Number Of Grains Research Articles

Trade-offs between grain number, grain weight and fruiting efficiency of different bread wheat genotypes in response to anthesis drought stress

Cereal crops in Morocco are mainly cultivated under rainfed conditions of dryland regions. Under these conditions, they are mostly exposed to drought stress that affects different yield components. We studied the effect of anthesis drought stress on the relationships among the components of grain number (GN), thousand grains weight (TGW), fruiting efficiency (FE) and yield. And we examined fruiting efficiency (FE= grains set per g of spike dry weight at anthesis) as promising trait for further increasing yield without compromising yield components. Greenhouse experiments were conducted on 2019/2020, 2020/2021 and 2021/2022 cropping seasons. Two contrasting water regimes, irrigated and stressed treatments at anthesis growth stage were assessed. Results showed that anthesis drought stress affects negatively all components studied. Substantial decrease of 10%, 16%, 9% and 34% were recorded for GN, TGW, FE, and yield, respectively, under water stress compared to irrigated treatments. Two genotypes, namely 15/42 and Achtar, were found to be the most adapted to both stressed and irrigated conditions. Under stressed conditions yield becomes less correlated with GN (r = 0.36) and FE (r = 0.37) and more correlated with TGW (r = 0.56*). GN becomes less correlated with FE (r = 0.02) and TGW (r = -0.14). While, FE becomes more correlated with TGW (r = 0.73*). To the extent of this study, FE was found as promising selection criterion under stress conditions without compromising TGW component.

Application of Various Concentrations of Moringa Leaf Liquid Fertilizer (Moringa oleifera L.) to Stimulate Growth and Yield of Upland Rice Under Various Drought Stresses

Upland rice is susceptible to drought stress in crops, especially on marginal lands. The use of moringa leaf liquid fertilizer as a biostimulant that is very rich in important compounds is expected to increase growth andproduction as well as plant tolerance to drought stress. This study aims to determine the appropriate concentrationof moringa leaf extract liquid fertilizer to inhibit the growth and yield of upland rice plants grown under variouslevels of drought stress. This study was arranged in the form of a 2-factor factorial experiment with randomizedcomplate block design Split plot design form. The main plot is the application of moringa leaf extract liquidfertilizer consisting of four concentration levels 0%, 5%, 10%, 15% moringa leaf liquid fertilizer. Subplots (SP)was drought stress consisting of three levels of percentage of Field Capacity, namely 100%, 75%, and 50% FC.There were 12 treatment combinations of two units in one replication, each treatment combination was repeated3 times for a total of 72 experimental units. The experiment of moringa leaf liquid fertilizer concentration gave asignificant effect on the increase of plant height, number of tillers, productive tillers, flag leaf area, number ofgrain per plant, grain weight per plant, and grain production per hectare at several levels of droughtstress.Concentration of 15% Moringa leaf liquid fertilizer gives a better effect in increasing the productivity ofupland rice with an average yield of 1507.03 tons/hectare under moderate stress (75% field capasity), and anaverage yield of 1081.66 tons/hectare under high drought stress (50% field capasity).

Effect of spraying with different concentrations of the growth regulator paclobutrazol on the yield characteristics of three varieties of oat crop Avena sativa L.

The experiment was conducted at the Research Station of the College of Agriculture, University of Basrah,located north of Basrah city, during the winter season of 2022-2023, in a loamy soil. The study aimed toinvestigate the response of three varieties of oats (Avena sativa L.) to foliar spraying with differentconcentrations of the growth regulator paclobutrazol. The study included three oat varieties (Ganzania,Shafa, and CarlIoup) under the influence of spraying three concentrations of paclobutrazol (25, 50, and100 mg/L) and a control treatment. The interaction between the two factors was also studied. Thespraying was carried out in two stages, the first at the beginning of branching, and the second after threeweeks from the first spray.The experiment was arranged using a randomized complete block design(RCBD) with three replicates. The results showed the superiority of the paclobutrazol treatment (50 mg.l-1), which recorded the highest averages for most of the studied yield characteristics, as the lowestaverage number of panicles m-2was recorded at 458.05 dalia - and the highest average number of grainsper dalia was 55.45 grains g-1, and the highest average weight was recorded. 1000 grains amounted to37.33 g, while the Ganzania variety was superior in terms of the number of days and the number ofgrains in of panicl and 1000 grains amounted to 458.05 and amounted to 55.45 grains in of panicl-1 and 34.93 g and its components, protein content in grains, and chlorophyll in leaves were studied. Theresults showed the superiority of the paclobutrazol treatment (50 mg/L), which recorded the highestmeans for most of the studied growth traits. It had the lowest average plant height, reaching 70.75 cm. Italso recorded the highest average chlorophyll content, reaching 143.90 mg/100 g, and the highest averagefor the number of tillers, reaching 488.97 tillers/m². Additionally, it recorded the highest average for stemdiameter, reaching 4.49 mm.

Agronomic performance of plant growth-promoting microorganisms and nitrogen sufficiency index in common bean

This work aimed to assess Rhizobium tropici, Azospirillum brasilense, and Trichoderma asperellum co-inoculation effects, besides N-fertilizer supplementation as determined by the nitrogen sufficiency index (NSI) on the development of common bean. Field trials were carried out in a randomized block design with four replicates at three different locations. Treatments consisted of sole or combined inoculation of R. tropici, A. brasilense, and T. asperellum, besides N-fertilization. Seeds were inoculated with R. tropici and/or T. asperellum using 10 g of each inoculant kg−1 of seed. At the phenological stage V2/V3 A. brasilense was inoculated using 300 ml ha−1. Nitrogen sufficiency index (NSI), number of nodules (NN), nodule dry mass (NDM), root dry mass (RDM), shoot dry mass (SDM), number of pods (NP), number of grains (NG), and grain yield (GY) were assessed. NN and NDM were higher under R. tropici, A. brasilense, and T. asperellum co-inoculation. This same co-inoculation provided RDM and SDM similar to the use of 120 kg ha−1 of N. R. tropici, A. brasilense, and T. asperellum co-inoculation supplemented with N-fertilizer at the phenological stage R5, provide NP and NG similar to 120 kg ha−1 N, and to 80 kg ha−1 N supplemented with N at the phenological stage V4. NSI was effective to determine the N needs of common bean. The co-inoculation of two doses ha−1 of R. tropici, three doses ha−1 of A. brasilense and two doses ha−1 of T. asperellum, supplemented with N-fertilizer at phenological stage V4 based on NSI, stimulated growth and yield components of common bean, providing GY equivalent to the N-fertilized treatments.

Assessment of variation among cultivated wheat species for plant nutrient strata under salinity conditions

Six wheat genotypes, two each of bread wheat (UAS BW-13897 and LBPY 2014-5), Triticum durum (GW 2010-679 and UAS DW-31403) andT. dicoccum (DIC 99 and DIC 26) were grown under natural saline and control conditions to observe the existence of ion discrimination,ion selectivity amenable to ion regulation and ion interactions among them. Bread wheat genotype, UAS BW-13897 showed a highK+ and K+/Na+ ratio at the harvesting stage under saline condition indicating its high salt tolerance. Contrary to it, T. durum genotype,UAS DW-31403 was found to be highly salt-sensitive due to its low K+/Na+ ratio and high Na+ absorption. Bread wheat genotypes werefound most salt-tolerant due to better exclusion of Na+ salt, with negligible reduction in grain yield, spike length, SPAD and numberof grains per spike. The salt exclusion was found less apparent in T. durum and T. dicoccum wheat likely due to the absence of the Dgenome and Kna1 gene, which is present in bread wheat and not in the two tetraploid species. Durum wheat was observed to be mostsensitive with low salt exclusion capacity, whereas T. dicoccum wheat was found intermediate between bread and durum wheat withmedium salt exclusion capacity. The study revealed a difference in type and level of salt tolerance in different species and genotypesthat established high Na+ salt exclusion capacity as one of the important selection criteria for salt tolerance.

Impact of rising temperatures on historical wheat yield, phenology, and grain size in Catalonia.

Climate change poses significant challenges to agriculture, impacting crop yields and necessitating adaptive strategies in breeding programs. This study investigates the genetic yield progress of wheat varieties in Catalonia, Spain, from 2007 to 2021, and examines the relationship between genetic yield and climate-related factors, such as temperature. Understanding these dynamics is crucial for ensuring the resilience of wheat crops in the face of changing environmental conditions. Genetic yield progress was assessed using a linear regression function, comparing the average yield changes of newly released wheat varieties to benchmark varieties. Additionally, a quadratic function was employed to model genetic yield progress in winter wheat (WW). The study also analyzed correlations between genetic yield (GY) and normalized values of hectoliter weight (HLW) and the number of grains (NG) for both spring wheat (SW) and WW. Weather data were used to confirm climate change impacts on temperature and its effects on wheat growth and development. The study found that genetic yield was stagnant for SW but increased linearly by 1.31% per year for WW. However, the quadratic function indicated a possible plateau in WW genetic yield progress in recent years. Positive correlations were observed between GY and normalized values of HLW and NG for both SW and WW. Climate change was evident in Catalonia, with temperatures increasing at a rate of 0.050 °C per year. This rise in temperature had detrimental effects on days to heading (DH) and HLW, with reductions observed in both SW and WW for each °C increase in annual minimum and average temperature. The findings highlighted the urgent need to address the impact of climate change on wheat cultivation. The stagnation of genetic yield in SW and the potential plateau in WW genetic yield progress call for adaptive measures. Breeding programs should prioritize phenological adjustments, particularly sowing date optimization, to align with the most favorable months of the year. Moreover, efforts should be made to enhance HLW and the number of grains per unit area in new wheat varieties to counteract the negative effects of rising temperatures. This research underscores the importance of ongoing monitoring and adaptation in agricultural practices to ensure yield resilience in the context of a changing climate.

Roots and shoot traits contributing to drought tolerance from germination to maturity stages for bread wheat

Drought is the major bottleneck for food security worldwide. Identifying reliable selection traits that sustain plant growth and productivity under water-deficient conditions is essential for releasing resilient drought tolerant wheat genotypes. Herein, in order to identify the best combination of drought tolerance related-traits, this study was carried out to assess the effect of 21 shoot and 17 root secondary traits on grain yield of 40 bread wheat genotypes from germination to maturity stages under laboratory, greenhouse and field conditions. In this research, germination rate (GR), mean germination time (MGT), roots weight (RW), roots number (RN) and Root : Shoot ratio (R/S) were relevant for discriminating drought tolerant genotypes, expressing negative moderate correlation (r~-0.5) and explaining a significant part of yield variation (8 to 30%). Grain number (GN) was the most important agronomic trait (r~0.70-0.94) which explained up to 88 % of yield variation. This latter effect is reinforced by the indirect effects of productive spikes number (FSN), thousand kernel weight (TKW) and grains number per fertile spike (GNFS). The biomass (BY), ground cover (GC), spike (SL) and pedoncule lengths (PL) were also relevant, especially under severe stress (r=0.4-0.6 ; β=0.33-0.40) ; while the canopy temperature depression (CTD) was determinant under moderate stress (r=-0.45 ; β=-0.46). Combined selection for these traits will be effective to improve the process of developing high-yielding bread wheat varieties adapted to drought prone areas.

Nitrogen efficiency indexes association with nitrogen recovery, utilization, and use efficiency in spring barley at various nitrogen application rates

AbstractThe nitrogen use efficiency (NUE) is the ratio of the N uptake by the plant to the total amount of applied N fertilizer. The optimization of NUE is essential for sustainable agriculture, especially in the breeding programs to improve the yield of barley (Hordeum vulgare L.). We investigated the NUE variation in 32 barley genotypes and to examine the response relationship between phenotypic traits and N level to determine the traits essential for the selection of breeding programs to optimize the NUE. The NUE was investigated in 32 barley genotypes for 2 yr under field conditions using three N levels (60, 120, and 180 kg N ha−1). Growth, physiological and agronomic traits, and N efficiency‐related parameters were determined. The parameters investigated were significantly affected by N application and its interactions with traits. Plant height, biological yield, spike length, and grain number (GN) were increased at higher N levels, but the 1,000‐grain weight decreased. The lowest grain yield was 2,000.7 kg ha−1 at 60 kg N ha−1, and the highest was 8,607.9 kg ha−1 at 120 kg N ha−1. An increase in the N rate from 60 to 120 kg N ha−1 was associated with a higher total chlorophyll content (CHLSPAD) (from 19.04 to 23.13), but no significant change in CHL was seen at 180 kg N ha−1. The agronomic nitrogen use efficiency (ANUE), fertilizer N recovery efficiency and the nitrogen utilization efficiency were both reduced with an increase of the N application rate. A path analysis revealed that GN was the most essential trait for NUE breeding program selection due to its high direct effect (0.72) on ANUE. A linear discriminant analysis showed that CHL at 60 d after sowing was the best trait for distinguishing low from high N levels.

Soybean development under different Aphelenchoides besseyi and Meloidogyne incognita populations

The green stem Aphelenchoides besseyi and gall Meloidogyne incognita phytonematodes cause soybean yield losses. Thus, the objective of this study was to evaluate the effects of different populations of A. besseyi and M. incognita on soybeans. The experiment had 10 treatment groups [T1: control, T2: A. besseyi (500), T3: M. incognita (2,000), T4: A. besseyi (250) + M. incognita (2,000), T5: A. besseyi (500) + M. incognita (2,000), T6: A. besseyi (250) + M. incognita (4000), T7: A. besseyi (500) + M. incognita (4,000) individuals, T8: A. besseyi (250) + M. incognita (8,000), T9: A. besseyi (500) + M. incognita (5,000), and T10: A. besseyi (1,000) + M. incognita (8,000) individuals] with six replicates. Inoculations were done on day 10 after soybean germination, and evaluations were conducted after 60 d. Plant height, shoot fresh weight, root fresh weight, number of pods (NP), pod fresh weight, number of grains (NG), grain yield (GY), amount of A. besseyi in the shoot, and M. incognita in the roots were analyzed. The 500 A. besseyi + 8,000 M. incognita treatment reduced all variables and led to considerable damage to soybean development. In addition, GY, NG, and NP were reduced in the different nematode population density groups, influencing soybean agronomic characteristics.

Manifestation of Heterosis and Degree of Phenotypic Dominance by the Number of Grains from the Main Ear in the Hybridisation of Different Early-Maturing Varieties of Soft Winter Wheat

Winter wheat (Triticum aestivum L.) is the main food crop on a global scale, in the growth and stabilisation of yields, of which varietal resources are a significant factor. In practical breeding work, an essential role is played by a variety of thoroughly investigated source material. The purpose of this study was to determine hypothetical and true heterosis and establish the nature of inheritance of the number of grains from the main ear in hybrids of soft winter wheat. In 2018-2020, 45 combinations of cross-breeding of soft winter wheat varieties obtained from hybridisation of different growing season periods were investigated in the experimental field of the Research and Production Centre of the Belotserkovskyi National Agrarian University. Generally accepted methods were used to determine the hypothetical and true heterosis and the degree of phenotypic dominance by the number of grains in the main ear. Studies indicate that the number of grains in the ear of the main stem of the parent components of hybridisation is determined by genotype and considerably depends on the hydrothermal conditions of the year. The author of this paper established the influence of maternal cytoplasm on the manifestation of the trait under study. Thus, when used in hybridisation of early-maturing varieties with the mother form, the largest average number of grains in the main ear for hybrids (63.3 pcs.) was formed in 2019. At the same time, for the use of medium-early, medium maturing, and medium-late varieties in hybridisation, the maximum number of grains (64.8 pcs.) was marked in 2018. Therewith, all hybrids formed the minimum number of grains in 2020. The obtained experimental data indicate the influence of parental genotypes and year conditions on heterosis indicators and the degree of phenotypic dominance in first-generation hybrids. It is determined that the most common type of inheritance (85.6%) of the number of grains from the main ear is positive overdomination. Practical value for the selection of soft winter wheat are the selected cross-breeding combinations: Myronivska early / Zolotokolosa, Myronivska early / Cherniava, Bilotserkivska semi-dwarf / Cherniava, Bilotserkivska semi-dwarf / Antonivka, Kolchuha / Antonivka, Zolotokolosa / Charniava, Zolotokolosa / Yednist, Cherniava / Vidrada, Cherniava / Stolychna, Shchedra Nyva / Dobirna, Antonivka / Stolychna, Dobirna / Pyvna, which significantly exceeded the average number of grains from the main ear for F1 in the changing fields under hydrothermal conditions the years of research

Meta-QTLs, ortho-meta-QTLs and candidate genes for grain yield and associated traits in wheat (Triticum aestivum L.).

In wheat, 2852 major QTLs of 8998 QTLs available for yield and related traits were used for meta-analysis; 141 meta-QTLs were identified, which included 13 breeder's MQTLs and 24 ortho-MQTLs; 1202 candidate genes and 50 homologues of genes for yield from other cereals were also identified. Meta-QTL analysis was conducted using 2852 of the 8998 known QTLs, retrieved from 230 reports published during 1999-2020 (including 19 studies on tetraploid wheat) for grain yield (GY) and the following ten component traits: (i) grain weight (GWei), (ii) grain morphology-related traits (GMRTs), (iii) grain number (GN), (iv) spikes-related traits (SRTs), (v) plant height (PH), (vi) tiller number (TN), (vii) harvest index (HI), (viii) biomass yield (BY), (ix) days to heading/flowering and maturity (DTH/F/M), and (x) grain filling duration (GFD). The study resulted in the identification of 141 meta-QTLs (MQTLs), with an average confidence interval (CI) of 1.4cM as against a CI of > 12.1cM (8.8 fold reduction) in the QTLs that were used. The corresponding physical length of CI ranged from 0.01Mb to 661.9Mb (mean, 31.5Mb). Seventy-seven (77) of these 141 MQTLs overlapped marker-trait associations (MTAs) reported in genome-wide association studies. Also, 63 MQTLs (each based on at least 10 QTLs) were considered stable and robust, with 13 MQTLs described as breeder's MQTLs (selected based on small CI, large LOD, and high level of phenotypic variation explained). Thirty-five yield-related genes from rice, barley, and maize were also utilized to identify 50 wheat homologues in MQTLs. Further, the use of synteny and collinearity allowed the identification of 24 ortho-MQTLs which were common among the wheat, barley, rice, and maize. The results of the present study should prove useful for wheat breeding and future basic research in cereals including wheat, barley, rice, and maize.

COMMON BEAN YIELD AS AFFECTED BY IN FURROW FILLER LIMING AND NITROGEN TOPDRESSING1

ABSTRACT The use of filler liming in the sowing furrow can improve the chemical characteristics of the soil and, together with nitrogen fertilization, increase common bean yield. The objective of this study was to determine the effect of filler liming of the sowing furrow along with nitrogen topdressing fertilization on the yield of common bean, cultivar Pérola, irrigated by central pivot, in the Cerrado Region. The field experiments were conducted for three consecutive cropping years, in a randomized block design with four replications, in a 2x4 factorial scheme, consisting of two doses of nitrogen topdressing fertilization (zero and 60 kg ha-1 of N) and four doses of filler liming application in the sowing furrow (0, 200, 400 and 600 kg ha-1 of CaCO3). The plant density (PD), number of pods (NP), number of grains (NG), mass of 100 grains (M100) and, grain yield (GY) were evaluated. The use of 60 kg ha-1 of N provided greater M100 and GY. The increase of the filler liming doses in the sowing furrow led to a reduction of the NP. The filler liming dose of 200 kg ha-1 provided higher values of NG and M100, and when combined with the nitrogen topdressing fertilization, improved the GY of the common bean.

Exploring the nitrogen source-sink ratio to quantify ear nitrogen accumulation in maize and wheat using critical nitrogen dilution curve

Ear nitrogen (N) accumulation plays an imperative role in ear photosynthesis and the formation of grain yield and quality of maize and wheat. However, the mechanism governing ear N accumulation (NAe) especially under different N levels is not yet clear. For this purpose, this study endeavored to describe the N source-sink ratio of NAe by developing a model using ear critical N concentration (%Nc) dilution curves of maize and wheat. The data obtained include ear dry matter (DMe), NAe, ear N nutrition index (NNIe), ear N accumulation rate index (NARIe), post-anthesis N uptake (PANU), grain number (GN), and thousand-grain weight (TGW) were collected from 12 varied N rates (0–300 kg N ha−1) field experiments conducted using four wheat and three maize cultivars. Integrated models were developed to show the effect of N source and sink on NAe in maize and wheat. The ratio between PANU and NAe was used to represent the post-anthesis supply capacity of N source, while DMe was used as the storage capacity of N sink in these models. Robust relationships of NARIe with the ratio between PANU and NAe in maize and wheat indicated that NAe was controlled by N source from N-limiting to non-N-limiting levels. The relationship between the rate of ear dry matter accumulation (DMRe) and NNIe showed a linear plateau model across different N levels due to the similar DMe under non-N-limiting levels, indicating that ear N status was regulated by DMe (N sink) under N-limiting levels. Therefore, NAe under N-limiting levels was co-regulated by N source and sink. Besides, the temporal effect of plant N status before anthesis on NAe was also observed. The close relationship between DMe and plant N status at anthesis across different N levels in maize and wheat indicated that the potential ear N sink was controlled by the pre-anthesis supply capacity of plant N source. Consequently, pre-anthesis plant N status was imperative for quantifying potential ear N sink. This was the first-ever attempt to investigate the N source-sink ratio of NAe using ear %Nc curve and highlighted the effect of pre-anthesis plant N status on NAe. The findings will contribute towards a better understanding of the process of NAe under different N levels for developing a judicious N management strategy for improving the N use efficiency of wheat and maize.

Assessment of Consortia Inoculation Effects on the Agronomical Performance of the Common Bean

ABSTRACT The massive use of inputs is often applied in common bean for nitrogen (N) supply, better plant development, and to prevent plant disease. Instead, the co-inoculation of Rhizobium, Azospirillum and Trichoderma may play the same role; however, its effects are unknown in common bean. This work aimed to evaluate the effects of co-inoculating three microorganisms on the development, nodulation and grain yield (GY) of a common bean. The experiments were carried out on a randomized block design with four replicates. The treatments were NI: not inoculated; Rt: inoculated with Rhizobium tropici; Rt+Ab: inoculated with Rt and Azospirillum brasilense; Rt+Ab+Ta: inoculated with Rt, Ab and Trichoderma asperellum; Nf120: 120 kg ha−1 of N. In the inoculated treatments, the seeds were treated with Rt inoculant and with Ta inoculant before sowing, using a dose of 10 g of each inoculant kg−1 of seed. The inoculant containing the Ab was sprayed out in a dose of 300 mL ha−1 at the V2/V3 phenological stage. Evaluations were performed for the number of nodules (NN), nodule dry weight (NDW), root dry weight (RDW), shoot dry weight (SDW), pod number (PN), grain number (GN) and GY. NN and NDW were higher in NI and Rt treatments. The Rt+Ab treatment resulted in higher SDW, whereas the same treatment and Rt+Ab+Ta provided higher RDW and SDW, resulting in values similar to those of the Nf120 treatment. Innoculation with rhizobia (Rt) provided PN and GN equivalent to those of the Nf120 treatment. The inoculation (Rt) and co-iconulation (Rt+Ab) resulted on GY of 2946.27 and 2892.42 kg ha−1, respectively, surpassing the Nf120 treatment, which was 2741.91 kg ha−1. These results indicate that Rt inoculation and Rt+Ab co-inoculation can be alternatives to the substitution of nitrogen fertilizers, guaranteeing high GY levels in common bean.

Selection approaches to the variation of responses to soil compaction stress among maize hybrids (Zeamays L.)

AbstractSoil compaction stress can strongly affect plant growth, development and productivity. Effects of different levels of soil compaction were investigated in 18 maize hybrids during field and greenhouse experiments. Maize hybrids in the field experiments were subjected to low (L) or high (H) and in the greenhouse experiments to low (L: 1.10) and high (C: 1.60 g cm−3 soil) soil compaction level. Differences between maize hybrids grown under non‐stress and stress conditions were found in a decrease in grain yield (GY), grain number (GN), weight of 1,000 grain (W‐1000), seedling dry matter (DM), emergence (EM), plant height (H), leaf area (LA) and leaf greening (SPAD). Stress susceptibility index (SSI), geometric mean productivity index (GMP) and tolerance index (TI) were evaluated by determining the effects of low (L) or high (H) soil compaction levels on grain yield (GY) or dry matter of the above‐ground part (DM). The values of SSI, GMP and TI enabled us to rank the tested hybrids with respect to their susceptibility to soil compaction stress. SSI and TI made it possible to identify maize hybrids resistant and sensitive to soil compaction stress. Changes in growth traits were greater in the hybrids with high SSI and TI. Correlation coefficient (r) between stress susceptibility index (SSI) of maize hybrids in the field and greenhouse experiment was high and statistically significant. This observation may indicate that genetically determined susceptibility to soil compaction stress in maize hybrids was similar throughout ontogenesis.

Resolving a QTL complex for height, heading, and grain yield on chromosome 3A in bread wheat

Crop height (Ht), heading date (Hd), and grain yield (GY) are inter-related in wheat. Independent manipulation of each is important for adaptation and performance. Validated quantitative trait loci (QTLs) for all three co-locate on chromosome 3A in the Avalon×Cadenza population, with increased Ht, Hd, and GY contributed by Cadenza. We asked if these are linked or pleiotropic effects using recombinant lines, and showed that Ht and Hd effects are independent. The Chinese Spring equivalent to the newly defined Ht interval contained a gene cluster involved in cell wall growth and displaying high levels of differential transcript expression. The Hd locus is larger and rearranged compared with the reference genome, but FT2 (Flowering Locus T2) is of particular interest. The Hd effect acted independently of photoperiod and vernalization, but did exhibit seasonal genotype×environment interaction. Recombinants were phenotyped for GY in replicated field experiments. GY was most associated with Cadenza alleles for later Hd, supporting physiological studies using the same lines proposing that ‘late’ alleles at this locus increase spike fertility and grain number (GN). The work has uncoupled height from heading and yield, and shown that one of very few validated GY QTLs in wheat is probably mediated by phenological variation.

Response of the common bean to liquid fertilizer and Rhizobium tropici inoculation

The common bean production system is majorly based on the use of granular fertilizers to provide nutrients for the crop. Studies on the use of liquid fertilization at an appropriated depth and, seed inoculation with Rhizobium tropici can provide significant increases in the grain yield of the common bean. The objective of this study was to determine the growth and productivity of common bean as affected by N-P formulations, application depths and the inoculation with R. tropici. Field experiments were carried out in 2015 and 2016 cropping years using a complete block design, in a 2x2x2 factorial arrangement, with four replicates. The treatments involved the combination of N-P formulation (granular and liquid), two application depths of the N-P formulation (6 and 12 cm) and with or without rhizobia inoculant. The plant density (PD), number of pods (NP), number of grains (NG), mass of 100 grains (M100) and grain yield (GY) were determined. The granular and liquid N-P formulations provided similar results for PD, NP, NG, and GY of common bean. Similarly, the application depth of the N-P formulations did not affect GY. Inoculation of the seed with R. tropici stimulated NP and NG, increasing GY. Growth and productivity parameters were equally affected by the type of formulation and application depth; however, GY was greater with rhizobial inoculant. Thus, the liquid N-P formulation, applied at 6 cm depth, associated with rhizobial inoculant can improve the crop management providing better control of application uniformity, minimal soil mobilization, less fuel consumption, and increased grain yield.

Soybean Yield Estimation and Its Components: A Linear Regression Approach

Soybean yield estimation is either based on yield monitors or agro-meteorological and satellite imagery data, but they present several limiting factors regarding on-farm decision level. Aware that machine learning approaches have been largely applied to estimate soybean yield and the availability of data regarding soybean yield and its components (number of grains (NG) and thousand grains weight (TGW)), there is an opportunity to study their relationships. The objective was to explore the relationships between soybean yield and its components, generate equations to estimate yield and evaluate its prediction accuracy. The training dataset was composed of soybean yield and its components’ data from 2010 to 2019. Linear regression models based on NG, TGW and yield were fitted on the training dataset and applied to a validation dataset composed of 58 on-field collected samples. It was found that globally TGW and NG presented weak (r = 0.50) and strong (r = 0.92) linear relationships with yield, respectively. In addition to that, applying the fitted models to the validation dataset, model based on NG presented the highest accuracy, coefficient of determination (R2) of 0.70, mean absolute error (MAE) of 639.99 kg ha−1 and root mean squared error (RMSE) of 726.67 kg ha−1.

Chickpea production in response to fertilization with zinc and doses of phosphorus

Chickpea cultivation in Brazil has not yet been consolidated, and studies aiming at the adequate nutritional management for this crop are necessary. This work aimed to evaluate the production of chickpea plants (cultivar BRS Aleppo) subjected to fertilization with zinc and P doses. The experimental was completely randomized, with four replications, in a 3 x 5 factorial scheme, corresponding to three fertilization treatments with Zn (without Zn addition; 50% of Zn applied at sowing, via soil + 50% applied at flowering, via leaves; and 100% applied at sowing, via soil) and five doses of phosphorus (0, 60, 120, 180, and 240 kg ha-1 of P2O5). The 100-grain mass (M100), pod mass (MV), number of pods (NV), number of grains (NG), total grain mass (MGT), yield (PROD), dry matter of the shoot part (MSPA) and plant residues (MSRV), and agronomic efficiency (EA) were characterized. There was an isolated effect of the P doses on the M100, MGT, PROD, MSPA, and MSRV characteristics. The application of 240 kg ha-1 resulted in an increase in the production components and a maximum yield of 3,018 kg ha-1, indicating the need to adopt higher doses of P2O5 to increase chickpea production in tropical soils. However, the highest agronomic efficiency was obtained after the application of 60 kg ha-1 of P2O5, along with Zn at sowing.

A comprehensive study of spike fruiting efficiency in wheat

AbstractSpike fruiting efficiency (FE), defined as grains per unit of spike dry weight at anthesis (SDWa) is a promising trait for improving grain number (GN) in wheat (Triticum aestivum L.). It is often estimated at maturity as the grains per unit of chaff or FE at maturity (FEm). The fertile floret efficiency (FFE), defined as fertile florets per unit of SDWa, and grain set (GST), or the number of grains per floret, were studied to better understand FE determination for the first time. Two double haploid populations designed by crossing modern cultivars contrasting for FE [‘Baguette 19’ and ‘Baguette Premium 11’(high FE) × ‘BioINTA2002’ (low FE)] were sown in five environments. The FE and FEm showed an unstable correlation (low or high) among genotypes within environments (caused by variable SDWa–chaff associations), resulting in a worse correlation between GN and FEm than between GN and FE. Therefore, the use of FEm as a surrogate for FE to improve GN may yield lower gains than those expected if FE were used. The narrow‐sense heritability of FFE was high but the variability in fertile florets per spike among genotypes within environments was correlated with FFE only in the environments with high SDWa. Despite the close association between FE and FFE, the former was not totally set at anthesis, as GST greatly affected FE and GN. Selecting for higher FFE and GST, where genotype × environment effects determine heavy spikes at anthesis, is an alternative to breeding for improved GN.