Seed Yield Components Research Articles

Modeling the seed yield of Ajowan (Trachyspermum ammi L.) using artificial neural network and multiple linear regression models

Ajowan is a medicinal plant with useful pharmaceutical compounds in its seeds. Seed yield improvement in ajowan through a better understanding of the relationship between seed yield and its components is one of the most important goals of any breeding program. In the present study, artificial neural network (ANN) along with multiple regression model (MLR) were applied to predict the seed yield of ajowan through seed yield components. According to the simple correlation analysis, four characters (number of secondary branches, shoot dry weight, number of umbellets in an inflorescence, and biological yield) were selected as input variables in both artificial neural network and multiple linear regressions models. The network with SigmoidAxon transfer function, Levenberg-Marquart learning algorithm, one hidden layer with four neurons, 1000 training epochs and with a root mean square error (RMSE) of 0.147, a mean absolute error (MAE) of 0.127 and a determination coefficient (R2) of 0.932 was selected as the final ANN model. The performance of ANN was better than MLR with a RMSE of 0.210 and a r2 of 0.792. Biological yield and shoot dry weight were the most important yield components traits that affect the seed yield of ajowan and assigned as selection criteria using both ANN and MLR models.

Genetic potential to improve seed and forage yield simultaneously in smooth bromegrass under water deficit conditions

This study was conducted to assess genetic potential of smooth bromegrass for water stress and to identify the association among different seed and forage production related traits. Thirty-six genotypes were clonally propagated and evaluated in the field under two moisture environments (normal irrigation and water stress) during 2013–2015. High variation was observed among genotypes for all of the measured traits. Water stress had negative effects on seed yield and its components and reduced genotypic variation of measured traits. On average, water stress reduced seed and forage yield by 38 and 14%, respectively. Genetic coefficient of variation for seed yield and its components was higher under stress, providing opportunities for a greater selection differential. The estimates of heritability were higher in normal condition than water stress condition for all of the evaluated traits, which is advantageous for successful selection. Moreover, the majority of seed yield components had higher heritability estimates than seed yield. The higher heritability estimates of some seed yield components, compared to SYP, suggests a potential for indirect selection. The results showed that selection for both forage and seed yield is possible simultaneously in normal irrigation as well as in water stress environment. Genotypes 7, 8, 26 and 27 had high forage yield, while genotypes 23 and 27 had high seed yield under both normal irrigation and water stress condition. Three genotypes ranked among the top three for both seed and forage yield and under both normal irrigation and water stress condition. They are promising parents for further use in developing improved cultivars by cross-breeding.

Identification and dissection of single seed weight QTLs by analysis of seed yield components in soybean.

Single seed weight (SSW), or seed size, is a seed yield components (SYC) in soybean, and it is suggested that the genetic factors regulating SSW are involved in the control of other SYCs. The quantitative trait loci (QTLs) for SSW and their effects on the other SYCs were investigated using a recombinant inbred line population derived from typical small- and large-seeded cultivars that were cultivated in two different environments. QTL analysis detected four environmentally stable QTLs for SSW, two of which coincided with the defined loci, qSw17-1 and Ln. The effects of the other loci, qSw12-1 and qSw13-1, were confirmed by analyzing residual heterozygous line progenies derived from the recombinant population. These four QTL regions were also involved in the control of an additional SYC, namely the large-seeded allele at each locus that reduced either the number of pods per plant or the number of ovules per pod. These results suggest the presence of at least two different regulatory mechanisms for SSW. Isolation of genes responsible for these QTLs provides an important tool in the understanding and utilization of SSW diversity for soybean breeding.

Variability in Seed Yield of Multi-Cut Barseem Clover (Trifolium alexandrinum, L.) Gene Pool

The objective of the recent study was to detect variability in Egyptian multi-cut barseem gene pool via studying fourdifferent commercial populations regarding seed yield and seed yield components. These were; Khadarwi, Meskawi,Serow and Helaly. Means of total seed weight.plant-1were approximately similar for Khadarawi (26.131g) and Meskawi(26.122) population. This was affected by similar figures for seed yield components. Serow population scored the leastseed weight.plant-1 (21.981g) affected largely by the least number of seed.head-1 (37.79 seed.head-1). Meanwhile, Helalypopulation had the second least total seed weight.plant-1 (23.49g) affected also by low figure of number of seed.head-1.Major proportion of total variance (σ2p)was contributed by the genotypic component (σ2g) in total seed weight. plant-1 andnumber of heads.plant-1in all studied barseem populations. Whereas, the genotypic variance represented a very limitedportion of phenotypic variance for other studied seed yield components in all studied populations. Heritability estimates inkhadarawi and Meskawi populations postulated a strong genetic control on total seed weight .plant-1 and number of heads.plant-1 (0.98 and 0.97%). While, weak estimates were recorded for number of seeds.head-1, seed weight.head-1and 1000seed weight (0.23, 0.13 and 0.04%, respectively). Estimates of expected gain from selection the top 10% of half-sibfamilies of khadarawi population might result in 59.85% increase in total seed weight, which amount to15.64 g.plant-1.Concerning Helaly population selecting the top 10% of half-sib families might result in total seed weight.plant-1 andnumber heads.plant-1 increase of 72.43 and 67.09% which might amount to 17.01g.plant-1 and 105.8heads.plant-1.

Identifying Transcription Factor Genes Associated with Yield Traits in Chickpea

Identification of potential transcription factor (TF) gene-derived natural SNP allelic variants regulating pod and seed yield component traits by large-scale mining and genotyping of SNPs in natural germplasm accessions coupled with high-resolution association mapping is vital for understanding the complex genetic architecture of quantitative yield traits in chickpea. In these perspectives, the current study employed a genome-wide GBS (genotyping-by-sequencing) and targeted gene amplicon resequencing-based simultaneous SNP discovery and genotyping assays, which discovered 1611 novel SNPs from 736 TF genes physically mapped on eight chromosomes and unanchored scaffolds of kabuli chickpea genome. These SNPs were structurally and functionally annotated in diverse synonymous and non-synonymous coding as well as non-coding regulatory and intronic sequence components of chickpea TF genes. A high-resolution genetic association analysis was performed by correlating the genotyping information of 1611 TF gene-based SNPs with multi-location/years field phenotyping data of six major pod and seed yield traits evaluated in a constituted association panel (326 desi and kabuli germplasm accessions) of chickpea. This essentially identified 27 TF gene-derived SNPs exhibiting significant association with six major yield traits, namely days to 50% flowering (DF), plant height (PH), branch number (BN), pod number (PN), seed number (SN) and seed weight (SW) in chickpea. These trait-associated SNPs individually and in combination explained 10–23% and 32% phenotypic variation respectively for the studied yield component traits. Interestingly, novel non-synonymous coding SNP allelic variants in five potential candidate TF genes encoding SBP (squamosal promoter binding protein), SNF2 (sucrose non-fermenting 2), GRAS [Gibberellic acid insensitive (GAI)-Repressor of GAI (RGA)-SCARECROW (SCR)], bZIP (basic leucine zipper) and LOB (lateral organ boundaries)-domain proteins associated strongly with DF, PH, BN, PN, SN and SW traits respectively were found most promising in chickpea. The functionally relevant molecular signatures (TFs and natural SNP alleles) delineated by us have potential to accelerate marker-assisted genetic enhancement by developing high pod and seed yielding cultivars of chickpea.

Keragaman dan Pengelompokan Sumber Daya Genetik Kacang Tunggak [Vigna unguiculata (L.) Walp.

Cowpea [Vigna unguiculata (L.) Walp.] is a legume that tolerant to drought and acid soil, that is prospective for development in sub-optimal area. A total of 150 cowpea accessions were grown at Muneng Research Station (Probolinggo) in dry seasson of 2014, using a randomized block design, with two replications. Each accession were planted along two rows of 4 m. The accession was varied for the qualitative and quantitative traits. Most of the accession had ovate leaf shape, flower color purple, cream color of mature pod, and seed color brown to yellowish. Seed yield had a high phenotipic and genotypic coefficient of variation and genetic advance. Low of phenotipic and genotypic coefficient of variation were shown on days to 50% flowering and days to physiological maturing. Characteristics of cowpea accessions for eight variables 64.2% can be explained by three factors. The first factor relates to seed yield component (number of fertile nodes, number of branches, and seed weight), second factor associated with plant age (date of flowering and harvesting), and the third factor is the supporting factors (plant height, pod length, and number of seeds per pod). Accessions of cowpea could be divided into three groups. Date of flowering and harvesting were a determinant variable discriminant function. Group I consisting 70 accessions dominated by accessions with early maturity, medium plant height, long pods, high number of seeds per pod and high seed yield. Group II consisting of 47 accessions with moderate maturity, short plants, short pods, low number of seeds per pod and low seed yield. Group III consisting of 33 accessions was characterized by moderate maturity, high plant, short pods, high number of seeds per pod and high seed yield.

The effect of water salinity on seed yield and seed yield components of miracle genotypes of Fennel (Foeniculum vulgare Mill.)

In order to study the effects of water salinity on fennel seed yield and seed yield components, an experiment was conducted at Agricultural and Natural Resource Research Center of Isfahan in a split plot experiment based on randomized complete block design with three replicates, during 2012- 2014. Four superior Foeniculum vulgare genotypes (Lorestan, Hamedan, P11- 820065 and 11486) in three treatments (control, 5 and 8 dS/m) were investigated. Number of inflorescences and umbels, seeds per umblets, seed yield, weight of 1000 seeds, plants height in 50% flowering and 100% flowering time, dry weight of plant aerial parts, plant dry weight/wet weight, days until 50% flowering and maturing time, percentage of essential oil and essential oil yield were evaluated. Results showed that the effect of salinity was significant on all traits with the exception of essential oil percentage. Effect of genotype wasn’t significant on seed per umblet and seed yield. Interactions of salinity and genotype were significant on all traits except for essential oil percentage. In control treatment P11- 820065 had the highest seed yield and essential oil yield (2359.8 and 91.5 kg/ha, respectively) but by increasing in salinity levels, seed yield of native genotypes was higher than P11- 820065 and Lorestan was the superior genotype with 1463 and 4/38 kg/ha, respectively. There was a positive correlation between seed yield with essential oil and forage yields. Based on the results, salinity stress decreased the seed, essential oil and herbage yield economically.

Effects of foliar application of yeast extract on seed yield, and seed yield components of five sorghum cultivars.

A field experiment was conducted at the experimental farm, College of Agriculture, Al-jadrea, Baghdad, Iraq during spring season of 2016 to study the effects of foliar application with yeast extract on grain yield, yield components of five sorghum cultivars. The layout of the experiments was split plot design with three replicates , The five cultivars it is kafeer, bohooth 70, rabih, inkath and local, occupied the main plots while yeast extract concentrations 0, 5, 10,15 gr L-1 occupied the sub-plots. Results of this experiment are summarized as follows: number of seeds per head, seed yield increased with the increase of yeast extract concentrations and the best concentration in most of yield characters was 15gm L-1. The cultivar buhooth 70 was superior in 1000 seed weight, seed yield while the cultivar Rabih was superior in number of seeds per head.

Discerning morpho-anatomical, physiological and molecular multiformity in cultivated and wild genotypes of lentil with reconciliation to salinity stress.

One hundred and sixty two genotypes of different Lens species were screened for salinity tolerance in hydroponics at 40, 80 and 120 mM sodium chloride (NaCl) for 30 d. The germination, seedling growth, biomass accumulation, seedling survivability, salinity scores, root and shoot anatomy, sodium ion (Na+), chloride ion (Cl-) and potassium ion (K+) concentrations, proline and antioxidant activities were measured to evaluate the performance of all the genotypes. The results were compared in respect of physiological (Na+, K+ and Cl-) and seed yield components obtained from field trials for salinity stress conducted during two years. Expression of salt tolerance in hydroponics was found to be reliable indicator for similarity in salt tolerance between genotypes and was evident in saline soil based comparisons. Impressive genotypic variation for salinity tolerance was observed among the genotypes screened under hydroponic and saline field conditions. Plant concentrations of Na+ and Cl- at 120 mM NaCl were found significantly correlated with germination, root and shoot length, fresh and dry weight of roots and shoots, seedling survivability, salinity scores and K+ under controlled conditions and ranked the genotypes along with their seed yield in the field. Root and shoot anatomy of tolerant line (PDL-1) and wild accession (ILWL-137) showed restricted uptake of Na+ and Cl- due to thick layer of their epidermis and endodermis as compared to sensitive cultigen (L-4076). All the genotypes were scanned using SSR markers for genetic diversity, which generated high polymorphism. On the basis of cluster analysis and population structure the contrasting genotypes were grouped into different classes. These markers may further be tested to explore their potential in marker-assisted selection.

The Impacts of Nano-Structured Nutrients on Chickpea Performance under Supplemental Irrigation

Chickpea is a legume of the family Fabaceae and the most widely grown crop in the semi‑arid Mediterranean regions. This pulse crop can grow on almost any soil and is well adapted to the semi‑arid conditions, but for good growth it requires a fertile soil with good residual moisture. Therefore, nutrient‑and water‑management practices are necessary agronomic options to improve chickpea production. The objective of this study was to evaluate the effect of different conventional and nano‑fertilizers on growth and yield of Kabuli chickpea under supplemental irrigation. The experiment was carried out at a research field in dry highland of Maragheh, North western Iran. Plants were grown under rainfed situation during the vegetative growth and supplement irrigations was applied during flowering and seed filling stages. The effect of nine nutrient treatments including T1: control (no fertilizer application), T2: nano‑chelated iron, T3: nano‑chelated manganese, T4: nano‑chelated copper, T5: nano‑chelated boron, T6: organic manganese, T7: conventional NPK fertilizer, T8: multi‑nutrient nano‑fertilizer and T9: nano‑chelated zinc were evaluated. Result showed that application of multi‑nutrient nano‑fertilizer, conventional NPK fertilizer and nano‑chelated Zn considerably improved the both vegetative growth (e.g. plant height, canopy width, number of the branches) and yield components. Also the highest chlorophyll concentration (P < 0.05) was recorded for plant grown by application of multi‑nutrient / compound fertilizers. There was a significant positive correlation between chlorophyll concentration and seed yield components (P < 0.01). Among the applied micronutrients, plants significantly responded to nano‑chelated Zn. Conventional NPK significantly improved the lateral growth (canopy width, ground cover, branches numbers).The results pointed out that the best performance of chickpea could be achievable through utilization of nano‑ of multi‑nutrient fertilizer, with the simultaneous release of micronutrients and macronutrients. The findings provided illustrative information in order to appreciate the importance of balanced crop nutrition in semi‑arid Mediterranean region.

Path and correlation analysis of perennial ryegrass (Lolium perenne L.) seed yield components

AbstractMaximum perennial ryegrass seed production potential is substantially greater than harvested yields with harvested yields representing only 20% of calculated potential. Similar to wheat, maize and other agriculturally important crops, seed yield is highly dependent on a number of interacting seed yield components. This research was performed to apply and describe path analysis of perennial ryegrass seed yield components in relation to harvested seed yields. Utilising extensive yield components which included subdividing reproductive inflorescences into five size categories, path analysis was undertaken assuming a unidirectional causal‐admissible relationship between seed yield components and harvested seed yield in six commercial seed production fields. Both spikelets per inflorescence and florets per spikelet had a significant (p < .05) direct effect on the overall seed yield; however, total path correlation coefficients showed that inflorescence size had the largest positive influence on seed yield via its indirect effects on other seed yield components. Our results will allow seed producers, seed production researchers and plant breeders alike to more efficiently increase harvested seed yield.

Physiological Role of Exogenous Nitric Oxide in Improving Performance, Yield and Some Biochemical Aspects of Sunflower Plant Under Zinc Stress

The present study was undertaken to examine the possible roles of sodium nitroprusside in protection against oxidative damage due to zinc toxicity in sunflower plants. Physiochemical parameters in sunflower plants exposed to Zn2+ (100, 200 and 300 mg/kg soil) alone or combined with SNP were measured. The results showed that excess of Zn decreased plant growth, seed yield components and photosynthetic pigments content. On the other hand, Zn stress increased the level of non-enzymatic antioxidants (ascorbic acid and reduced glutathione) and enzymatic antioxidants (superoxide dismutase, ascrobate peroxidase and glutathione reductase), coupled with the appearance of novel protein bands. Furthermore, Zn stress increased Zn content in roots and shoots. The amounts of Zn in roots were higher than shoots. A marked increase in total saturated fatty acids accompanied by a decrease in total unsaturated fatty acids was observed. Exogenously application of SNP (20 µM) increased growth parameters, photosynthetic pigments content, ascorbic acid and glutathione contents, antioxidant enzyme activities and the quality of the oil in favour of the increase of unsaturated fatty acids. Moreover, SNP application increased Zn concentration in roots and inhibited Zn accumulation in shoots. Therefore, it is concluded that SNP treatment can help reduce Zn toxicity in sunflower plants.

Genetic Analysis of Seed Yield Components and its Association with Forage Production in Wild and Cultivated Species of Sainfoin

Genetic Analysis of Seed Yield Components and its Association with Forage Production in Wild and Cultivated Species of Sainfoin

Genotype × Environmental Interaction on Seed Cotton Yield and Yield Components

Cotton yield and fibre quality parameters are dependent on the environment in which the crop is grown. A major challenge in crop genotype recommendations is genotype × environment interaction. The identification of cultivars with high adaptability and stability is one of the best ways to address this challenge. Genotype × Environmental interaction on Gosypium hirsutum was investigated. Ten genotypes were planted in a randomised complete block design with three replications. Collected data were subjected to Analysis of Variance (ANOVA) with genotype and location as factors. Additive Main Effect and Multiplicative Interaction model which combines standard analysis of variance with principal component analysis was used to investigate the genotype main effects, environment main effects and the GE interactions. Significant genotype × environment interactions existed for lint yield, boll weights, staple length, and fuzzy seed grade. There were no significant cultivar × site interactions on total seed cotton yield. Cotton cultivars respond differently to different growing conditions implying that, correct choice of varieties by growers for specific production conditions, must be a must to avoid losses due to genotype × environment interactions.

Seed Yield Components in Single Plants of Diverse Scandinavian Tetraploid Red Clover Populations (Trifolium pratense L.)

Satisfactory seed yield of red clover (Trifolium pratense L.) cultivars is crucial for the availability of seeds on the market. Many breeders and researchers have used seed yield components to measure, compare, and explain differences in seed yield between diploid and tetraploid red clover cultivars and populations; however, the relative importance of each component varies between studies. In 2011 and 2012, single‐plant trials with several tetraploid and one diploid red clover cultivar were established at the Norwegian plant breeding station at Bjørke. The goal was to study the impact of different seed‐yield components on the seed yield of tetraploid plants. Seed weight per flower head was the seed‐yield component that correlated best with the seed yield plant−1 (r = 0.91 and r = 0.68 in 2011 and 2012, respectively). Path coefficient analysis has also shown that the seed weight per flower head had the highest direct impact on seed yield plant−1 (direct path coefficients were 0.867 and 0.783 in 2011 and 2012, respectively). In comparison, the direct path coefficients for calculated number of flower heads, which was previously highlighted as the most important seed‐yield component, were lower and more variable (0.739 and 0.392 in 2011 and 2012, respectively). Since previously seed yield per flower head was also identified as the most important seed‐yield component in dense plant canopy, this component might have the potential to select for improved seed yield of new cultivars based on single plants. However, further studies are required to confirm this conclusion.

Influence of year and row spacing on yield component andseed yield in Alfalfa (Medicago sativa L.)

A 5 year field experiment was conducted to investigate the influence of different yearly climatic features and row spacing on seed yield and seed yield components during the 2008-2012 growing seasons in semi-arid soils in northwest China. Rows pacing treatments were 30, 60, 90, and 120 cm. Seed yield and some seed yield components were determined for all treatments. The year affected seed yield components markedly, but row spacing except for the quantity of seeds per pod. The interaction of year and row spacing have a significant impact on racemes per square meter and seed yield (P less than 0.05). The highest seed yield was gained in the fifth year (409.83 kg ha-1) with 60 cm row spacing (456.30kg ha-1). These results indicated that alfalfa should be planted with 60cm row spacing, which was most productive for improving the alfalfa seed yield in semi-arid lands.

Unravelling the inheritance, QST and reproductive phenology attributes of the tetraploid tropical grass Brachiaria ruziziensis (Germain et Evrard)

AbstractThe autotetraploid forage Congo signal grass (Brachiaria ruziziensis) is an important component in the Brachiaria breeding programme. As with other tropical forage grass species, the association between flowering and seed yield components, the mode of inheritance and the effects of population structure on phenotypic breeding are lacking. Seventeen characteristics evaluated in 59 half‐sib progeny of seven subpopulations were analysed using a mixed model methodology. According to the commonality analysis, the total seed yield (0.67) and number of days to flowering (0.22) had a greater influence on the filled‐seed yield. The flowering synchrony, total number of panicles, filled‐seed yield, green matter yield and dry matter yield presented statistically significant additive genetic variance between and within the subpopulations. The QST estimates ranged from 0.09 for the flowering synchrony index to 0.31 for the filled‐seed yield. The effects of population structure and its use in breeding programmes are further discussed.

High‐Input Management Systems Effect on Soybean Seed Yield, Yield Components, and Economic Break‐Even Probabilities

Elevated soybean [Glycine max (L.) Merr.] prices have spurred interest in maximizing soybean seed yield and has led growers to increase the number of inputs in their production systems. However, little information exists about the effects of high‐input management on soybean yield and profitability. The purpose of this study was to investigate the effects of individual inputs, as well as combinations of inputs marketed to protect or increase soybean seed yield, yield components, and economic break‐even probabilities. Studies were established in nine states and three soybean growing regions (North, Central, and South) between 2012 and 2014. In each site‐year both individual inputs and combination high‐input (SOYA) management systems were tested. When averaged between 2012 and 2014, regional results showed no seed yield responses in the South region, but multiple inputs affected seed yield in the North region. In general, the combination SOYA inputs resulted in the greatest yield increases (up to 12%) compared to standard management, but Bayesian economic analysis indicated SOYA had low break‐even probabilities. Foliar insecticide had the greatest break‐even probabilities across all environments, although insect pressure was generally low across all site‐years. Soybean producers in North region are likely to realize a greater response from increased inputs, but producers across all regions should carefully evaluate adding inputs to their soybean management systems and ensure that they continue to follow the principles of integrated pest management.

Seed Yield of Norwegian and Swedish Tetraploid Red Clover (Trifolium pratense L.) Populations

While tetraploid plants of red clover are taller, have thicker stems, and have broader leaves that altogether result in a higher forage yield compared to diploids, they generally have substantially lower seed yields than diploid plants. Tetraploid red clover can be induced chemically by colchicine or nitrous oxide (N2O) and sexually by union of unreduced gametes. The average seed yield of tetraploid red clover in Norway is 60% of the diploid yield, while in Sweden it is 75%. One objective of this paper was to examine whether there is a difference in seed yield among chromosome doubled tetraploids and crossed tetraploids. A second objective was to investigate differences in seed yield and seed yield components in Norwegian and Swedish tetraploid populations. The third objective was to study which yield component most correlates with the seed yield per hectare. Seed production experiments were established at Landvik and Bjørke in Norway and Svalöv and Lännäs in Sweden. Populations made by crossings of tetraploids gave significantly greater yield (p < 0.001) compared to populations that were made by chromosome doubling. On average, Norwegian and Swedish varieties had equal yields in both experimental years. Norwegian and Swedish varieties differed mostly in earliness traits. Swedish populations began flowering on average 4 d earlier than Norwegian populations. Genotypic correlations showed that seed yield per flower head was the component with the highest correlation (r = 0.956 and r = 0.977) with yield per hectare in both experimental fields. Results from the second experimental year indicate a trend towards improved seed yield after several cycles of recurrent selection for higher seed yield per flower head.

Physiological traits related to drought tolerance in Brassica

Physiological basis of genetic variability in drought response and its association with yield and related indices is not clear in Brassica. In this study 36 accessions belonged to seven species of Brassica were evaluated under normal, moderate and severe stress environments. Physiological traits along with seed yield, seed yield components, oil content and two selection indices (stress tolerance index, STI and drought susceptibility index, DSI) were studied. Moderate and intense stress caused reduction in seed yield and the most studied traits. Based on the STI, B. carinata and B. juncea were identified as the superior species in moderate stress condition while B. oleracea was the most tolerant under intense stress. Moderate drought stress significantly increased the ratio of chlorophyll a to chlorophyll b (Chla/Chlb) while severe stress decreased it. Although relative water content (RWC) had positive correlation with STI, its heritability was low. Chlorophyll content (TChl) was associated with STI and had moderate heritability. Positive correlation was found between proline content and DSI under both stress conditions. Results showed large variation is among studied species for drought tolerance and related traits indicating that selection in this germplasm would be useful. Changes in chlorophyll content can be recognized as a key component affecting drought tolerance in Brassica.