Contribution of biological nitrogen fixation to cowpea: a strategy for improving grain yield in the semi-arid region of Brazil

2003 ◽  
Vol 38 (6) ◽  
pp. 333-339 ◽  
Author(s):  
L. M. V. Martins ◽  
G. R. Xavier ◽  
F. W. Rangel ◽  
J. R. A. Ribeiro ◽  
M. C. P. Neves ◽  
...  
2012 ◽  
Vol 45 ◽  
pp. 109-114 ◽  
Author(s):  
Ana Dolores Santiago de Freitas ◽  
Acácia Fernandes Silva ◽  
Everardo Valadares de Sá Barretto Sampaio

Atmosphere ◽  
2021 ◽  
Vol 12 (7) ◽  
pp. 927
Author(s):  
Jamshad Hussain ◽  
Tasneem Khaliq ◽  
Muhammad Habib ur Rahman ◽  
Asmat Ullah ◽  
Ishfaq Ahmed ◽  
...  

Rising temperature from climate change is the most threatening factor worldwide for crop production. Sustainable wheat production is a challenge due to climate change and variability, which is ultimately a serious threat to food security in Pakistan. A series of field experiments were conducted during seasons 2013–2014 and 2014–2015 in the semi-arid (Faisalabad) and arid (Layyah) regions of Punjab-Pakistan. Three spring wheat genotypes were evaluated under eleven sowing dates from 16 October to 16 March, with an interval of 14–16 days in the two regions. Data for the model calibration and evaluation were collected from field experiments following the standard procedures and protocols. The grain yield under future climate scenarios was simulated by using a well-calibrated CERES-wheat model included in DSSAT v4.7. Future (2051–2100) and baseline (1980–2015) climatic data were simulated using 29 global circulation models (GCMs) under representative concentration pathway (RCP) 8.5. These GCMs were distributed among five quadrants of climatic conditions (Hot/Wet, Hot/Dry, Cool/Dry, Cool/Wet, and Middle) by a stretched distribution approach based on temperature and rainfall change. A maximum of ten GCMs predicted the chances of Middle climatic conditions during the second half of the century (2051–2100). The average temperature during the wheat season in a semi-arid region and arid region would increase by 3.52 °C and 3.84 °C, respectively, under Middle climatic conditions using the RCP 8.5 scenario during the second half-century. The simulated grain yield was reduced by 23.5% in the semi-arid region and 35.45% in the arid region under Middle climatic conditions (scenario). Mean seasonal temperature (MST) of sowing dates ranged from 16 to 27.3 °C, while the mean temperature from the heading to maturity (MTHM) stage was varying between 12.9 to 30.4 °C. Coefficients of determination (R2) between wheat morphology parameters and temperature were highly significant, with a range of 0.84–0.96. Impacts of temperature on wheat sown on 15 March were found to be as severe as to exterminate the crop before heading. The spikes and spikelets were not formed under a mean seasonal temperature higher than 25.5 °C. In a nutshell, elevated temperature (3–4 °C) till the end-century can reduce grain yield by about 30% in semi-arid and arid regions of Pakistan. These findings are crucial for growers and especially for policymakers to decide on sustainable wheat production for food security in the region.


2021 ◽  
Vol 11 ◽  
Author(s):  
Vinício Oliosi Favero ◽  
Rita Hilário Carvalho ◽  
Victória Monteiro Motta ◽  
Ana Beatriz Carneiro Leite ◽  
Marcia Reed Rodrigues Coelho ◽  
...  

The mung bean has a great potential under tropical conditions given its high content of grain protein. Additionally, its ability to benefit from biological nitrogen fixation (BNF) through association with native rhizobia inhabiting nodule microbiome provides most of the nitrogen independence on fertilizers. Soil microbial communities which are influenced by biogeographical factors and soil properties, represent a source of rhizobacteria capable of stimulating plant growth. The objective of this study is to support selection of beneficial bacteria that form positive interactions with mung bean plants cultivated in tropical soils, as part of a seed inoculation program for increasing grain yield based on the BNF and other mechanisms. Two mung bean genotypes (Camaleão and Esmeralda) were cultivated in 10 soil samples. Nodule microbiome was characterized by next-generation sequencing using Illumina MiSeq 16S rRNA. More than 99% of nodule sequences showed similarity with Bradyrhizobium genus, the only rhizobial present in nodules in our study. Higher bacterial diversity of soil samples collected in agribusiness areas (MW_MT-I, II or III) was associated with Esmeralda genotype, while an organic agroecosystem soil sample (SE_RJ-V) showed the highest bacterial diversity independent of genotype. Furthermore, OTUs close to Bradyrhizobium elkanii have dominated in all soil samples, except in the sample from the organic agroecosystem, where just B. japonicum was present. Bacterial community of mung bean nodules is mainly influenced by soil pH, K, Ca, and P. Besides a difference on nodule colonization by OTU sequences close to the Pseudomonas genus regarding the two genotypes was detected too. Although representing a small rate, around 0.1% of the total, Pseudomonas OTUs were only retrieved from nodules of Esmeralda genotype, suggesting a different trait regarding specificity between macro- and micro-symbionts. The microbiome analysis will guide the next steps in the development of an inoculant for mung bean aiming to promote plant growth and grain yield, composed either by an efficient Bradyrhizobium strain on its own or co-inoculated with a Pseudomonas strain. Considering the results achieved, the assessment of microbial ecology parameters is a potent coadjuvant capable to accelerate the inoculant development process and to improve the benefits to the crop by soil microorganisms.


Genetika ◽  
2016 ◽  
Vol 48 (1) ◽  
pp. 73-85 ◽  
Author(s):  
Jafar Ahmadi ◽  
Behroz Vaezi ◽  
Alireza Pour-Aboughadareh

The main goal of this study was to improve pure lines for low input agricultural areas of the semi-arid region of Iran and similar environmental conditions. Forty barley pure lines provided from ICARDA along with three check cultivars were evaluated under rain-fed conditions in a semi-arid region of Iran during two years (2011-2013). The experiments were conducted in a randomized complete block design with four replications to estimate genetic variation and heritability for agro-morphological traits. The highest values of phenotypic and genotypic coefficients of variation were observed for the number of grains per spike followed by peduncle length, early vigor and grain yield. The broad heritability estimates ranged from 24% for grain yield to 96% for the number of grains per spike. The highest and lowest expected genetic advance, observed for days to physiological maturity and the number of grains per spike, respectively. Results of stepwise regression and path analysis showed that hectoliter grain weight and thousand grain weight exhibited the highest direct effects on grain yield, respectively. Comparisons between the pure lines and check cultivars indicated that out of 40 pure lines, 27 lines had a higher grain yield. Also, the pure lines No. 29, 13, 9 and 33 were identified as the superior lines for semi-arid environmental conditions. Our results indicate that check cultivars could be improved by selecting for pure lines with taller peduncle and the number of grains per spike, but with heavier grains. Therefore, these lines can be used as genetic material to broaden the genetic basis of barley breeding programs all over the world.


Author(s):  
Rômulo M. O. de Freitas ◽  
Jeferson L. D. Dombroski ◽  
Francisco C. L. de Freitas ◽  
Narjara W. Nogueira ◽  
Tiago S. Leite ◽  
...  

ABSTRACT The resilience of crops to drought depends heavily on the cultural practices adopted, which can have a direct effect on water use efficiency. The aim of this study was to assess the influence of irrigation intervals on the growth, water consumption and water use efficiency of cowpea crops (cv. BRS Guariba) under conventional and no-tillage systems. The experiment was carried out in the semi-arid region of Rio Grande do Norte, Brazil, using a split-plot in a randomised complete block design, with four replications. Treatments consisted of two cultivation systems in the whole plots (conventional and no-tillage) and six irrigation intervals in the subplots (2, 6, 10, 14, 18 and 22 days) which were applied at full bloom. The biomass of the different parts of the plant, leaf area and leaf area index were assessed at 64 days after sowing (DAS) and grain yield, water consumption and water use efficiency at 70 DAS. No-tillage is a promising cultivation technique for cowpea crops, promoting higher grain yield and water use efficiency under semi-arid conditions. This system allows cowpea cultivation with irrigation intervals of 10 or 14 days, with no or small reduction in yield, respectively.


2021 ◽  
Vol 34 (2) ◽  
pp. 359-369
Author(s):  
AMANDA CORDEIRO DE MELO SOUZA ◽  
THIAGO PONTES LIRA ◽  
ANTONIO FÉLIX DA COSTA ◽  
FELIPE JOSÉ CURY FRACETTO ◽  
GISELLE GOMES MONTEIRO FRACETTO ◽  
...  

ABSTRACT Cowpeas (Vigna unguiculata L. Walp) are an economically and socially important legume in northern and north-eastern Brazil and can establish effective symbiosis with nitrogen-fixing bacteria. We evaluated the symbiotic compatibility and efficiency of rhizobial strains from Pernambuco semi-arid soils and determined their symbiotic stability on the IPA-206, BR 17-Gurguéia, and BRS Novaera cultivars, selected for different environments. The experiment was conducted in a greenhouse to evaluate a 3 × 28 factorial arrangement (cultivars selected for different environments × inoculation with the currently recommended strain, uninoculated plants with or without mineral nitrogen, and 25 rhizobial strains from semi-arid soils) in a randomized block design with four replicates. We determined nodule number, shoot and root dry matter, nodule dry matter by nodule number, nitrogen accumulated in the shoot by nodule dry matter, nitrogen content and accumulation in the shoot, relative efficiency of the recommended strain based on nitrogen accumulation, and shoot dry matter. Overall, the cultivars responded differently to different strains and cultivar biological nitrogen fixation potential. Strains G7.85 and BR 3262 showed potential for biological nitrogen fixation. BR 3262 was confirmed to be adequate for inoculation of different cowpea cultivars.


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