Lodging Index Research Articles

Zeolite alleviates potassium deficiency and improves lodging-related stem morphological characteristics and grain yield in rice

Zeolite is an abundant potassium (K)-rich silicate mineral that could increase K supply to plants. Potassium deficiency causes lodging problems and yield reductions in paddy fields in China. However, it is unknown whether zeolite amendments alleviate K deficiency or enhance lodging-related stem morphology characteristics in rice. A 2-year field experiment was conducted to evaluate the effect of zeolite amendment (0, 5 and 10 t ha–1) and K application (0, 30 and 60 kg ha–1) on rice grain yield, stem morphology, and K nutrient status in soil and plant tissues. In both years zeolite and K application, alone or in combination, significantly increased grain yield, mainly through increased number of panicles per plant with zeolite application and number of spikelets per panicle with K application. In the top 30 cm soil layer, zeolite amendment increased cation exchange capacity by up to 31% and available K by up to 38%. Zeolite or K application alone significantly increased stem, leaf and panicle K concentrations. Zeolite promoted K allocation to rice stems, and improved stem morphology associated with lodging index. In both years, zeolite or K application alone increased stem diameter, dry weight linear density and the breaking resistance moment by up to 7.0%, 8.3% and 16%, respectively, and decreased the stem lodging index by up to 6.7%. In summary, zeolite is an alternative source of K fertiliser and can alleviate K deficiency in paddy fields in China and elsewhere.

Genetic Variation, Heritability and Genetic Advance Among Semi-Dwarf Tef [<i>Eragrostis tef</i> (Zucc.) Trotter] Recombinant Inbred Lines with Emphasis to Lodging

Tef is the foremost cereal crop largely produced and consumed mostly in Ethiopia. It is grown on more than 3.1 million hectares annually. However, it’s productivity relatively low (1.85 t/ha). On the other hand, it gained recently global popularity “Super grain” as healthy and performance food due to its gluten free especially for celiac disease, diabetic and gluten allergy people. It has also high mineral contents like iron for anemia, bone and heart health as well as brain function. Lodging is a major constraint which affect both yields and quality of the grain as well as the straw. This experiment was led to assess genetic variability between the lines relating to lodging and other yield related traits. A total of forty-nine recombinant inbred lines were tested for 16 traits using simple lattice design on two sites. All the traits measured over the sites displayed highly significant differences among the lines except fertile tiller per plant, while their environmental interaction effect also highly significant for most of the traits measured. Grain yield showed the highest phenotypic coefficients of variation (PCV) (26.36%) followed by above ground biomass (23.16%), while the remaining traits showed low ( 60%), whereas half of the remained traits showed low ( 17.02%) and least for number of branches per panicle (0.09%). From all the traits evaluated in this study, plant height, panicle length showed high H2 and aboveground biomass performs relatively high values of GCV, PCV and GAM. Therefore, these traits are important for selection and further improvements. This study revealed that four recombinant inbred lines had higher yield and low lodging index than local as well as standard checks.

Cluster and Principal Component Analysis of Semi-Dwarf Tef [<i>Eragrostis tef</i> (Zucc.) Trotter] Recombinant Inbred Lines with Emphasis to Lodging

Tef is the main cereal crop widely produced and consumed in Ethiopia and preferred by millions of local smallholder farmers. It also gained recognition as a food crop in other parts of the world very recently due to its gluten-free grains and its nutritive value. Lodging is the major factor which greatly reduces both yields and quality of tef grain as well as the straw. The current study was conducted to group the lines as their similarities and assess the magnitude of genetic distances among them; then identify the contribution of individual traits for total variations. A total of 49 lines were evaluated for 16 traits using simple lattice design at Holetta and Debre Zeit in 2017 main rainy season. All the traits evaluated over the locations showed highly significant differences among the lines except fertile tiller per plant, while the lines x location interaction effect was highly significant for most of the traits evaluated. Cluster analysis grouped the lines into four clusters based on their similarity. The highest inter-cluster distance noted between clusters two and four while the lowest was between clusters one and four. Principal component analysis showed that about 77.6% of the gross variance among lines explained by five Principal components with eigenvalues greater than unity. This study revealed that four recombinant inbred lines had higher yield than local and standard checks. RIL# 14 showed highest grain yield, low lodging index and other desirable traits than all lines, which could base and strengthen future tef breeding if incorporated as plant material; especially for lodging problem.

Effects of Plant Growth Regulators and N Rate on the Morphological Traits of Generative Tillers and Seed Yields of Chewings and Strong Creeping Red Fescue

Plant growth regulators (PGRs) are used as a management tool to minimize plant height and subsequent stem lodging in grass seed crops. Their efficacy is influenced not only by the method of application, but also by the management and genetic variations within and between species. This aim of the study was to evaluate the effect of PGRs on morphological traits of generative tillers and seed yield of Festuca rubra L ssp. rubra (strong creeping red fescue) and F. r. L ssp. commutata (Chewings red fescue) under low and medium doses of spring nitrogen fertilization (40 and 70 kg N ha−1). PGRs were applied as: chlormequat chloride (CCC) at BBCH 30–31; CCC at BBCH 30–31 + ethephon (ET) at BBCH 37–39; CCC at BBCH 30–31 + trinexapac-ethyl (TE) at BBCH 37–39. All the application methods of PGRs resulted in the shortening of the second internode, and the sequential application of CCC with ET or TE also resulted in the shortening of the third internode. In each PGR treatment, the lodging index in the plant (canopy height to tiller length ratio) was higher than that of the control. PGRs had a beneficial effect on the seed yield. The greatest increase in the seed yield was recorded after the application of CCC+TE. No interaction between PGRs and spring N fertilization rates on the seed yield of red fescue. The increase in the dose of spring nitrogen fertilizer from 40 to 70 kg N ha−1 resulted in a significant increase in yield. Seed yield of chewing red fescue cv. Dorosa was 29% higher than strong creeping red fescue cv. Nista, mainly due to an increase in the number of generative tillers.

Trinexapac-ethyl as an Alternative to Reduce Lodging and Preserve Grain Yield and Quality of Rye

Trinexapac-ethyl (henceforth referred to as trinexapac) is a growth regulator that can mitigate some undesirable vegetative growth in Poaceae plants, reducing lodging and optimizing the distribution of photoassimilates to reproductive organs. The objective of this research was to evaluate the morphophysiological and productive responses of rye cultivars and trinexapac doses applied at different phenological stages of plants. Two field experiments were performed in two different seasons. In the 2015 growing season, 8 doses of trinexapac were evaluated: 0, 75, 85, 100, 115, 130, 150, 200 g ha-1 of active ingredient (a.i.), applied at the plant growth stage with the 4th node visible on the main stem (GS34). In the 2018 growing season, two cultivars (IPR 89 and BRS Serrano) and five doses of trinexapac were evaluated: 0, 50, 100, 150 and 200 g a.i. ha-1, applied at the plant growth stage with the 6th node visible on the main stem (GS36). The morphophysiological, productive and qualitative characteristics of grains were evaluated. In the 2015 season, trinexapac applied to shoot plants at GS34 only have low response in decreased plant lodging from around 20% to 10%. However, in the 2018 season, the application of trinexapac on plants at GS36, resulted in lower plant height, associated with reduced lodging and better quality of rye grains. Cultivar IPR 89 showed higher values for yield components and grain quality in comparison to cultivar BRS Serrano. Reduced lodging is dependent on speed of resumption of plant height growth, and the magnitude of response to trinexapac is also stage-cultivar-dose-dependent; in rye, the best response to trinexapac was found at GS 36 in comparison to GS 34, and for IPR 89 in comparison to BRS Serrano cultivar, respectively, with a dose range from 100 to 150 g ai ha-1. In conclusion, trinexapac (around 150 g a.i. ha-1), when applied to plants at GS36, reduces plant height, reduces the lodging index and enables the harvest of high-quality grains.

Compact plant type rice has higher lodging and N resistance under machine transplanting

To identify the major factors that contribute to the difference in lodging among different rice varieties under machine transplanting and their responses to nitrogen (N), field experiments were conducted at Danyang County (a representative eco-site of the Lower Yangtze River) in Jiangsu Province, China in 2017 and 2018, 22 hybrid indica varieties (HIs), 22 inbred japonica varieties (IJs) and two indica japonica hybrid varieties (IJHs) were transplanted by machine with three N rates (N0, N150 and N300, 0, 150 and 300 kg ha–1, respectively). Lodging-related physical parameters, morphological characteristics and apparent transport rates of dry matter were examined. Significant difference in yield was observed among different types of rice, and followed by IJs<HIs<IJHs. The average lodging index (LI) of hybrid varieties (HIs and IJHs) was higher than that of the inbred varieties (IJs) with higher plant height; moreover, lower apparent export rate of dry matter resulted lower LI in IJHs than in HIs. The HIs had a large difference in the LI, which came from the difference in bending stress (BS) induced by the difference in the apparent export rate of dry matter, varieties with lower leaf angle of upper three leaves possess strong lodging resistance capacity; however, the gap among the IJs was due to the difference in the cross section modulus (Z). The LI in the IJs or IJHs increased slightly with the increased N application, and there was no lodging incidence under the high N level, which was due to the low leaf angle and barely changed under high N; there was a significant interaction between varieties (HIs) and N rates in lodging rate and LI, varieties with lower leaf angle of upper three leaves were resistant to high N. These results suggest that compact plant type rice has higher lodging and N resistance at machine-transplanting method.

Evaluation of Newly Developed Rice Lines in Lowland Ecology in Ghana

Rice is one of the major staple foods consumed in all part of the world including Ghana. The study was conducted at the research field of CSIR in Sokwai to evaluate the performance of the newly released rice varieties in lowland ecology in Ghana. The data collected were subjected to analysis of variance using Statistical Tool for Agricultural Research Version 2.0.1. The analysis of variance revealed a highly significant variation among most of the agronomic traits studied except for the panicle length, moisture content, total weight of 5 hills, the percent moisture content and the lodging index. The first five principal component (PC) accounted for 71% of the total variation with PC1, PC2 and PC3 contributing 20%, 17% and 13% respectively. The cluster analysis placed the accessions into five main clusters. The cophenetic correlation coefficient (CCC) was 0.42.

Tef (Eragrostis tef Trotter) Responses to Nitrogen Fertigation under Semi-Arid Mediterranean Climate

Eragrostis tef (Zucc.) Trotter (tef) is a small annual grain, panicle-bearing, C4 cereal crop native to Ethiopia, where it is a major staple food. The objectives of the present study were to characterize the responses of two tef genotypes to escalating nitrogen (N) levels in terms of shoot, root, and grain biomass production, N concentration and uptake, and to determine an optimum N range at which tef performance is maximized. The N was applied in the irrigation water (Fertigation) in order to provide a consistent concentration of N in the root zone. A second goal was to test the feasibility of growing tef in the hot, arid conditions of the Northern Negev Desert. Two experiments were carried out in the Gilat Research Station (Negev region, Israel), each testing two different genotypes of tef (405B and 406W), and each including five replicates for each treatment. In the winter of 2015–2016, tef plants were grown in perlite filled pots in a walk-in plastic-covered tunnel. Five different N treatments were applied through fertigation, meaning the fertilizer was applied with the irrigation water (10, 20, 40, 80, 120 mg L−1). All other nutrients were applied at the same sufficient rate. In the summer of 2016, tef plots were sown in open-field and applied with four different rates of N fertilization (0, 30, 60, 120 mg L−1). Biomass of the different plant parts, SPAD values, N, P and K concentration, and the lodging index were recorded in each experiment. The harvest index was also calculated. Optimum N fertigation concentration in both experiments was between 40 and 80 mg L−1, under which the time to flowering was decreased, and yield and grain protein concentration were optimized. Underfertilization caused a decrease in overall plant growth, whereas overfertilization caused an increase in vegetative growth at the expense of grain yield. Potassium uptake increased along with increased N availability, whereas P uptake did not. The fertilization rate will always need to take into account local soil and climate conditions. The field experiment also pointed to low harvest index as a major limitation on tef cultivation in the Northern Negev.

Nitrogen Effects on Yield, Quality and Physiological Characteristics of Giant Rice

In China, the quantity of nitrogen fertilizer applied is large, but as a consequence of a high level of loss, its utilization rate is low. Compared to common rice, the new giant rice has interesting characteristics, namely high biological yield and good efficient use of fertilizer. However, it becomes urgent to further consider the appropriate rate of nitrogen fertilizer to be applied. The giant rice varieties Feng5 and Feng6 were set up in a pot experiment and a field experiment under five doses of nitrogen fertilizers, namely, 0 kg·ha−1 (CK), 75 kg·ha−1 (T1), 150 kg·ha−1 (T2), 225 kg·ha−1 (T3) and 300 kg·ha−1 (T4). Parameters such as leaf area index (LAI), lodging index (LI), nitrogen utilization rate, photosynthesis rate and grain yield were measured. The results showed that with the increase of nitrogen dose in a certain range, LAI, plant height, the number of tillers, net photosynthetic rate (NPn), the transpiration rate (Tr), and the grain yield increased while the lodging index (LI), the nitrogen agronomic utilization rate (AE) and nitrogen partial productivity (PFPN) decreased. Additionally, with the increase of nitrogen application, the grain yield index (HI) and nitrogen contribution rate (FCRN) of rice presented a parabolic trend.

Influence of Nitrogen Fertilizer Rates and Varieties on Growth, Grain Yield and Yield Components of Tef [Eragrostis tef (Zucc.) Trotter

A field experiment was conducted to assess the influence of N fertilizer rates on growth, grain yield and yield components of Tef [Eragrostis tef (Zucc.) Trotter], in 2017 main cropping season. Three tef varieties (Kora, Boset and Asgori) and five Nitrogen rates (0, 30, 60, 90 and 120kg N ha-1) were used in Randomize Completed Block Design with three replications with the same dose of Triple Super Phosphate. The total and productive tiller number were highly (P&lt;0.01) significantly affected by varieties. The control plot had maximum days to heading and this may be due to nitrogen fixation may exist and its availability may be deficient in the soil. The less response to the N rate may be due to variability of fertility or soil N content, and genetically difference between varieties. From means of varieties, the early flowerings of Boset and Asgori varieties were 101.4 and 103.79 days to maturity, respectively, but Kora (108.9 days) was late matured. Kora had maximum plant height (135.9cm) and panicle length (56.07cm) followed by Boset (115.1cm) and (42.49cm) respectively. The lodging index was affected by N rates and Kernel weight was highly significantly (P&lt;0.01) affected only by varieties. The highest mean of thousand kernel weight (0.3387) was noted from Asgori variety. The grain yield was decreased with N rates and a better grain yield was obtained at 60-90kg N ha-1. Overall N rates indicated that, both Kora (1800) and Boset (1883) had a better grain yield in kg ha-1, but Asgori had lowest grain yield (1560kg ha-1). Based on the economic point of view, it would be more profitable to use 60kg N ha-1 N rates.

Biomechanical Properties and Agro-Morphological Traits for Improved Lodging Resistance in Ethiopian Teff (Eragrostis tef (Zucc.) Trottor) Accessions

Susceptibility to lodging is a major constraint on teff production in Ethiopia, but efforts to develop lodging-resistant cultivars have not been successful. We studied the mechanical properties of teff culms and associated agro-morphological traits in field experiments with 320 teff accessions at two sites in northwestern Ethiopia during the 2018 and 2019 growing seasons. The results showed significant variability in both mechanical properties and agro-morphological traits among accessions. Traits contributing to lodging resistance, such as internode diameter, pushing resistance, and base failure moment, were significantly positively correlated with each other and with plant height. Similarly, the correlation of those traits with lodging index was significant and positive. In contrast, tiller number showed a significant negative correlation with lodging index. The peduncle–panicle length, which generally accounted for 59% of the plant height, should be a target when breeding for semi-dwarfism. Root system development, which reached a depth of more than 1 m in tall and 57 cm in dwarf teff accessions, signifies the presence of genetic variabilities for future root lodging studies in teff, and it may also explain why teff performs well in drought-prone areas of Ethiopia. Breeding programs for lodging resistance might focus on accessions with good standing ability (high base failure moment) and introgression of stem strength with a semi-dwarf phenotype. Alternatively, selection for a large internode diameter, increased pushing resistance and base failure moment, and a reduced tiller number should be considered.

English

Forty-nine tef, Eragrostis tef (Zucc.) Trotter, genotypes comprising 36 improved and 10 farmers&rsquo; varieties, and, three elite breeding lines were field evaluated using 7 &times; 7 simple lattice design at two contrasting locations (Debre Zeit and Alem Tena) in central Ethiopia during the main cropping season. The objective was to assess the extent and pattern of genetic diversity for 23 quantitative pheno-agro-morphological traits. Differences among the varieties were significant for most of the traits except lodging index, thousand seed weight, plant weight and grain yield per plant at each location. Similarity, the pooled analysis over locations showed significant genotype effect for most of the traits except number of total and fertile tillers, lodging index, plant weight and grain yield per plant. The varieties were grouped into seven clusters of different sizes. Improved varieties resulting from direct selection and hybridization were clustered together while local varieties mostly remained solitary. Principal component analysis depicted cumulative effects of a number of traits resulted in the differentiation of the varieties into clusters. Genetic distances among most of the clusters were significant such that crosses between parents selected out of them are expected to generate desirable genetic recombination. Hence, incorporation of farmers&rsquo; varieties in the breeding program would be imperative for broadening the genetic base of the released varieties. Moreover, future research strategies on germplasm collection, conservation, rejuvenation, characterization, selection and incorporation must be given due emphasis in the tef breeding program. Key words: Clustering, genetic diversity, improved varieties, farmers&rsquo; varieties, pheno-agro-morphological traits, principal component analysis, tef. &nbsp

Optimization of plant density and nitrogen regimes to mitigate lodging risk in wheat

AbstractInfluences of planting density and nitrogen rate have been investigated frequently in targeted wheat (Triticum aestivum L.) research. Few studies have investigated interactions between these inputs. The objective was to determine the combine effect of N and seeding rates on culm morph‐physiological traits for lodging tolerance and grain yield. The experiment used a split‐split randomized block design using two wheat varieties ‘AnNong0711’ and ‘YanNong19’, split by four seeding (180, 240, 300, and 375 × 104 ha−1) and four N rates (0, 180, 240, and 300 kg ha−1). Lodging traits of plant height, culm height center of gravity, and internode length, increased (p &lt; .05) however, stem diameter, wall thickness, and stem breaking strength decreased with increasing N and seeding rate. Stem breaking strength was negatively correlated with culm height center of gravity (r = −.869, p = .01), internode length (r = −.872, p &lt; .01), and lignin (r = −.746, p &lt; .01) but positively correlated with internode diameter (r = .715, p &lt; .05) and wall thickness (r = .696, p &lt; .05). Culm lodging index and cellulose showed positive correlation (r = .807 and .913 respectively) with lignin. Compared to YanNong19, AnNong0711 showed higher grain yield and culm lodging index of 9 and 20.49%, respectively. For improved grain yield, 180 plants m−2 was optimal in surface combinations with 210 kg N ha−1 for AnNong0711 and 200 kg N ha−1 for YanNong19. These combinations of seeding and N rates could successfully mitigate lodging and improve grain yield.

Less Is More: Lower Sowing Rate of Irrigated Tef (Eragrostis tef) Alters Plant Morphology and Reduces Lodging

Tef (Eragrostis tef (Zucc.) Trotter) is a panicle-bearing cereal crop plant, originating from and grown mainly in Ethiopia. Tef yields highly nutritious gluten-free grain as well as high-quality forage, therefore, interest is rising regarding tef cultivation for grain and forage outside Ethiopia. Lodging is a major factor limiting tef quality and yield, with losses estimated at 30%–35% and presumably higher under mechanical harvest. Studies in other cereal crops suggested that lowering plant density would lead to sturdier plants less prone to lodging. In this work, we reported on the effects of sowing rate on lodging, lodging-related traits, and productivity of tef under irrigated conditions. Four tef genotypes were grown under irrigation across two years at three sowing rates: low (3 kg/ha), medium (6 kg/ha), and high (common, 9 kg/ha). Grain yield and biomass did not differ significantly among sowing rates. The visually assessed lodging index (LI) increased as the season progressed, with the lowest values recorded under low sowing density. A significant difference in LI values among the tested genotypes suggested potential for crop improvement. Aerial RGB images of the field taken by an unmanned aerial vehicle twice during the second season produced a high-resolution crop surface model, which was used to assess lodging. Aerial-based LI values were significantly correlated with the ground-based ones and exhibited better capacity to identify minor differences in lodging. Among the morphological traits assessed, crown diameter, crown root number, and crown root diameter were significantly affected by sowing rate and genotype and were correlated with LI values. In summary, this study demonstrated for the first time the feasibility of tef production under irrigated Mediterranean conditions and the potential of a reduced sowing rate as a remedy for lodging.

The Response of Teff [Eragrostis teff (Zucc) Trotter] to Nitrogen Fertilizer Application and Row Spacing: A Review

Teff [ Eragrostis tef (Zucc) Trotter] is one of the most important crops in Ethiopia. It ranks the first among cereals in the country in area coverage and second in the production volume. Despite its importance, the production and productivity of this particular crop are highly constrained by several biotic and abiotic factors. Some of the factors contributing to the low yield of teff are low soil fertility and suboptimal use of mineral fertilizers in addition to weeds, old method of seed sowing, erratic rainfall distribution in lower altitudes, method of row planting, lack of high yielding cultivars, lodging, water-logging and late planting of the crop which exposes it to moisture stress. The productivity of teff is very low compared to other major cereal crops. On the other hand, under conditions where most growth requirements are available and inorganic matter rich soils, the application of fertilizers without knowing its fertility status causes yield and fertilizer losses. Likewise, producers do not give attention to teff row spacing, even if it has an advantage of shorter maturity days, highest plant height, highest panicle length, and the number of tillers and less lodging index percentages. Since, grain yield increased with the increase of plant height, panicle length and number of tillers per plant. Therefore, the optimum supply of nitrogen fertilizer and medium row spacing increased the grain yield of crops. Keywords: teff; inter-row spacing; and grain yield DOI : 10.7176/ALST/78-02 Publication date: February 29 th 2020

Genetic progress in stem lodging resistance of the dominant wheat cultivars adapted to Yellow-Huai River Valleys Winter Wheat Zone in China since 1964

Analysis of genetic progress for lodging-related traits provides important information for further improvement of lodging resistance. Forty winter wheat cultivars widely grown in the Yellow-Huai River Valleys Winter Wheat Zone (YHWZ) of China during the period of 1964–2015 were evaluated for several lodging-related traits in three cropping seasons. Plant height, height at center of gravity, length of the basal second internode, and lodging index decreased significantly in this period, and the average annual genetic gains for these traits were −0.50 cm or −0.62%, −0.27 cm or −0.60%, −0.06 cm or −0.63%, and −0.01 or −0.94%, respectively. Different from other traits, stem strength showed a significant increasing trend with the breeding period, and the annual genetic gains were 0.03 N or 0.05%. Correlation analysis showed that lodging index was positively correlated with plant height, height at center of gravity, and length of the basal second internode, but negatively correlated with stem strength. Meanwhile, significantly positive correlations were observed between plant height, height at center of gravity, and length of the basal first and second internodes. By comparison with the wild types, dwarfing genes had significant effects on all lodging-related traits studied except for length of the basal first internode and stem strength. Principle component analysis demonstrated that plant height and stem strength were the most important factors influencing lodging resistance. Clustering analysis based on the first two principle components further indicated the targets of wheat lodging-resistant breeding have changed from reducing plant height to strengthening stem strength over the breeding periods. This study indicates that the increase of stem strength is vital to improve lodging resistance in this region under the high-yielding condition when plant height is in an optimal range.

The role of ridge‐furrow with plastic film mulching system on stem lodging resistance of winter wheat in a dry semi‐humid region

AbstractRidge‐furrow with plastic film mulching (RFPFM) is widely used as a water‐saving strategy for the improvement of crop yield. However, lodging susceptibility under RFPFM practices has not yet been determined. A 2‐yr field study comprising of three cultivation strategies (rain‐fed flat planting [FP], RFPFM, and well‐water planting [WW]) and two N application rates (75 and 225 kg N ha–1) was conducted to assess the risk of lodging and the relationship between lodging resistance and grain yields of two wheat (Triticum aestivum L.) varieties (Xinong979 as lodging resistant and Xiaoyan22 as lodging susceptible). The results showed that higher N application increased lodging index under FP and RFPFM, and the lodging index was 33% lower under RFPFM than under WW. In both years, there was a positive relationship between grain yield and lodging susceptibility (R2 = 0.62** and 0.57**) implying that promoting crop yield by using RFPFM strategy accelerates the risk of lodging. When compared with WW, RFPFM significantly reduced the lodging index, while sustaining a comparable grain yield. Overall, RFPFM could be highly recommended as a promising strategy for winter wheat producers in dry, semi‐humid regions. The close relationships of breaking resistance and lodging index with both mass density and stem wall thickness of basal internode suggest that selection for increased stem strength trait could lead to improved lodging resistance and higher yields in future programs for winter wheat cultivar improvement.

Lactofen and kinetin in soybean yield

ABSTRACT The herbicide lactofen has been used by producers in many conditions, in order to increase the soybean yield. This study aimed to evaluate the influence of lactofen and the phytohormone kinetin on the morpho-agronomic traits, carbohydrate partitioning and yield, in soybean cultivars. Three experiments were carried out in the field, in addition to one experiment in a greenhouse. A randomized block design, with four replications, was used. The treatments were: lactofen [144 g ha-1 of active ingredient (a.i.)], lactofen + kinetin (144 g ha-1 of a.i. + 0.5 g ha-1), kinetin (0.5 g ha-1), manual cutting of apical buds and control. In the subplots, six soybean cultivars (M 6410 IPRO, M 5917 IPRO, NS 7670 RR, NS 6909 IPRO, BMX Lança IPRO and Produza IPRO) were used. In the field, the plant lodging index, plant height, number of nodes and branches, pods and grains per plant, mass of 100 grains and grain yield were evaluated. In the greenhouse, the starch, reducing sugars, sucrose and total sugars in the leaves, stems and roots of three soybean cultivars were quantified. The application of lactofen in the V6 stage influenced the morpho-agronomic traits of the cultivars in the field and increased the soybean yield by 312 kg ha-1, considering all the cultivars. The phytohormone did not influence the morpho-agronomic traits neither the grain yield. The treatments did not induce modification in the partitioning of carbohydrates destined to the roots.

Effects of Nitrogen Fertilizer Rate and Inter-row Spacing on Yield and Yield Components of Teff [Eragrostis teff (Zucc.) Trotter] in Limo District, Southern Ethiopia

Teff [Eragrostis tef (Zucc.) Trotter] is the main staple food of Ethiopia. It ranks the first among cereals in the country in area coverage and second in the production volume; however, its productivity is almost stagnant. The Quncho (Dz-Cr-387) teff variety was sown during the main cropping season of 2017 at the Limo District, Southern Ethiopia. The objective of this research was to study the effect of four nitrogen fertilizer rates (0, 32.5, 65 and 97.5 kg N/ha) and three inter-row spacings (15, 20 and 25 cm), to evaluate the effects on yield and yield components of teff and to identify the economically appropriate nitrogen rates and inter-row spacing that maximize the yield of teff. A factorial experiment was laid out in Randomized Complete Block Design (RCBD) with 12 treatment combinations and three replications. Phenological and yield-related parameters were measured. The main effects of N rate and inter-row spacing showed significant differences (P≤0.05) for all yield and yield components. The effects of N rate by inter-row spacing interaction were not significant for some traits except for the lodging index, biomass yield, grain yield, and straw yield and harvest index. Application of N rate at 97.5 kg/ha and inter-row spacing with 25 cm significantly (P≤0.01) increased grain yield of teff. Moreover, both N fertilizer rates and wider inter-row spacing increased the magnitudes of the important yield attributes including plant height, panicle length, number of effective tillers per plant, thousand seed weight, biomass yield and straw yield significantly (P≤0.01) and also inter-row spacing increased the magnitudes of important yield attributes significance (P≤0.05). From the results of the study, it is possible to conclude that increased application of nitrogen fertilizer rate and row spacing improves yield and yield components of teff. Therefore, the application of 97.5 kg N/ha and inter-row spacing of 25 cm gave maximum yield which can be recommended for the study area.

The effects of seeding rate on yield, lodging resistance and culm strength in wheat

ABSTRACT We compared the effects of four seeding rates, 60, 100, 140, and 180 seeds m−2, on yield, lodging resistance and culm strength using two Japanese wheat cultivars Ayahikari and Iwainodaichi. With the decreasing seeding rate, maximum tiller number decreased, percentage of productive culms increased and spike number m−2 decreased, and the spikelet number per spike, percentage of fertile spikelets, grain number per spikelet and grain number per spike increased. Consequently, grain yield was not significantly affected. Lodging was not observed, but the lodging index was significantly affected by the seeding rate and was the highest in the plots sown at 180 seeds m−2. The bending moment at the breaking point and flexural rigidity of the basal internode with leaf sheaths were highest in the plots sown at 60 seeds m−2. In conclusion, the culm strength and stem lodging resistance increased with decreasing seeding rate. Section modulus and bending stress, which constitute the bending moment at the breaking point, and the moment of inertia area and Young’s modulus, which represent the flexural rigidity, were highest in plots sown at 60 seeds m−2. Therefore, the seeding rate was considered to influence the culm morphology and functions of the cell wall components. The effects of the seeding rate on culm characteristics and lodging resistance did not differ between the two cultivars, and ‘Ayahikari’ had consistently stronger culms than ‘Iwainodaichi’. We suggest that low seeding rates method would be suitable for heavily fertilized cultivation for both cultivar with high and low culm strength. Abbreviations AMeDAS: the automated meteorological data acquisition system; HSD: honestly significant difference