Significant Yield Variation Research Articles

Ecological Factors Regulate Essential Oil Yield, Percent and Compositions of Endemic Yarrow (Achillea eriophora DC.) in Southeast Iran

Endemic yarrow (Achillea eriophora DC.) has been widely used in folk medicine for centuries. The impact of climatic and edaphic conditions was investigated on essential oil (EO) yield and compositions of different yarrow ecotypes, native to Kerman province in southeast of Iran. The aerial part of plants was collected from 13 naturalhabitats. Gas chromatography-mass spectrometry (GC-MS) analysis revealed a significant variation in EO yield and compositions among ecotypes. 116 components were identified from 13 regions. EO extraction yields fluctuated from 0.71 to 5.83% (v/w) in KP12 and KP02 regions, respectively. The predominant components were L-borneol (0-45.93%), bornyl acetate (0-22.45%), bornyl ester (0-10.46%), (E)-α-ionol (0-28.77%), 6βBicyclo [4.3.0] nonane5β-iodomethyl-1β-isopropenyl-4α, 5α-dimethyl (0-12.14%) and eucalyptol (0- 3.96%). For the first time, the presence of hexadecenoic acid, 6β-bicyclo [4.3.0] nonane and 5β-iodomethyl-1β-isopropenyl-4α, 5α-dimethyl were reported in A. eriophora. EO yields and compositions were affected by the ecological factors. Among them, soil pH and latitude showed the most significant impacts.

Yield and Physiological Response of Common Bean in Three Semi-Commercial Farmers’ Fields in Limpopo Province

Despite the importance of common bean (Phaseolus vulgaris) in human nutrition, its production in developing countries is far below consumption rates. A study was established to understand the yield performance and physiological response of common bean under three farmers’ field in the Limpopo Province. The results revealed significant variation in grain yield and biomass between the locations. Physiological parameters such as the Normalised Difference Vegetation Index (NDVI), Leaf Area Index (LAI), SPAD value and leaf gas exchanges were strongly influenced by the location, the crop growth stage and crop management. Dry bean crop performance was significantly lower at Masemola. Grain yield at Masemola was 30% less than that achieved at Dalmada and Mokopane. NDVI and LAI were also consistently lower at Masemola when compared to the other locations. This study revealed that poor yields by emerging farmers in dry areas are due to poor agronomic and irrigation management.

Thermochemical Conversion of Napier Grass for Production of Renewable Syngas

Fuel resource diversification is a global effort to deviate from non-renewable fossil fuels. Biomass has been identified as an alternative solid biofuel source due to its desirable properties and carbon neutrality. As reported in the literature, biomass can positively contribute towards combating climate change while providing alleviation for energy security issue. As part of efforts to diversify biomass resources, this work intends to explore the potential of Napier grass, one type of energy crop, for the production of renewable syngas via gasification. This energy crop is originally from Africa, which is highly productive with low cost (40 tonnes per year per hectare). Limited studies were conducted to analyze the potential of such an energy crop as a fuel source, which is the subject of this work. In order to analyze the full potential of such energy crop, the physical and chemical characteristics of this biomass was first analyzed. To determine the productivity of syngas from this biomass, fluidized bed gasifier was used in this work. The effects of gasification process parameters (i.e., equivalence ratio and temperature) on product yield and producer gas compositions were examined. Besides, the effects of equivalence ratio towards higher heating value of syngas and carbon conversion efficiency were analyzed. Based on the ultimate analysis results, the molecular formula of Napier gas was CH1.56O0.81N0.0043. Meanwhile, the higher heating value of such biomass was determined as 16.73 MJ/kg, which was comparable to other biomasses. It is noted that in this work, the volatile matter was determined as 85.52% and this promoted gasification process remarkably. The dynamics of the reactions involved were observed as a significant variation in product yield and biogas components were recorded at varying equivalence ratio and gasifier operating temperature.

Effect of Nano Calcite Foliar Fertilizer on the Growth and Yield of Rice (Oryza sativa)

Purpose: Around the world nano calcite (NC) is used as an environmental friendly foliar fertilizer to enhance yield of many crops. In Sri Lankan context this fertilizer has not yet been tested for crops. Therefore, this study examined the effect of foliar application of NC on yield, yield components, seed quality and insect resistivity of rice and the interaction effect of NC foliar fertilizer with different rates of soil added fertilizer.Research Method: Field experiments were conducted in 2015/2016 Maha and 2016 Yala seasons at the Regional Rice Research Institute, Ambalanthota, Sri Lanka. The rice variety used for the study was At 362. Four levels of nano calcite (0, 50, 100 and 150ppm) with 3 levels of soil added fertilizers (recommended fertilizer mixture, 25% over and above the recommendation) were tested. Data was collected at 30, 60 and 90 days after transplanting and at the harvesting.Findings: It was found that the application of nano calcite foliar fertilizer has positive effects on growth, yield, seed quality and insect resistivity. Hundred ppm nano calcite treatment with recommended soil added fertilizer could increase the final yield approximately about 1 ton/ha. Twenty five percent reduction or increment of soil added fertilizer than the recommended level with the application of nano calcite foliar fertilizer did not showed any significant yield variation. However, higher concentrations of nano calcite greatly reduce the pest damages to the crop.Originality/ value: Results of the experiment revealed that nano calcite foliar application can increase rice yield to a certain extent. However, further experiments need to be done to ensure the sustainability of the application.

Yield and yield components of local cowpea (Vigna unguiculata L.) landraces grown in mixed culture with maize (Zea maysL.) in vertic cambisols in the Northern part of Tanzania

Smallholder farmers in the North eastern Tanzania practice cereal-legume mixed culture to manage risks of crop failure in sole crops. The production and productivity of cereal-legume intercrops may be influenced by the practice of cultivating two or more crops in the same space and time and the status of land races/cultivars involved as intercrops. Data on the effect of intercropping system on cowpea landraces with maize grown on Vertic Cambisols on yield and yield components are inadequate in the North eastern Tanzania although considerable knowledge has been accumulated on mixed culture system. A field experiment involving two cropping systems (sole crop and intercropping) was therefore conducted for two years (2017 and 2018) at Shirimatunda village, Kilimanjaro Region, North East Tanzania, to evaluate three local cowpea (Vigna unguiculata L.) landraces (i.e. landrace 1 (L1), landrace 2 (L2) and landrace 3 (L3)) grown in association with maize (Zea mays L). Intercropping significantly (P≤.05) decreased cowpea and maize yields. Performance of local cowpea landraces, however, did not show (P≤.05) any variation except for 100–seed weight where cowpea landrace 2 (L2) showed superiority compared with the other cowpea landraces. Although there was no significant variation in maize yield when intercropped with cowpea landraces, maize intercropped with cowpea landrace 1 gave numerically the highest grain yield. Regardless of cropping system and cowpea landraces, combined productivity of cowpea and maize increased in the intercropped plots as indicated by higher total land equivalent ratios (1.64 to 1.94). Highest LERT value was observed in the ‘Cowpea landrace 1’+Maize mixed culture. The observed total Land equivalent ratio (LER) values correspond to 48.25, 38.54 and 43.66 % of lands saved which could be used for other agricultural purposes. In these cropping systems, both cowpea landrace 1 & 3 and maize crop components were significantly complementary and most suitable in mixed culture as shown by competitive ratio (CR) values of 1.85 and 1.45 respectively.

Genetic variability and inter species relationship between wild and cultivated yams (Dioscorea spp.) from Koraput, India based on molecular and morphological markers.

Wild yams (Dioscorea spp.) are important tuber crops used both as vegetable and medicine by the tribal people of Koraput, India. There is deficiency of documented information on genetic structure and diversity of wild yams and its genetic assessment is necessary for crop improvement program. The present study assessed the level of genetic diversity of eight wild and one cultivated yam species of Koraput by using different morphological and molecular markers. Significant variation in different yield and morphological traits was observed among the studied yam species. The major morphological traits such as branch number, stem thickness, tuber depth, tuber length, number of tubers per plant and yield showed high genetic heritability accompanied with high genetic advance and major determinants of phenotypic diversity. Molecular profiling was carried out by taking five simple sequence repeat markers. A total of 10 polymorphic bands with an average of two were detected at the loci of the five markers across the nine yam species. Genetic similarity analysis revealed that some wild yam species such as D. oppositifolia, D. hamiltonii and D. pubera showed higher genetic similarity with cultivated (D. alata) species. The knowledge of the extent of genetic variations of wild yam species is important for planning of the genetic conservation and the utilization of this resource especially for genetic improvement.

Effect of soil amendment with Gliricidia sepium and Tephrosia vogelii biomass on maize yield at Makoka in Malawi

Several studies assessing the effect of leguminous tree biomass such as Gliricidia sepium and Tephrosia vogelii on maize yield have been undertaken. There has been limited knowledge on the efficacy of leguminous tree biomass on maize yield when grown after a crop with a high nitrogen (N) demand. One such crop is cotton. The current study was undertaken with the objective of determining the efficacy of either gliricidia or tephrosia biomass application with or without inorganic fertilizer on maize yield cultivated after cotton and also after land fallowing. Significant variations in grain yield (P = 0.0038) were obtained in the second cropping season (2016/17) but not in the first cropping season (2014/15), except maize stover (P < 0.0016). Significant variations were also obtained during 2016/17 season with respect to maize cob yield (P < 0.0041) and stover yield (P = 0.0062). Grain yield was significantly higher where inorganic fertilizer was applied with gliricidia biomass than where inorganic fertilizer was applied alone. A similar trend was also observed during the first cropping season though not significantly different. Lower grain yield was obtained when cotton crop preceded maize crop indicating a need for a higher N fertilizer dose for maize crop cultivated after cotton. Application of a half dose of inorganic fertilizer together with gliricidia biomass showed high and steady grain yield over the yield obtained when inorganic fertilizer was applied alone. It is concluded that soil fertility amendment with inorganic fertilizer is needed after a cotton crop. Also, the use of a half dose of inorganic N fertilizer with gliricidia was effective, suggesting that a full dose with gliricidia biomass was rather surplus to the requirements for maize production. Our study shows that farmers can save nearly half of the inorganic N fertilizer required by maize under gliricidia-maize system.

Effect of Different Levels of Nitrogen &amp; Phosphorus Fertilizer and Roguing on Seed Production of Rice in Bangladesh

An experiment was conducted at the Farmer’s Field, Boyra village, Mymensingh, Bangladesh during the period from February to May 2016 to study the yield performance of boro rice for seed production as influenced by nitrogen and phosphorus fertilization with different levels of roguing. The experiment comprised three levels of roguing viz. no roguing (R0), roguing one time (R1) and roguing two times (R2) and five doses of N and P fertilizers viz. Farmer practice (F1: 250 kg urea and 260 kg TSP), Optimum/recommended (F2: 187 kg urea and 200 kg TSP), High N (F3: 200 kg urea and 200 kg TSP), High P (F4: 187 kg urea and 240 kg TSP) and High N + High P (F5: 200 kg urea and 240 kg TSP). The experiment was laid out in a randomized complete block design with three replications. Results revealed that the Optimum doses of fertilizer applications significantly produced the highest grain yield among the treatments. All the yield contributing characters showed the best performance in this treatment. Though roguing did not produce significant yield variation but the interaction effects did. Here, The Optimum doses of fertilizer without roguing (F2R0) produced highest grain yield but it was at per with F3R1, F2R2, F2R1, F4R1 and F5R2 treatments. Among the five statistically alike treatments F2R2 i.e. optimum fertilizer dose with two rougings produced the highest number of filled grains per panicle and highest seed germination and appreciably higher percentage of pure seed. Based on this experimental result, it appears that optimum fertilizer dose with two times rouging treatment performed the best for seed production in BRRI dhan29.

Phenology of Sclerocarya birrea (A. Rich.) Hochst. Provenances

Phenology study was conducted to assess 22 genotypes of Sclerocarya birrea (A. Rich.) Hochst, collected from West, Eastern and Southern Africa. Assessments were done on time for bud onset, flower opening, leaf flush, fruit set, fruit maturity period and fruit production. Highly significant (P&lt; 0.001) variations between provenances were obtained in all the phenological traits assessed including variations between sexes in time from flower bud set to anthesis. There was flowering overlaps and synchrony between provenances and sexes with males flowering earlier than females. So far two subpopulations have emerged within the trial referred to as early and late flowering genotypes. The early flowering included provenances from Mozambique, and Swaziland while the late flowering encompassed provenances from Malawi, Zimbabwe, Namibia, Tanzania and Zambia. Fruit maturity period ranged from 76±2 to 192±15days. The early flowering genotypes flowered, fruited and matured between August and January while the late genotypes flowered and fruited from September to May. There were highly significant (P≤0.001) variations in fruit yield of S. birrea provenances between 2016/2017 and 2017/2018 seasons with the former being more productive than the later confirming that S. birrea fruit yield is not constant across seasons due to seed mating effects. There were very strong positive relationship ranging r=0.81 to r=0.78 between leaf flush, bud set, flower opening and fruit set significant at (P&lt;0.001). Some trees classified as females in the first year as based on flowers were found have male flowers which calls for more detailed investigations into this sex change behaviour.

Drought tolerance indices for selection of drought tolerant, high yielding upland rice genotypes

The purposes of this study were (1) to assess the effectiveness of drought tolerance indices for selection of drought tolerance in upland rice, and (2) to identify the most suitable drought tolerance indices to select for drought tolerant, high yielding upland rice genotypes. This study employed a Split Plot design consisting of irrigation levels as the main plots, and rice genotype as the sub-plot treatments. There were three main plots: 100% field capacity (FC); 75% FC; and 50% FC level. The subplot treatments consisted of 40 upland rice genotypes. Grain yields under no-stress and stressed conditions were used to calculate drought tolerance indices. There were significant variations in grain yields and drought tolerance indices between different rice genotype treatments. The indices from the literature found to be most suitable for the selection of drought tolerant upland rice cultivars were STI, GMP, MRP, HARM, REI, ATI, YI, SNPI. Ten genotypes from among the 40 tested - namely HK-07, ADN-04, PMK-01, ADN-05, NGR-022, ALR-02, HK-06, and KMD-01 - were selected as combining drought tolerance with high yield potential.

Variation in nitrogen use efficiency of winter wheat

Optimization of nitrogen fertilization to specific cultivar requirements is a major objective for improvement of trade-offs between grain yield, environmental sustainability and maximum profitable production. The aim of this study was to assess the effects of nitrogen fertilization on grain yield, and nitrogen use efficiency of modern wheat cultivars in different growing seasons. The trials with eight winter wheat cultivars and seven top-dressing nitrogen treatments were carried out in three successive growing seasons under rain-fed conditions of the southern Pannonian plain. The results from our study showed a significant variation in grain yield and nitrogen use efficiency among winter wheat cultivars when grown under different environmental and soil nitrogen level conditions. On average, grain yield ranged from 4961 to 6375 kg ha-1 among winter wheat cultivars. Increase of N soil level resulted in significant grain yield increase and nitrogen use efficiency decrease compared to the control. In 2015/16, 2016/17, and 2017/18 growing seasons grain yield of winter wheat cultivars reached plateau at 156, 175, and 128 nitrogen soil level, respectively. Significant influence of cultivar by nitrogen fertilization interaction indicated that it is necessary to adjust nitrogen fertilization to each cultivar. Moreover, notable weather variability between different growing seasons is a major limiting factor for optimal nitrogen fertilizer application in winter wheat production under conditions of the Pannonian plain.

Effect of Seed Rate and Walkway on Yield of Field Pea Under Relay Cropping with T. Aman Rice

The field experiment was conducted at Pulses Research Centre (PRC), Ishurdi, Pabna and Regional Agricultural Research Station (RARS), Jamalpur during rabi 2012-2013 to find out the effect of seed rate and walkway for green pea production as relay cropping with transplanted Aman rice. The experiment was based on six seed rates @ 50, 60, 70, 80, 90 and 100 kg ha-1 and two walking ways viz. 15 cm wide walkway at 2 m interval over the plot and control with three replications. A local cultivar of pea, named Natore was used in this trial. Results revealed that the treatment with 100 kg seed ha-1 gave the highest pod yield of 5.13 t ha-1 and 4.98 t ha-1 at Jamalpur and Ishurdi locations, respectively which was similar to 80 (S4) and 90 (S5) kg seed ha-1.. Walkway had no significant variation in yield and yield contributing characters but it produced the higher yield over the control. Using walkway, 100 kg seed ha-1 (S6) and 15 cm walkway at 2 m interval over the plot (W1) produced the highest pod yield of 5.14 t ha-1 and 4.95 t ha-1 and fodder yield of 6.70 t ha-1 and 6.13 t ha-1 at Jamalpur and Ishurdi locations, respectively. Maximum gross margin of Tk. 1,06,040 ha-1 and Tk. 1,02,401 ha-1 was contributed by combinations of using 100 kg seed ha-1 and 15 cm walking way but maximum benefit cost ratio (BCR) of 3.40 and 3.43 were obtained from S5×W1 combination at Jamalpur and Ishurdi locations, respectively. It is concluded that pea cultivar can be successfully cultivated for green pod production through the use of 90-100 kg ha-1 seed with walkway of 15 cm wide in the plot after 2 m intervals.&#x0D; Bangladesh Agron. J. 2018, 21(1): 95-103

A rapid monitoring of NDVI across the wheat growth cycle for grain yield prediction using a multi-spectral UAV platform

Wheat improvement programs require rapid assessment of large numbers of individual plots across multiple environments. Vegetation indices (VIs) that are mainly associated with yield and yield-related physiological traits, and rapid evaluation of canopy normalized difference vegetation index (NDVI) can assist in-season selection. Multi-spectral imagery using unmanned aerial vehicles (UAV) can readily assess the VIs traits at various crop growth stages. Thirty-two wheat cultivars and breeding lines grown in limited irrigation and full irrigation treatments were investigated to monitor NDVI across the growth cycle using a Sequoia sensor mounted on a UAV. Significant correlations ranging from R2 = 0.38 to 0.90 were observed between NDVI detected from UAV and Greenseeker (GS) during stem elongation (SE) to late grain gilling (LGF) across the treatments. UAV-NDVI also had high heritabilities at SE (h2 = 0.91), flowering (F)(h2 = 0.95), EGF (h2 = 0.79) and mid grain filling (MGF) (h2 = 0.71) under the full irrigation treatment, and at booting (B) (h2 = 0.89), EGF (h2 = 0.75) in the limited irrigation treatment. UAV-NDVI explained significant variation in grain yield (GY) at EGF (R2 = 0.86), MGF (R2 = 0.83) and LGF (R2 = 0.89) stages, and results were consistent with GS-NDVI. Higher correlations between UAV-NDVI and GY were observed under full irrigation at three different grain-filling stages (R2 = 0.40, 0.49 and 0.45) than the limited irrigation treatment (R2 = 0.08, 0.12 and 0.14) and GY was calculated to be 24.4% lower under limited irrigation conditions. Pearson correlations between UAV-NDVI and GY were also low ranging from r = 0.29 to 0.37 during grain-filling under limited irrigation but higher than GS-NDVI data. A similar pattern was observed for normalized difference red-edge (NDRE) and normalized green red difference index (NGRDI) when correlated with GY. Fresh biomass estimated at late flowering stage had significant correlations of r = 0.30 to 0.51 with UAV-NDVI at EGF. Some genotypes Nongda 211, Nongda 5181, Zhongmai 175 and Zhongmai 12 were identified as high yielding genotypes using NDVI during grain-filling. In conclusion, a multispectral sensor mounted on a UAV is a reliable high-throughput platform for NDVI measurement to predict biomass and GY and grain-filling stage seems the best period for selection.

Identification of Favourable Testing Locations for Barley Breeding in South Pannonian Plain

The aim of this study was to identify desirable, and also non-informative or highly correlated locations using GGE biplot. In this study, ten barley genotypes were tested across five locations for two growing seasons in official state trials performed by the Ministry of Agriculture, Forestry, and Water Management of the Republic of Serbia. In both growing seasons, environment had the highest influence on barley yield, explaining 77.70% in 2010/11 and 86.41% in 2011/12 growing season of the total variation. A significant grain yield variation explained by environmental effects indicated that the environments tested in our study were highly diverse. Together, PC1 and PC2 amounted 86.03% and 66.91% of the genotype and genotype × environment interaction sum of squares, in 2010/11 and 2011/12, respectively. The results indicate that Rimski sancevi was most favorable location and should be used for further multi-location trials while location Sremska Mitrovica was the least informative and it can be excluded from further trials. Excluding one of two similar environments could save resources with minimal risk to lose important information about genotypes performance. According to the results of our study, it can be concluded that GGE biplot is useful method for environment evaluation.

Screening Cowpea Genotypes for High Biological Nitrogen Fixation and Grain Yield under Drought Conditions

Core Ideas Cowpea nodule biomass was more sensitive to water stress compared to shoot biomass. Rainfed conditions resulted in 57% decrease in N2 fixation compared to well‐watered. Inter‐seasonal variability in rainfall accounted for 58% difference in cowpea grain yield. Future increase in drought and heat stress will challenge legume productivity in many regions. In Sub‐Saharan Africa, legumes are earmarked as an integral component in building resilience to climate change and food security in smallholder farming systems. Hence, the need for continuous screening of drought tolerant legume genotypes for sustained productivity. A 2‐yr field study was conducted to identify superior cowpea genotypes with high biological nitrogen fixation (BNF), grain yield, and drought tolerance. Four genotypes, selected from a pool of 91, were grown under four moisture levels ranging from well‐watered (WW) to severe water stress (SS). Grain yield, shoot biomass, nodule mass, and BNF were determined. There was significant effect of water stress on the measured parameters. Nodule mass and BNF were more sensitive to water stress compared to shoot biomass across genotypes. Water stress resulted in 80% reduction in nodule biomass between WW and SS. As a result, cowpea genotypes grown under SS conditions fixed 57% less N2 compared to those under WW. The study also revealed significant genotypic variation in shoot biomass, grain yield, and BNF. Genotype TVu4607 was low in grain yield but performed better for BNF (71 kg N ha−1 under WW and 30 kg N ha−1 under SS). Genotype IT00K‐1263, proved to be our superior genotype with a good balance of biomass, BNF and grain yield. Our findings suggest that future water stress may significantly affect cowpea productivity, mostly its capacity to fix nitrogen. Consequently, adaptation strategies to improve drought resistance in cowpea are needed, particularly improvement of BNF under water stress.

ОЦІНКА АДАПТИВНОГО ПОТЕНЦІАЛУ СОРТІВ ПШЕНИЦІ ОЗИМОЇ (TRITICUM AESTIVUM L.) В УМОВАХ ПІВДЕННОГО СТЕПУ УКРАЇНИ

Наведено результати екологічного випробування 11 сортів пшениці озимої протягом 2012-2017 рр. в умовах Південного Степу України. Показники екологічної пластичності і фенотипової стабільності визначали за методикою Еберхарта-Рассела, а гомеостатичність і коефіцієнт агрономічної стабільності за методикою В.В. Хангільдіна. За результатами оцінки урожайності встановлено, що в середньому по досліджуваним сортам за даний період вона склала 3,59 т/га (V = 22%). Варіювання урожайності пшениці озимої по рокам знаходиться в межах від 1,88 до 5,95 т/га. Встановлено, що визначальними факторами при формуванні продуктивності є умови року (41%) та їх взаємодія з генотипом сорту (42%). Частка впливу сорту склала 16%. Отримані результати дали можливість виділити сорт Шестопалівка, який володіє високою пластичністю (bі = 0,91), стабільністю (Sd 2 = 7,39), гомеостатичністю (Hom = 12,46), має високу господарську цінність (As = 82%), тому відповідно і сформував найвищу середню врожайність за роки досліджень (4,31 т/га). Дані результати можна використовувати в подальшому для складання рекомендацій по вирощуванню пшениці озимої в Південному Степу України. Ключові слова: пшениця озима, сорт, врожайність, екологічна пластичність, стабільність, гомеостатичність, агрономічна цінність

Evaluation of brinjal varieties for yield, genetic variability and disease reaction grown as late rabi season crop in Assam

Five hybrid brinjal varieties viz., Ketan, Vijay Kiron, Utkal Green, NV2035 Sarpan Bharata and two local cultivars viz., JC-1, Longai were evaluated at Horticultural Research Station, Kahikuchi, Guwahati as late rabi crop during 2014-16. Significant variation in plant growth parameters and fruit yield as well as on bacterial wilt incidence (Ralstonia solanacearum) were shown by all the varieties.Utkal Green recorded the highest per plant fruit yield (2.32 kg/plant) leading to the maximum total marketable yield (469.66 q/ha) and longer active fruiting duration (43.70 days).It also showed resistant reaction to bacterial wilt, recording only 12.44 per cent wilt incidence as compared to other varieties where it was in the range of 34.44 to 62.22 % at 55 days after transplanting. Although, Ketan and Vijay Kiron recorded moderately higher per plant fruit yield of 1.52 and 1.47 kg/plant,respectively but their total marketable fruit production reduced substantially due to high incidence of bacterial wilt (62.22 and 57.78%, respectively).The local cultivars, JC-1 and Longai exhibited moderately resistant reaction to bacterial wilt which registered 40.00 and 34.44 % , respectively.

Foliar spray of growth regulators significantly increases trans-1,4-polyisoprene production from Eucommia ulmoides Oliver short-rotation coppice

Eucommia ulmoides Oliver produces trans-1,4-polyisoprene (TPI or Eucommia rubber), with leaves and bark as the main sources. Raw materials from short rotation coppice (SRC) cultures for TPI industrialization are a valuable option. Currently, there is a shortage of field yield data beginning from early establishment of Eucommia SRC to support TPI manufacturers. We investigated an Eucommia SRC plantation established in 2015 with application of four plant growth regulators in Mengzhou Forest Farm, China, during its first two annual rotations. By using an orthogonal experimental design, productivity related data were derived after each growing season. We observed significant variations in biomass yield and TPI productivity among the 12 dosages of 4 regulator types and control, with plants treated with brassinolide at 5 mg L−1, DCPTA at 500 mg L−1 and DTA-6 at 20 mg L−1 reaching the highest TPI productivity among treatments of 406 kg ha−1, 391 kg ha−1 and 382 kg ha−1 in the second rotation, respectively, all of which were more than 1.4 times that of the control. Foliage spray of regulators led to more and larger leaves, more bark yield, higher tree height, and higher leaf TPI content, which reflected the enhancing effects of regulators on leaf and bark biomass as well as TPI productivities in both the first and second rotations. Meanwhile, the harvest of Eucommia leaf and bark from the coppice plantation was less labor intensive than that from tall mature trees. Our study suggested that the annual rotation period and increase of TPI from Eucommia SRC by application of regulators could reduce the payback period. Therefore, we recommend the application of growth regulators to coppice Eucommia plantations beginning from the first rotation as an economic means to increase TPI production.

Validation of Aquacrop for Different Irrigation Regimes of Onion (&lt;i&gt;Allium Cepa&lt;/i&gt;) in Bontanga Irrigation Scheme

Crop water productivity models are important tools in evaluating the effect of different irrigation regime on crop yield. AquaCrop model is a crop water productivity model adopted by the Land and Water Division of FAO in the year 2009. It simulates yield response to water for herbaceous crops, and it is particularly suitable in addressing conditions where water is a key limiting factor in crop production such as in northern Ghana. The objective of this study was to calibrate the AquaCrop model for different irrigation regimes for onion (Allium cepa), to determine its effect on crop growth and yield parameters of the crop at the Bontanga irrigation scheme. To achieve these, the Randomised Complete Block Design (RCBD) was used on Red Creole onion variety. RCBD was made up of four irrigation treatment regimes, 117%, 100%, 80% and 60% crop water requirements (CWR) of onion, with five replicates. Results indicated that there was no significant variation in yield, dry bulb biomass and total biomass, but there was difference for dry leaf biomass of onion at 0.05 significance level. The AquaCrop model simulated satisfactorily the crop yield, biomass and evapotranspiration water productivity of onion. There was a strong correlation and a significant linear relation between the simulated and measured crop yield, biomass and evapotranspiration water productivity. Validation of AquaCrop model using Nash-Sutcliffe efficiency (E), Root mean square errors (RMSE) and index of agreement (d) showed that, AquaCrop model can be used to simulate CWR of bulb crops, such as onion.

Genotypic Variation and Genotype × Environment Interaction for Yield‐Related Traits in Synthetic Hexaploid Wheats under a Range of Optimal and Heat‐Stressed Environments

ABSTRACTAdaptation of wheat (Triticum aestivum L.) to high temperature could be improved by introgressions from wild relatives. The response of 137 D genome synthetic hexaploid wheats (SHWs) to high temperature was evaluated to determine their potential for wheat improvement. Field experiments were conducted in two temperature scenarios (normal sowing time [NOR] and late sowing time to expose the plants to heat stress [HS]) for 2 yr at three locations to assess the effect of terminal high temperature on yield‐related traits. High temperature stress overall led to a 46.9% reduction in grain yield and significant reductions of 25.2% in days to heading, 26.6% in plant height, 16.1% in grain number per square meter, and 18.3% in thousand grain weight. In ridge regression analysis, agronomic traits explained 8.74 to 35.2% of the variation in grain yield in the HS treatments with an average of 30.47%. In NOR treatments, agronomic traits explained 8.85 to 45.5% of the variation in grain yield, with an average of 34.5%. Days to heading was negatively correlated with grain yield in the heat‐stressed environments but did not explain significant variation in grain yield in optimal environments. Thousand‐grain weight explained the highest variation in grain yield in all environments, followed by grain number per square meter. The top ten highest grain‐yielding SHWs in the HS treatment were also tolerant to heat stress, with a heat susceptibility index ranging from 0.33 to 0.40. These SHWs could be a promising source to introduce yield‐related traits to develop high‐yielding wheat cultivars for heat‐stressed environments.