase is essential for grain yield improvement under semi-arid conditions. C_LIO_LIIF=1.2 provides the most productive irrigation regime for chickpea in Mediterranean conditions. C_LI

plant biology↗

bioRxiv2023

Pre-anthesis spike growth dynamics and its association to yield components among elite bread wheat cultivars (Triticum aestivum L. spp.) under Mediterranean climate

Wheat (Triticum spp.) grain yield (GY) is highly associated with grain number per unit area (GN m-2). Biomass accumulation and partitioning are essential to understand pre-anthesis spike growth dynamics which determines spike dry matter at anthesis (SDMa) - a GN determinant. Spike growth takes place during the stem elongation period (SE), from terminal spikelet to anthesis, following leaf and spikelet initiation (LS) from sowing to terminal spikelet. In this study, bread wheat cultivars were examined under Mediterranean semi-arid conditions to determine (i) the varietal differences in pre-anthesis phase duration, (ii) whether this variability influences biomass partitioning and spike-related traits, and (iii) to what extent, the genotypic variations in pre-anthesis phase duration and spike growth are associated with yield components. A panel of Israeli commercial bread wheat cultivars were grown in the field during 2016-17 (three environments) and 2017-18 (two environments) and characterized for pre-anthesis phases, floral conditions and spike fertility via histological measurements, spike traits and dry matter accumulation and partitioning at anthesis and maturity and for yield components. Significant variability in the timing of pre-anthesis phases was detected within the tested panel. LS duration, and occasionally SE, favourably related with a better dry matter of fertile florets spike-1 (at anthesis) and SDM (at both anthesis and maturity). Two cultivar pairs Zahir-Yuval and Negev-Gedera, which flowered concurrently, revealed significant differences in the durations of LS and SE phases across the environments. Longer LS (e.g., in cultivars Zahir and Negev) exhibited increased spikelets number spike-1, whereas longer SE (e.g., in Yuval and Gedera) enhanced spike fertility through improving the survival rate of floret primordia (FSR%) of central spikelets. However, there was a trade-off for FSR at the proximal and distal spike portions, resulting reduction of final GN (or GY) in cultivars with longer SE. It is concluded that, in this panel, the duration of both LS and SE contribute to spike fertility. However, under short wheat growing cycle, LS duration seemed a stronger driver than SE for GN and yield enhancement. These highlights the novel importance of pre-anthesis phases, especially the role of LS in wheat yield increment during the short growing cycle. The varietal combination with variable LS and SE duration could be implemented in the breeding pipeline and used as pre-breeding materials for GN improvement. Furthermore, the findings will improve pre-anthesis traits adoption in Mediterranean bread wheat future breeding programs.

plant biology↗

bioRxiv2021

Drivers of genetic differentiation and recent evolutionary history of an Eurasian wild pea

Genetic diversity a major determinant for the capacity of species to persist and adapt to their environments. Unraveling the factors affecting genetic differentiation is crucial to understand how genetic diversity is shaped and species may react to changing environments. We employed genotyping by sequencing to test the influence of climate, space, latitude, altitude and land cover on genetic differentiation in a collection of 81 wild pea samples (Pisum sativum ssp. elatius) from across its distribution range from western Europe to central Asia. We also attempted to elucidate the species recent evolutionary history and its effect on the current distribution of genetic diversity. Association of single SNPs with climate variables were analyses to test for signatures of local adaptation. Genetic variation was geographically structured into six distinct genetic cluster. Two of which were associated with a taxonomic group (Pisum sativum ssp. humile) that according to some researchers does not qualify for a sub-species rank due to its alleged lack of genetic distinctness from other conspecific groups. The effect of the tested factors influencing genetic differentiation were rather variable among genetic clusters. The climate predictors were most important in all clusters. Land use was more important in clusters from areas strongly influenced by human land use, especially by agriculture. We found a statistically significant association of 3,623 SNPs (2.4 % of all SNPs) with one of the environmental predictors. Most of them were correlated with latitude followed by temperature, precipitation and altitude. Estimation of SNP effects of the candidates resulted in a missense to silent ratio of 0.45, suggesting many of the observed candidates SNPs may alter the encoded amino acid sequence. Wild peas went through a genetic bottleneck during the last glacial period followed by population recovery. Probably associated with this population recovery, we detected a range expansion, which may have led to an eastward range expansion of the European cluster to Turkey and thereof southwards and eastwards. Overall, the interplay of several environmental factors and the recent evolutionary history affected the distribution of genetic diversity in wild peas where each subpopulations were differently affected by those factors and processes.

evolutionary biology↗

bioRxiv2021

Identification of a Major Locus for Flowering Pattern Sheds Light on Plant Architecture Diversification in Cultivated Peanut

Flowering pattern is a major taxonomic characteristic differentiating the two main subspecies of cultivated peanut (Arachis hypogaea L.). subsp. fastigiata possessing flowers on the mainstem (MSF) and a sequential flowering pattern, whereas subsp. hypogaea lacks flowers on the mainstem and exhibits an alternate flowering pattern. This character is considered the main contributor to plant architecture and the adaptability of each subgroup to specific growing conditions. Evidence indicates that flowering pattern differentiation occurred during the several thousand years of domestication and diversification in South America. However, the exact genetic mechanism that controls flowering pattern and the molecular changes that led to its historical diversification in peanut are unknown. We investigated the genetics of the flowering pattern in a recombinant inbred population of 259 lines (RILs), derivatives of an A. hypogaea and A. fastigiata cross. RILs segregated 1:1 in both the sequential/alternative and the MSF-plus/MSF-minus traits, indicating a single gene effect. Using the Axiom_Arachis2 SNP-array, MSF was mapped to a 1.7 Mbp segment on chromosome B02 of the cultivated A. hypogaea. Significant haplotype conservation was found for this locus in the USA peanut mini core collection, suggesting a possible selection upon hypogaea/fastigiata speciation. Furthermore, a candidate Terminal Flowering 1-like (AhTFL1) gene was identified within the MSF region, in which a 1492 bp deletion occurred in the fastigiata line that leads to a truncated protein product. Remapping MSF in the RIL population with the AhTFL1 deletion as a marker increased the LOD score from 53.3 to 158.8 with no recombination. The same deletion was also found to co-segregate with the phenotype in two EMS-mutagenized M2 families, suggesting a hotspot for large mutational deletion or gene conversion that may play a role in evolution. BLASTX analysis showed that the most similar homologous gene for TFL1-like in soybean is Det1, which previously was shown to control shoot determination. Sequence analysis of the TFL-1 in a series of domesticated lines showed that TFL1 was subjected to gain/loss events of the deletion, partly explaining the evolution of MSF in Arachis. Altogether, these results support the role of AhTFL-1 in peanut speciation during domestication and modern cultivation.

genetics↗