No abstract

Modern hexaploid wheat has several diploid and tetraploid predecessors. Morpho-physiological adaptation and the adaptation to drought of these different ploidy wheat species is largely unknown. To investigate the adaptation to drought stress, eight accesssions (two wild diploid (2n) accessions of Aegilops tauschii Coss., two domesticated diploid (2n) accessions of Triticum monococcum L., two domesticated tetraploid (4n) accessions of Triticum dicoccum Schrank ex Schübl. and two domesticated hexaploid (6n) accessions of Triticum aestivum L.) were exposed to three water regimes: (i) well-watered control (WW, 80% field capacity (FC)), (ii) moderate water stress (MS, 50% FC), and (iii) severe water stress (SS, 25% FC) from 30 days after sowing to maturity. The results showed that accession (A), water regime (W), and the interaction of A × W significantly affected yield, morpho-physiological traits, biochemical characteristics and biomass allocation. In the WW treatment, the aboveground biomass, ear biomass, grain yield and harvest index increased, whereas the number of spikes and spikelets per plant decreased from accessions of T. monococcum to T. dicoccum to T. aestivum. Across all accessions, yields decreased by 29% under moderate water stress and 61% under severe water stress. In all three water regimes, yields were positively correlated with photosynthesis (Pn) per plant (Pn × leaf area) at jointing and anthesis, largely the result of the differences and changes in leaf area. Water use efficiency for grain (WUEG) decreased by 2–6% in T. monococcum, but it increased by 15–16% in T. dicoccum and T. aestivum under drought stress. Analysis of the allometric relationships between aboveground biomass (MAB) and root biomass (Mroot) in the different species indicated that less biomass was allocated to roots with greater polyploidy while more biomass was allocated to roots with drought in A. tauschii, but not in the domesticated species. We conclude that domestication, selection and breeding of higher ploidy wheat has increased wheat yields primarily by increasing aboveground biomass and harvest index, increases that were maintained under water stress.

The present study aimed to evaluate the effect of Bacillus amyloliquefaciens and/or Arbuscular Mycorrhizal Fungi (AMF) as natural biofertilizers on biomass, yield, and seed nutritive quality of soybean (Giza 111). The conditions investigated include a well-watered (WW) control and irrigation withholding at the seed development stage (R5, after 90 days from sowing) (DS). Co-inoculation with B. amyloliquefaciens and AMF, resulted in the highest plant biomass and yield under WW and DS conditions.The nuclear DNA content analysis suggested that co-inoculation with B. amyloliquefaciens and AMF decreased the inhibition of drought stress on both the size and granularity of seed cells, which were comparable to the normal level. The single or co-inoculation with B. amyloliquefaciens and AMF increased the primary metabolites content and alleviated the drought-induced reduction in soluble sugars, lipids, protein and oil contents. Plant inoculation induced the expression of genes involved in lipid and protein biosynthesis, whereas an opposite trend was observed for genes involved in lipid and protein degradation, supporting the observed increase in lipid and protein content. Plant inoculated with B. amyloliquefaciens showed the highest α-amylase and β-amylase activities, indicating improved osmolyte (soluble sugar) synthesis, particularly under drought. Interestingly, single or co-inoculation further strengthen the positive effect of drought on the antioxidant and osmoprotectant levels, i.e. phenol, flavonoid, glycine betaine contents, and glutathione-S-transferase (GST) activity. As a result of stress release, there was a decrease in the level of stress

No abstract

No abstract

Guar is an economically important legume crop that is used for gum production. The clean and sustainable production of guar, especially in newly reclaimed lands, requires biofertilizers that can reduce the use of mineral fertilizers, which have harmful effects on human health and the environment. The present study was conducted to investigate the effects of biofertilizers produced from Bradyrhizobium sp., Bacillus subtilis, and arbuscular mycorrhizal fungi (AMF), individually or in combinations, on microbial activity, and nutrients of the soils and the guar growth and seed quality and yield. The application of biofertilizers improved shoot length, root length, number of branches, plant dry weight, leaf area index (LAI), chlorophyll content, and nutrient uptake of guar plants compared with the control plants. Moreover, the application with biofertilizers resulted in an obvious increase in seed yield and has improved the total proteins, carbohydrates, fats, starch, and guaran contents in the seeds. Additionally, biofertilizer treatments have improved the soil microbial activity by increasing dehydrogenase, phosphatase, protease, and invertase enzymes. Soil inoculation with the optimized doses of biofertilizers saved about 25% of the chemical fertilizers required for the entire guar growth stages. Our results could serve as a practical strategy for further research into integrated plant-microbe interaction in agriculture.

We examined three different-ploidy wheat species to elucidate the development of aboveground architecture and its domesticated mechanism under environment-controlled field conditions. Architecture parameters including leaf, stem, spike and canopy morphology were measured together with biomass allocation, leaf net photosynthetic rate and instantaneous water use efficiency (WUEi). Canopy biomass density was decreased from diploid to tetraploid wheat, but increased to maximum in hexaploid wheat. Population yield in hexaploid wheat was higher than in diploid wheat, but the population fitness and individual competition ability was higher in diploid wheats. Plant architecture was modified from a compact type in diploid wheats to an incompact type in tetraploid wheats, and then to a more compact type of hexaploid wheats. Biomass accumulation, population yield, harvest index and the seed to leaf ratio increased from diploid to tetraploid and hexaploid, associated with heavier specific internode weight and greater canopy biomass density in hexaploid and tetraploid than in diploid wheat. Leaf photosynthetic rate and WUEi were decreased from diploid to tetraploid and increased from tetraploid to hexaploid due to more compact leaf type in hexaploid and diploid than in tetraploid. Grain yield formation and WUEi were closely associated with spatial stance of leaves and stems. We conclude that the ideotype of dryland wheats could be based on spatial reconstruction of leaf type and further exertion of leaf photosynthetic rate.

No abstract