Variation In Yield Components Research Articles

Genotype-by-Trait (GT) biplot analysis and ranking of rice genotypes in salinity stress conditions

Estimation of plant tolerance values for agronomic traits, in addition to being genetically influenced, can also be influenced by the plant’s growing environment. Effective screening at the generative stage can only be carried out on land directly affected by salinity. However, the challenge lies in the fact that salinity levels vary widely on farmers’ land and are difficult to predict. The GT biplot analysis is a statistical method used in plant breeding to evaluate the performance of different genotypes based on various supporting traits. e three groups of biplots used are genotype by trait evaluation, genotype ranking analysis, and mega-environment analysis. There were differences in genotype responses based on yield component variables in each experimental environment. IRRI-IL12 and IRRI-IL09 are stable salinity-tolerant rice genotypes. IRRI-IL07 and IRRI-IL16 are adaptive in the optimum environment (L1), IRRI-IL07 and IRRI-IL10 are adaptive in the greenhouse salinity environment (L2), and IRRI-IL13 is adaptive in the salinated intrusion (L3).

RELATIONS BETWEEN THE MASS OF THE FRUITS, THE NUMBER OF FRUITS PER PLANT AND THE AGRICULTURAL YIELD IN PEPPER, WITH INCREASING SILICON DOSES

<p><strong>Background: </strong>Statistical relations between the components of agricultural yield and the yield itself after Si treatment as possible non-destructive methods are important for predicting and monitoring the harvest. <strong>Objective:</strong> To measure the relationships between the mass of the fruit, the number of fruits per plant and the agricultural yield in pepper, with increasing silicon doses. <strong>Methodology:</strong> The research was carried out at Quevedo State Technical University, Ecuador in a completely randomized design and three repetitions per treatment. The treatments used were 0, 20, 25 and 30 g potassium silicate plant<sup>-1</sup>. The variables evaluated were fruit weight, number of fruits per plant and agricultural yield at the time of harvest. Path analysis, multiple and single linear regressions, and nonlinear regressions were performed. <strong>Results:</strong> The path analysis showed a greater direct effect of the number of fruits per plant with and without the presence of silicon. Fruit weight, number of fruits per plant, and agricultural yield increased linearly with increasing silicon dose. <strong>Implications:</strong> The best adjustment of fruit weight both in the presence and absence of silicon when it is related to the yield corresponded to a non-linear model, specifically to a Hill sigmoidal function. <strong>Conclusion: </strong>Through multiple linear regression, it was shown that both yield component variables, i.e. fruit weight and number of fruits per plant, have a greater influence on agricultural yield when fertilized with silicon. </p>

Combining modeling and experimental approaches for developing rice-oil palm agroforestry systems.

Monoculture systems in South East Asia are facing challenges due to climate change-induced extreme weather conditions, leading to significant annual production losses in rice and oil palm. To ensure the stability of these crops, innovative strategies like resilient agroforestry systems need to be explored. Converting oil palm (Elaeis guineensis) monocultures to rice (Oryza sativa)-based intercropping systems shows promise, but achieving optimal yields requires adjusting palm density and identifying rice varieties adapted to changes in light quantity and diurnal fluctuation. This paper proposes a methodology that combines a model of light interception with indoor experiments to assess the feasibility of rice-oil palm agroforestry systems. Using a functional-structural plant model of oil palm, the planting design was optimized to maximize transmitted light for rice. Simulation results estimated the potential impact on oil palm carbon assimilation and transpiration. In growth chambers, simulated light conditions were replicated with adjustments to intensity and daily fluctuation. Three light treatments independently evaluated the effects of light intensity and fluctuation on different rice accessions. The simulation study revealed intercropping designs that significantly increased light transmission for rice cultivation with minimal decrease in oil palm densities compared with conventional designs. The results estimated a loss in oil palm productivity of less than 10%, attributed to improved carbon assimilation and water use efficiency. Changes in rice plant architecture were primarily influenced by light quantity, while variations in yield components were attributed to light fluctuations. Different rice accessions exhibited diverse responses to light fluctuations, indicating the potential for selecting genotypes suitable for agroforestry systems.

Effects of sowing dates and phosphorus levels on cotton growth and yield: soil analysis and implications

This study assessed the effects of sowing dates and phosphorus levels on cotton performance in Chato-Msilale village in Chato District, Tanzania. The soil analysis revealed that field exhibited slightly acidic soil with normal electrical conductivity but suffered from severe deficiencies in total nitrogen and organic carbon. The same field presents common issue of low cation exchange capacity, indicating limited nutrient-holding capacity. Furthermore, both fields displayed very low levels of total nitrogen (<0.1%), signaling a nitrogen deficiency. Available phosphorus was rated as medium (16.8 mg kg−1 soil). Trace elements fluctuated and could be managed based on specific crop requirements. The factors at different levels were: (1) sowing dates – (i) 25th November 2022, (ii) 15th December 2022, and (iii) 4th January 2023; and (2) Phosphorus levels – (i) control, (ii) 20 kg P ha−1, (iii) 40 kg P ha−1, and (iv) 60 kg P ha−1. Regarding cotton growth and yield, sowing dates significantly (p < 0.001) influenced plant height, gin turnout, lint yield, number of bolls per plant, and boll weight while phosphorus levels did not exhibit significant effects. Earlier sowing dates resulted in higher yields, albeit with variations in yield components. Interactions showed that growth and yields were only numerically higher in the middle sowing date at higher levels of phosphorus applied. Overall, these insights offer valuable guidance for optimizing cotton cultivation in Chato District, emphasizing the importance of selecting appropriate sowing dates for improved yields.

Genotype-environment interaction in maize hybrids: a multivariate relationship between yield components, morphological variables and disease tolerance

ABSTRACT Knowledge of phenotypical variables, yield and susceptibility to diseases may clarify why some hybrids are more productive than others. In this study, we evaluated the stability and responsiveness of genotype-environment interactions on phenological variables, yield components and susceptibility to diseases of maize hybrids. Experiments were conducted in 5 regions in the Brazilian Midwest. Two population were used for each hybrid in each region, totalling 10 systems-environments. Data were analysed by Restricted Maximum Likelihood; Best Unbiased Linear Prediction and Principal Components Analysis. Environmental conditions and plant populations affect the yield components of maize hybrids. Variations equal to 57,000 and 62,700 plants ha−1 was relatively small and may not have been large enough to reveal plant density effects on disease. Diseases reduced the yield of hybrids with greater susceptibility to these phytopathogens at some sites, despite the use of fungicides. The best performance for at least two yield component variables resulted in the highest yield. Microclimate control using plant populations was omitted as a management option for reducing the severity and incidence of diseases for the tested conditions in this work. The climatic conditions of agricultural sites increased the incidence and severity of diseases, mainly of Cercospora zeae maydis.

Genetic diversity and distinctiveness of Chilean Limachino tomato (Solanum lycopersicum L.) reveal an in situ conservation during the 20th century

Landraces constitute a valuable genetic pool of increased diversity that can be exploited for agriculture sustainability, food security, food quality, and future yield increments. It also contributes to understanding a species’ origin, domestication, population dynamics, and diversity. Chilean tomato germplasm characterization and documentation are scarce. To elucidate its potential and distinctiveness, we assessed the genetic variability between and within accessions of tomato landraces grown in Chile between 1938 and 2016, determining the relationships between them and with some European and US heirloom varieties. For this purpose, the tomato plants were characterized using 72 descriptors for vegetative and reproductive morphology. In addition, molecular diversity and the determination of genetic patterns between tomato accessions were made using highly informative SSR markers. Our results indicate that the genetic structure among evaluated accessions is associated with differences between the Chilean landraces grown to 1938 and cultivars grown in Europe and USA. The Chilean cluster presented a high variability. The Limachino tomato landrace is close to Marmande but distinguishable on phenotype and the molecular basis for its private alleles, being grown in the territory of Limache before 1960 until the present day. Accessions of pink beefsteak tomato grown in Chile to 2015 are distant to the rest of the tomato accessions on morphotype and close in SSR genotype to the materials grown in Chile in 1938, supporting the hypothesis of a pre-green revolution tomato diversification in Chilean territory. Chilean tomato populations may impact breeding programs due to higher variability in yield components. Our results are consistent with other researchers that have proposed Mesoamerica and the Andes Region as tomatoes’ primary center of diversity.

Yield and yield components of superior cocoa (Theobroma cocoa L.) clones rejuvenated by ring budding technique

The ring budding technique gave a higher suitability for rejuvenation of cocoa plants compared to side cleft grafting it can be combined with the use of superior clones for optimal production. However, information related to this is still limited. The research aimed to determine the effects of ring budding technique on yield components and yields of three types of superior cocoa clones. The experiment was arranged in a Nested Design. The first factor is the type of vegetative propagation technique, consisting of side cleft grafting and ring budding. The second factor was clones, which consisted of clones KKM 22, RCC 70 and RCC 71. Clones were nested in vegetative propagation. The research was conducted from September 2020 to January 2021 at the Pagilaran Company. Observations were made on several yield component variables. The data were analyzed using Analysis of Variance (ANOVA) and continued with the Least Significant Difference Test (LSD) at the 5%. The results showed that the number of pods and the weight of beans per cocoa stand were significantly higher in the ring budding technique than the side cleft grafting. This condition caused the dry bean weight per hectare much higher as well. The three cacao clones, which were rejuvenated by ring budding, gave a good response and high yields. Meanwhile, only KKM 2 gave good response and high yield after treated with side cleft grafting technique, while RCC 70 and RCC 71 clones gave low yields. The KKM 22 clone is the best option in terms of rehabilitation with ring budding and side cleft grafting.

Variability of yield components in winter wheat varieties and breeding lines under environment of Ukrainian Forest-Steppe

Topicality. The main task of winter wheat breeding is to increase productivity, therefore, the development and introduction of new varieties of winter wheat with high productivity potential being well adapted to changing growing conditions into agricultural production is an urgent area of research. Breeders' efforts are aimed at developing varieties with a successful combination of high parameters of all the main productivity elements in one genotype, which will maximise grain yield. Breeding work is determined by many factors, among which the search and development of new genetic sources with high performance indicators. Therefore, the peculiarities of yield potential realization and the study of the mechanisms of productivity element formation under changing meteorological conditions are important for establishing the response rate and selecting the most stable productive genotypes and their further involvement in breeding programs. Purpose. To identify the best varieties and breeding lines of winter wheat in terms of productivity elements in the environment of the Forest-Steppe of Ukraine for their involvement in crossbreeding programmes. Methods. Visual – phenological observations; laboratory-field – determination of biometric indicators; mathematical and statistical – establishing the reliability of the obtained data. Results. It was found that the maximum realisation of the yield potential of winter wheat plants by structural elements occurred under optimal growing conditions such as in years with higher moisture availability and sowing on 5 October. Yield formation was significantly influenced by the weather conditions of the year, genotype and unaccounted factors. Sowing dates had a significant effect only on the manifestation of the plant height trait. There was a minor variation (3.8 %÷5.5 %) in plant height in all varieties and breeding lines. Different levels of variability were found for the following traits: number of productive stems varied from Cv=16.4 % (second sowing date in the dry 2019/20) to Cv=27.6 % (first sowing date in the favourable 2020/21); main head grain content and thousand grain weight – Cv=10.7÷17.6 % and Cv=8.8÷16.9 %, respectively. Regardless of varietal characteristics, the main spike length had insignificant (Сv=5.6÷8.8 %) phenotypic variability with a range of variation of 0.2–2.0 cm. There were determined the variability levels of traits by the spikelet number per spike (Сv=5.7 %÷8.6 %), by grain weight per spike (Сv=13.1÷20.5 %) and per plant (Сv=20.5÷36.3 %). Conclusions. The varieties MIP Assol, Hratsiia MYR, MIP Dniprianka, MIP Yuvileina and breeding lines LUT 55198, LUT 37519 consistently formed a high level of productivity elements regardless of sowing dates and conditions of the growing year, which indicates their high adaptive capacity. They are recommended for breeding programmes as valuable parental components. Key words: productivity parameters, trait, variation, sowing date, year conditions

Decline in tuber number and weight of potato (<i>Solanum tuberosum</i> L) associated with drought in 2020 and 2021 in a humid region of eastern Hokkaido

The objectives of this study were to verify changes in potato tuber number and weight under climatic variations in a cool region in Japan. We investigated potato growth over a 3-year period from 2019, establishing plots with different planting times and maturity types. In 2020, early planting encountered dryness during the tuber formation period after sprouting, which significantly reduced tuber numbers. Temperature was identified as the main factor contributing to the annual variation in potato yield, largely due to unusually high temperatures during the study period. In 2021, hot and dry conditions in early summer (mid to late July) corresponded to the tuber bulking period and reduced the yield owing to light tuber weight regardless of the planting time and variety. The present study provided insights into the variability of yield components in potato by focusing on drought effects, weather, and cultivation factors, which vary substantially.

Interaction between pesticides applied alone or in mixtures in corn

The objective of this work was to evaluate the selectivity of herbicides applied alone or in tank mix, and also of combinations of different classes of pesticides (fungicides, herbicides and insecticides) on corn. An experiment was installed in the 2017/18 crop to assess herbicide selectivity, and repeated in 2018/19. The second experiment aimed to assess the selectivity of mixtures of different classes of pesticides, and was installed only in 2017/18. The experimental design adopted in the tests was randomized blocks, with four replicates. In each trial, a total of 16 treatments were evaluated, plus a control. At 7, 14 and 21 days after the application of treatments the phytotoxicity to corn was evaluated and the yield components and grain yield were determined. Herbicides caused low levels of injury to the corn plants, with small variations in yield components, and affected crop yield differently. The mixtures of pesticides promoted low phytotoxicity, affected yield components inconsistently and caused changes in corn yield. Although these herbicides and other pesticides are registered for use in corn crops, application alone or in tank mix of certain molecules can cause losses in grain yield.

Comparing different propagation methods for giant reed (Arundo donax L.) across three years from planting

Limits in propagation are hampering the diffusion of giant reed cultivation for biomass. The objective of this study was to compare rhizomes and micropropagated plants with stem cuttings obtained in spring vs late winter (with and without side shoots, respectively) and immediately planted. A three-years field trial was carried out, assessing how rapidly giant reed establishes, and how its yield components (i.e. crop height, stem density, stem diameter) and its rhizomes develop over years depending on the propagation method adopted.Long-lasting variations in yield components depending on propagation were found. In the three years, biomass yield was steadily higher in rhizome-propagated stands (+64% than the average of the other propagation materials), while no significant interactions with the year of study were observed. Stems were thicker in rhizome-propagated and thinner in micropropagated plants, while cutting-propagated ones showed intermediate values. Micropropagation led to a significantly lower ratio between the biomass of rhizomes and the number of rhizome buds. Moreover, micropropagated plants were shorter (crop height: 34%), while stem density was nearly doubled: an inverse relationship between tillering and elongation was highlighted. Plants obtained from winter cuttings were taller than those obtained in spring, although the height difference was mostly achieved towards the end of the vegetative season. At initial growth stages, winter cuttings were slower than spring cuttings in increasing sprout density. Immediately-planted cuttings showed potential to replace micropropagated plants. In particular, cuttings obtained in spring, showed suitability for on-farm propagation, by means of collection from existing stands followed by direct planting.

Developing perennial fruit crop models in APSIM Next Generation using grapevine as an example

AbstractA new model for grapevines (Vitis vinifera) is the first perennial fruit crop model using the Agricultural Production System sIMulator (APSIM) Next Generation framework. Modules for phenology, light interception, carbohydrate allocation, yield formation and berry composition were adapted or added into APSIM Next Generation to represent the nature of fruit-bearing vines. The simulated grapevine phenological cycle starts with the dormancy phase triggered by a critical photoperiod in autumn, and then goes through the subsequent phenophases sequentially and finally returns to dormancy for a new cycle. The canopy microclimate module within APSIM Next Generation was extended to allow for row crop light interception. The carbohydrate arbitrator was enhanced to consider both sink strength and sink priority to reflect carbohydrate reserve as a concurrent competing sink. Weather conditions and source–sink ratio at critical developmental stages were used to determine potential grapevine yield components, e.g. bunch number, berry number and berry fresh weight. The model was calibrated and tested extensively using four detailed data sets. The model captured the variations in the timing of measured budburst, flowering and véraison over 15 seasons across New Zealand for five different varieties. The calculated seasonal dynamics of light interception by the row and alley were consistent with field observations. The model also reproduced the dynamics of dry matter and carbohydrate reserve of different organs, and the wide variation in yield components caused by seasonal weather conditions and pruning regimes. The modelling framework developed in this work can also be used for other perennial fruit crops.

Proximal sensing of vineyard soil and canopy vegetation for determining vineyard spatial variability in plant physiology and berry chemistry

Proximal sensing is used in vineyards to precisely monitor and manage spatial and temporal variability while reducing laborious and repetitive measurements. Soil electrical conductivity (EC) and canopy vegetation indexes are two frequently assessed variables with off-the-shelf sensors. In this study, the ecophysiological variability of a commercial vineyard comprising three varieties in three blocks, Cabernet-Sauvignon (CS), Cabernet franc (CF), and Petit Verdot (PV), was investigated. Random sampling was used to continuously assess spatial variability in plant physiology and berry composition. Soil EC and NDVI were also continuously monitored throughout the season. There was a noticeable spatial pattern in the normalised differential vegetation index (NDVI) in the vineyard and soil EC. The spatial pattern of NDVI can be partially elucidated by the season-long stem water potential (Ψstem), which was lowest in the CS block. However, leaf photosynthesis did not match this spatial pattern. The spatial distribution of NDVI and soil EC did not satisfactorily explain the spatial variations in yield components and berry chemistry. Principal component analyses (PCA) were performed resulting in a clear discrimination of each of the three cultivars. Soil EC showed a significant relationship with Ψstem integrals, total skin anthocyanins and tri- to di-hydroxylated flavonoids. In each cultivar block, soil EC showed some capability to be related to plant water status, and NDVI showed a relationship with yield. Overall, this study provided evidence of the spatial variability of grapevine physiology in a commercial vineyard with three cultivars. Also, it showed that the cultivar effect and uniform crop level management can diminish the efficiency of proximal sensing, thus weakening the relationship of soil and canopy indexes with plant physiology and berry chemistry. Nonetheless, our study showed that it is possible to apply temporal proximal sensing methods when assessing plant water status, primary metabolism, yield and berry secondary metabolism, which give an indication of the possibility of managing the spatial variability of both plant physiology and berry chemistry.

Physiological, Biochemical and Yield-Component Responses of Solanum tuberosum L. Group Phureja Genotypes to a Water Deficit.

Water deficits are the major constraint in some potato-growing areas of the world. The effect is most severe at the tuberization stage, resulting in lower yield. Therefore, an assessment of genetic and phenotypic variations resulting from water deficits in Colombia germplasm is required to accelerate breeding efforts. Phenotypic variations in response to a water deficit were studied in a collection of Solanum tuberosum Group Phureja. A progressive water deficit experiment on the tuberization stage was undertaken using 104 genotypes belonging to the Working Collection of the Potato Breeding Program at the Universidad Nacional de Colombia. The response to water deficit conditions was assessed with the relative chlorophyll content (CC), maximum quantum efficiency of PSII (Fv/Fm), relative water content (RWC), leaf sugar content, tuber number per plant (TN) and tuber fresh weight per plant (TW). Principal Component Analysis (PCA) and cluster analysis were used, and the Drought Tolerance Index (DTI) was calculated for the variables and genotypes. The soluble sugar contents increased significantly under the deficit conditions in the leaves, with a weak correlation with yield under both water treatments. The PCA results revealed that the physiological, biochemical and yield-component variables had broad variation, while the yield-component variables more powerfully distinguished between the tolerant and susceptible genotypes than the physiological and biochemical variables. The PCA and cluster analysis based on the DTI revealed different levels of water deficit tolerance for the 104 genotypes. These results provide a foundation for future research directed at understanding the molecular mechanisms underlying potato tolerance to water deficits.

Simulation of Fall Armyworm (Spodoptera frugiperda) Attacks and the Compensative Response of Quality Protein Maize (Zea mays, var. Mudishi-1 and Mudishi-3) in Southwestern DR Congo

In this paper, to assess the varietal ability to compensate defoliation damage caused by the fall armyworm, a trial was carried out at the INERA Mvuazi research center. The aim of this study was to determine the limit threshold of damage that could cause the significant loss of the harvest of the quality protein maize distributed in the Democratic Republic of the Congo. To do this, three factors including two varieties (Mudishi-1 and Mudishi-3) of quality protein maize, four rating damage and two growth stages were used into a factorial design with 3 replications. Simulation of damage caused by FAW consisted of cutting of blades for all visible leaves of plants. Damage rates simulating leaf destroying were 0%, 25%, 50%, 75% and 100%, occurring at two growth stages: stage V3 (2 to 4 weeks after emergence) and stage V7 (flowering stage). Results showed that damage factor combined with growth stage factor significantly influenced (p < 0.05) the yield component variables including yield losses, harvest rate, ear sizes, number of ears harvested and yield as well as the market quality of the ears, based on appearance quotation. Damage rate more than 50%, at all growth stages studied, caused grain losses upper than 50% regardless of variety. However, damage less than 50% at V3 stage resulted in grain losses under 10%. At the end of this study, we showed that the varieties of maize QPM (Mudishi-1 and Mudishi-3) would be able to compensate the damage caused by the FAW and achieve its yield, if the attacks damaging 25% of the leaves occur during V3.

Effectiveness of nitrogen and bio-fertilizer choice for improving growth and yield of hybrid rice (Oryza sativa L.) during dry season

Effect of nitrogen and bio-fertilizer on growth and productivity of hybrid rice (cv. PHB 71) was assessed during dry seasons of 2017 and 2018 at Research Farm of BCKV under new alluvial zone of West Bengal. The experiment was laid out in factorial randomized block design with 12 treatment combinations having 4 levels of N and 3 types of bio-fertilizer replicated thrice. Application at 180 kg N/ha produced tallest plants at 90 DAT with maximum LAI (60 DAT), DMA (90 DAT), tillers/hill (90 DAT) and CGR (30-60 &amp; 60-90 DAT). The same N rate resulted in highest panicles/m2, panicle length, panicle weight, filled grains/panicle and 1000-grain weight. A decrease in N dose from 180 to 150 kg/ha caused reduction in all those yield components; however, the variation was non-significant except for number of panicles/m2. Maximum grain yield, straw yield and harvest index was also achieved with 180 kg N/ha accounting 120.1, 34.9 and 32.8% more than the values obtained with zero-N; however, it was statistically at par with the yields and HI obtained with 150 kg N/ha. The Azospirillum application increased all the growth parameters, yield components and yield of hybrid rice over other tested bio-fertilizers (Azospirillum &gt; PSB &gt; K mobilizer), accounting 5.9 and 8.8% more than the yields obtained with PSB and K mobilizer. The interaction of N and bio-fertilizer exerted significant effect on growth attributes but failed to record any significant variations in yield components and yield of hybrid rice. The maximum economic benefit was achieved with combined application of 180 kg N/ha and Azospirillum.

Variation in yield components and bioactive contents of black cumin seeds (Nigella sativa L.) with application of animal manures in ultisol lowland of Bengkulu

Black cumin (Nigella sativa L) is known as herbal medicine that grows in subtropical regions and spreads from Asia to Europe. Plant parts that are used are seeds that contain bioactive compounds such as thymoquinone and thymol. Information about the growth and production from Indonesia is still limited. Therefore it is necessary to develop efforts to cultivate black cumin in Indonesia, especially in sub-optimal land as initial information in the field of plant adaptation studies. This study aimed to determine the effect of manure on yield components and bioactive content of black cumin in the ultisol lowland of Bengkulu. The study was conducted at Dehasen Bengkulu University research station at an altitude below 100 m above sea level. The accessions of India, Syria, and Kuwait were used at the main plot, whereas media for growing viz cow manure, chicken manure, and without manure as a subplot. The study was conducted in February 2019 using the Split Plot Design with three replications. Observations were made on the components of yields and bioactive levels of seeds. The results showed that the application of chicken manure increased the components of the yield of black cumin seed by parameter number of capsules per plant, number of seeds per capsule, and number of seeds per plant and tended to reduce the weight of 1000 seeds. An increasing level of thymoquinone in the cultivation of black cumin in ultisol lowland of Bengkulu was obtained in the cow manure application. The increased levels of seed thymoquinone were accompanied by decreased levels of thymol for all accession used.

Molecular Analysis and Adaptation Test of Code-qTSN4 and Code-qDTH8 Rice Lines

&lt;p&gt;Rice lines for increasing grain yield derived from Code variety that have loci associated to the spikelet number and early heading date (qTSN4 and qDTH8 locus, respectively) have been developed. The objectives of this research were to molecularly analyze, to evaluate the yield of Code-qTSN4 and Code-qDTH8 lines in the field, and to obtain the lines with yield potential of at least 10% higher than that shown by Code. The study was conducted in October 2016 to March 2017. The study was divided into two activities: molecular verification of the qTSN4, qDTH8, and Xa7 loci using specific markers and field trials at two locations in West Java, i.e. Sukamandi Experimental Station and Cianjur farmer’s paddy field. The genetic materials used were 56 rice genotypes consisted of 49 lines (Code-qTSN4 and Code-qDTH8) and 7 check varieties. Molecular analysis showed that all rice lines tested contained qTSN4, qDTH8, and Xa7 loci. All of the loci were in homozygous stage indicating that they were pure lines. Field trial results showed that Cianjur location gave much better on yield component variables than that in Sukamandi. The highest increase in spikelet number was shown by B6-4 planted at Cianjur with increase of 30.06% and B12-2 planted at Sukamandi with increase of 25.15% compared to Code. Both lines were classified as Code-qTSN4 line group. The qTSN4 and qDTH8 loci proved to increase yield more than 20% compared to Code. A total of 34 lines resulted from this study can be used for advanced yield trials conducted at several agro-ecologically different locations.&lt;/p&gt;

Assessment of genetic divergence in horsegram [Macrotyloma uniflorum (Lam) Verdc.] using quantitative traits

Genetic relatedness studies using 12 quantitative traits on 252 genotypes in horsegram revealed wide spectrum of variability for yield components. The genotypes were grouped into 25 clusters based on estimates of D2 statistic. Cluster I had the largest number with 83 genotypes followed by cluster II (77 genotypes), cluster IV (33 genotypes) and cluster III (30 genotypes). On the contrary, 20 solitary clusters from cluster V to XXV were formed except cluster XIV (9 genotypes) which could be given priority for specific trait improvement. Cluster XXI recorded the highest mean value for single plant yield (65.51 g). The intra and inter cluster distance was varying in magnitude indicating the presence of larger genetic diversity among accessions. The highest intra cluster distance was noticed in cluster XIV (23.63) followed by cluster IV (22.37). Maximum inter cluster distance was observed between solitary clusters viz., cluster XXI and XVII followed by cluster XXI and XV and cluster XXI and VII. These clusters would offer superior segregants when employed in hybridization programme.

Soybean Seed Yield Response to Plant Density by Yield Environment in North America

Core Ideas Soybean seed yield response to plant density is dependent on yield environment.Low yield environments required higher plant densities than high yield environments.Plant density mainly affected per‐plant seed number.No differences in plant survival were observed among yield environments. Inconsistent soybean [Glycine max (L.) Merr.] seed yield response to plant density has been previously reported. Moreover, recent economic and productive circumstances have caused interest in within‐field variation of the agronomic optimal plant density (AOPD) for soybean. Thus, the objectives of this study were to: (i) determine the AOPD by yield environments (YE) and (ii) study variations in yield components (seed number and weight) related to the changes in seed yield response to plant density for soybean in North America. During 2013 and 2014, a total of 78 yield‐to‐plant density responses were evaluated in different regions of the United States and Canada. A soybean database evaluating multiple seeding rates ranging from 170,000 to 670,000 seeds ha−1 was collected, including final number of plants, seed yield, and its components (seed number and weight). The data was classified in YEs: low (LYE, &lt;4 Mg ha−1), medium (MYE, 4–4.3 Mg ha−1), and high (HYE, &gt;4.3 Mg ha−1). The main outcomes were: (i) AOPD increased by 24% from HYE to LYE, (ii) per‐plant yield increased due to a decrease in plant density: HYE &gt; MYE &gt; LYE, and (iii) per‐plant yield was mainly driven by seed number across plant densities within a YE, but both yield components influenced per‐plant yield across YEs. This study presents the first attempt to investigate the seed yield‐to‐plant density relationship via the understanding of plant establishment and yield components and by exploring the influence of weather variables defining soybean YEs.