Percentage Of Pod Set Research Articles

Effect of Synthetic Cytokinin Application on Pod Setting of Individual Florets within Raceme in Soybean

The application of synthetic cytokinin (6-benzylaminopurine, BA) to racemes of soybean genotype IX93-100 at 7 days after anthesis (DAA) enhanced pod-set percentage of the florets at the 5th position and above (numbered from the base on rachis). The endogenous cytokinin (trans-zeatin riboside) content of individual florets was measured at the 1, 3, 5, 7th position every 3 days after anthesis. Cytokinin was detected only from the florets at 9 DAA, and the content was higher in the more proximal florets while it became negligible in the 7th floret. These results suggest that an increase in the amount of cytokinin in individual florets might enhance the pod setting of the florets positioned at the middle or distal part within the raceme.

Ethylene perception inhibitor 1-MCP decreases oxidative damage of leaves through enhanced antioxidant defense mechanisms in soybean plants grown under high temperature stress

Ethylene is a stress hormone involved in early senescence and abscission of vegetative and reproductive organs under stress conditions. Ethylene perception inhibitors can minimize the impact of ethylene-mediated stress. The effects of high temperature (HT) stress during flowering on ethylene production rate in leaf, flower and pod and the effects of ethylene inhibitor on ethylene production rate, oxidative damage and physiology of soybean are not understood. We hypothesize that HT stress induces ethylene production, which causes premature leaf senescence and flower and pod abscission, and that application of the ethylene perception inhibitor 1-Methyl cyclopropene (1-MCP) can minimize HT stress induced ethylene response in soybean. The objectives of this study were to (1) determine whether ethylene is produced in HT stress; (2) quantify the effects of HT stress and 1-MCP application on oxidative injury; and (3) evaluate the efficacy of 1-MCP at minimizing HT-stress-induced leaf senescence and flower abscission. Soybean plants were exposed to HT (38/28°C) or optimum temperature (OT; 28/18°C) for 14d at flowering stage (R2). Plants at each temperature were treated with 1-MCP (1μgL−1) gas for 5h or left untreated (control). High temperature stress increased rate of ethylene production in leaves, flowers and pods, production of reactive oxygen species (ROS), membrane damage, and total soluble carbohydrate content in leaves and decreased photosynthetic rate, sucrose content, Fv/Fm ratio and antioxidant enzyme activities compared with OT. Foliar spray of 1-MCP decreased rate of ethylene production and ROS and leaf senescence traits but enhanced antioxidant enzyme activities (e.g. superoxide dismutase and catalase). In conclusion, HT stress increased ethylene production rates, caused oxidative damage, decreased antioxidant enzyme activity, caused premature leaf senescence, increased flower abscission and decreased pod set percentage. Application of 1-MCP lowered ethylene and ROS production, enhanced antioxidant enzyme activity, increased membrane stability, delayed leaf senescence, decreased flower abscission and increased pod set percentage. The beneficial effects of 1-MCP were greater under HT stress compared to OT in terms of decreased ethylene production, decreased ROS production, increased antioxidant protection, decreased flower abscission and increased pod set percentage.

Selective flower visitation behavior by pollinators in a radish F1 seed production field

For F1 seed production in Brassicaceae crops, cross-pollination between the two parental lines is vital and is dependent on the visitation behavior of insect pollinators. In a radish F1 seed production field using cytoplasmic male sterility system, visitation behaviors of different pollinator species and seed productivity of the recipient line were investigated in three stages during the flowering. As a result, honey bees (Apis mellifera and A. cerana) selectively visited either of two lines, while syrphid flies (various flies belonging to Syrphidae) tended to visit both lines. Despite the few observations of pollinator movements between the two lines, all flowers had received cross-pollen grains a few days after flowering. But in the late stage of flowering, increased cross-pollination by syrphid flies appeared to lead to an increase in the amount of cross-pollen grains deposited on the stigmas. The percentage of pod set and the number of seeds per pod varied among the three stages of the flowering. These variations might be caused by shifts in the amount of cross-pollen grains deposited on the stigmas due to the pollinators’ selective visitation behaviors. The selective visitation behavior of insect pollinators could potentially result in unstable F1 seed production through the insufficient cross-pollination.

Impact of bee pollinators on seed set and yield of Vicia villosa spp. dasycarpa (Leguminosae) grown under semiarid conditions

A field experiment was conducted during 2005/2006 at Jordan University of Science and Technology campus (32°30” N, 35°59” E), Irbid, Jordan, to study the role of bee visitors on seed set and production of Vicia villosa spp. dasycarpa grown under semiarid conditions. Two treatments were imposed on Vicia villosa plants before flowering: 1) Plants were covered in cages (control) or 2) Plants were left uncovered to permit bee visiting. The results of this experiment showed that V. villosa flowers were very attractive to worker honeybees as well as to few numbers of wild bees. The most frequent visitor species were A. mellifera and Anthophora albigena of family Apidae. V. villosa flowers attracted most of the bee visitors in the early hours of the day. The duration of their visit on the flowers also peaked early in the day and decreased toward the end of the day. The percentage of pod set of the un-covered plants averaged 14% out of the total florets on the plants, which was significantly higher than the covered plants (2%). These results indicated that the percentage of flower abscission was high and averaged more than 86%. Plant covering significantly reduced seed yield by reducing seed and pod number per plant and seed number per pod, but had no effect on individual seed weight. In conclusion, preventing bees from visiting during flowering of V. villosa spp. dasycarpa decreased seed set, seed yield and yield components. Further studies are needed to understand the high flower abscission and failure of seed set in this species.

Pollen Pistil Interaction in Inter-Specific Crosses of Vigna sp.

Inter-specific hybridization is mainly used to introgress pest and disease resistant genes. Vigna radiata and Vigna mungo are widely cultivated and consumed in India. These crops are highly affected by Mungbean Yellow Mosaic Virus (MYMV) disease and bruchid (Callasobruchus spp.) pest, leading to heavy yield loss. Vigna umbellata, a divergent Vigna species is found to be resistant to both MYMV and bruchids. Utilization of this species to introgress the resistance gene is marginal because of their inherent low crossability with the cultivated Vigna species. In the present study, V. umbellata was used as pollen donors in hybridization with V. radiata and V. mungo. Low percentage of pod set observed in the cross V. radiata×V. umbellata (12.89%) and V. mungo×V. umbellata (5.56%) indicated the presence of reproductive barriers that render introgression difficult. Aim of this study was to observe pre-fertilization barriers operating in V. radiata×V. umbellata and V. mungo×V. umbellata crosses. In vivo pollen germination and growth of pollen tubes were studied in inter-specific crosses using fluorescence microscope. The pollen grain germination on stigmatic surface was normal. A very common pre-fertilization barrier of slow rate of pollen growth, in addition to structural abnormalities in stigmatic and stylar regions was observed in both the crosses. However, the level of incompatibility was high in V. mungo×V. umbellata cross than V. radiata×V. umbellata. Measures to overcome incompatibility barriers before fertilization in these crosses to produce inter-specific hybrids are discussed.

Roles of Auxin and Cytokinin in Soybean Pod Setting

Soybean plants differentiate abundant floral buds, but most of them fail to grow pods and abort during development. Many studies indicated promotive effects of exogenously applied cytokinin on pod setting, but the effects of auxin application on pod set are ambiguous. In this study, we examined the changes in the concentrations of endogenous auxin and cytokinin in racemes and the effects of application of the two hormones on pod setting to clarify the role of auxin and cytokinin in soybean pod setting. The long-raceme soybean genotype IX93-100 was grown in pots and in the field. The auxin (IAA, indoleacetic acid) concentration in racemes was high for a long period from pre-anthesis to 9 days after anthesis (DAA) of the first flower on a raceme, but the cytokinin concentration was high for a short period, with a peak at 9 DAA. The IAA concentration was higher in distal portions of racemes, but the cytokinin concentration was higher in basal portions of racemes. In pot-grown plants, IAA applied to racemes tended to reduce the number of flowers and pods. In contrast, 6-benzylaminopurine (BA) applied to racemes before anthesis tended to reduce the number of flowers and pods, and that applied around 7 DAA significantly increased the pod-set percentage. However, these effects of IAA and BA application were slight in field-grown plants. These results indicate that the concentration of endogenous auxin and cytokinin in racemes changes in a different manner, and that cytokinins have a positive, and auxin a negative effect on pod setting when respective hormones are applied to racemes after the anthesis stage.

Effects of Source/Sink Ratio and Cytokinin Application on Pod Set in Soybean

A large proportion of soybean flowers abort during development. Pod set is significantly affected by the availability of assimilate and cytokinin in the flowers, but their synergistic effects on pod set remain unclear. The objective of this study was to examine whether pod set at specific nodes of a plant is enhanced by increasing the source-sink ratio and applying cytokinin to the nodes. The source-sink ratio was manipulated by removing floral buds excluding the specific nodes. As the ratio increased, the number of pods per node of control plants increased curvilinearly, reaching a plateau at high source/sink ratios. By contrast, in the cytokinin-applied plants, the number of pods per node increased without the plateau with increasing source/sink ratio, either by increasing the number of flowers or by increasing the pod-set percentage depending on the year. The results indicated that cytokinin plays a promotive role in increasing pod number in the plants with high levels of assimilate availability.

Root signal controls pod growth in drought-stressed soybean during the critical, abortion-sensitive phase of pod development

Abstract Root-originated chemical signals have been shown to regulate the response of vegetative shoot to drought in soybeans ( Glycine max L. Merr.). However, their roles in the growth of soybean reproductive structures under drought stress have not yet been investigated. To explore this, a glasshouse experiment was conducted in which potted soybeans were either well-watered (WW) or subjected to six levels of drought stress. Irrigation was withheld in pots at six different dates before anthesis to induce drought of different severity (D1–D6) at sampling, viz. 4 days after anthesis (DAA). Root water potential, leaf water potential, pod water potential, xylem sap [ABA], pod fresh weight (FW), and pod set percentage were determined. Soil water status in the pot was expressed as the fraction of transpirable soil water (FTSW). Pod FW started to decrease at FTSW=0.43±0.02, when pod water potential was similar to that in the WW plants, while root water potential had decreased to −0.15 MPa and xylem sap [ABA] had increased 9-fold as compared with the WW plants. Pod set started to decrease at FTSW=0.30±0.01, and coincided with the decrease in pod water potential. Pod set started to decrease only when pod FW had decreased ca. 30%. Based on the results, a potential role of drought-induced increase in xylem sap ABA in affecting pod growth was suggested. We proposed that a low pod water potential, which might have led to disruptions in metabolic activities in the pods, is important in determining pod abortion.

Loss of pod set caused by drought stress is associated with water status and ABA content of reproductive structures in soybean

Drought stress occurring during flowering and early pod expansion decreases pod set in soybean (Glycine max L. Merr.). The failure of pod set may be associated with changes in water status and ABA content in soybean reproductive structures under drought stress. To test this, pot experiments in an environmentally-controlled greenhouse were conducted, in which soybeans were exposed to drought stress around anthesis. In a preliminary experiment (Expt. I), irrigation was withheld at -6 (D1), -4 (D2) and -2 (D3) to 11 days after anthesis (DAA), then the droughted plants were re-watered to control levels until physiological maturity. Pod set percentage, seed yield and yield components were recorded. In the main experiment (Expt. II), irrigation was withheld from -11 to 10DAA. During the drying cycle, parts of the droughted plants were re-watered at 0, 3, 5, 7 and 10 DAA and kept well-watered until physiological maturity. In Expt. II, water status, ABA contents in xylem sap, leaves, flowers and pods were measured at 0, 3, 5, 7 and 10 DAA. The water potential in the flowers and pods was always lower than the leaf water potential. Turgor was decreased in leaves by drought 3 DAA, but remained at control levels in flowers and pods. Compared with well-watered plants, in severely droughted plants (10 DAA), xylem [ABA] increased about 60-fold; leaf [ABA] increased 9-fold; pod [ABA] increased 6-fold. During soil drying, flower and pod [ABA] was linearly correlated with xylem [ABA] and leaf [ABA], indicating that root-originated ABA and/or leaf ABA were the likely sources of ABA accumulated in the flowers and pods. In Expt. I, pod set and seed number per pod was unaffected by drought stress, while seed yield and individual seed weight was significantly decreased by drought. In Expt. II, significant reductions in pod set and seed yield were observed when re-watering the droughted plants at 3-5 DAA, re-watering the droughted plants later than this stage resulted in a similar pod set. Collectively, these results suggest that drought-induced decrease in water potential and increase in ABA content in flowers and pods at critical developmental stage (3-5 DAA) contribute to pod abortion in soybean.

The Effects of Figaron and Water Deficit on Seed Yield of Two Soybean Cultivars

In tropical and subtropical regions, soybean (Glycine max L.) often encounters a temporary water deficit in summer. Application of auxin during the reproductive period, when a water deficit and high temperature cause pod abscission, is expected to decrease pod abscission and thus increase seed yield. The present study was conducted in a greenhouse to assess the effects of Figaron (synthetic auxin) under various conditions of water deficiency in two soybean cultivars, Fukushirome and Miyagishirome. The plants were supplied with 500–, 300–, 200–, or 100–mL water per pot (5 L) three times a day. Figaron (lOOmgL–1) was sprayed 10 days after opening of the first flower. The rate of photosynthesis and transpiration were greatly decreased by water deficit in both cultivars. Application of Figaron slightly increased the rates of photosynthesis and transpiration irrespective of the water condition, though it temporarily decreased the rates during the initial few days after Figaron application. Figaron decreased the abscission of reproductive organs and increased the percentage of pod set, irrespective of the water condition, resulting in increase of seed yield. However, seed yield was severely decreased by water deficit, and application of Figaron could not fully overcome the decrease of yield caused by a severe water deficit.

アズキ品種・系統「エリモショウズ」と「十育134号」の開花数、着莢率および結莢率

アズキ品種・系統「エリモショウズ」と「十育134号」の開花数、着莢率および結莢率

Production of interspecific hybrids between Glycine max and G. tomentella through embryo culture

Interspecific hybrids have been obtained in an incompatible cross between Glycine max and G. tomentella through the in vitro culture of hybrid embryos. The percentage of successful pod setting in the crosses averaged 12.8% but there were marked differences depending on the soybean cultivar used as the female parent. Hybrid embryos at globular to heart stages were extracted from the embryo sac 15–25 days after pollination and cultured in vitro. Hybrid plants were successfully obtained by culturing the embryos on B5 medium supplemented with 0.1 mg/l IBA followed by culture on B5 medium supplemented with 0.1 mg/l TBA plus 0.25 mg/l 2-iP. The F1 plants resembled the wild male parent in growth form, but had an intermediate leaf shape between that of the parents.

Male sterility in birdsfoot trefoil (Lotus corniculatus L.)

This paper describes six male steriles in birdsfoot trefoil. Data on the following characters were recorded on these plants and on two male fertile plants: chromosome number, presence of pollen at tripping, percentage of irregularly shaped anthers, percentage of anthers with acetocarmine stainable pollen inside, maximum range of percentage of pollen fertility among anthers within a flower presenting pollen, and percentage of pod setting with selfing. All male steriles showed a somatic chromosome number typical of the species. All were indehiscent and complete control of pollination occurred in all but one. They differed in percentage of irregular anthers, percentage of anthers with stainable pollen inside, and range of percentage of pollen fertility among anthers within a flower. Indehiscence in flowers having some pollen inside the anthers was probably due to lack of internal pressure. It is concluded that these genotypes can be of value in breeding birdsfoot trefoil.

Effects of Cultivar and Flower Removal Treatments on the Temporal Distribution of Reproductive Structures in Bean1

Patterns of flower and pod production vary in time and in space among different cultivars and in response to environmental variables. A quantitative description of these variables will be important in studies in both stress‐management and cultivar development. Three experiments were conducted to determine the temporal distribution of flowering and the effects of flower removal on flower production and seed yield in dry bean (Phaseolus vulgaris L.). All experiments were planted at Davis, CA, on beds having 76‐cm centers. Experiments were conducted in different years, each experiment being a randomized complete block, having a minimum of four replications. In the cultivar comparison experiments, flowers of ‘Sacramento’, ‘Red Kidney’, ‘Sutter Pink’, and ‘T‐39’ were tagged over a 20‐day period beginning at first flower. By Day 12 or 13, all cultivars had reached peak flower production and had set pods, which would eventually constitute approximately 80% of their total seed yield. The rate of flower production differed among cultivars, but the earliest produced flowers had the highest pod set percentage. In the defloration experiment, flowers of Red Kidney and ‘California Red’ were removed or counted during various 10‐day intervals or combinations thereof over a 30‐day period. Removal of flowers during the first 20 days resulted in a significant increase in flower production during the last 10 days. Flower removal during Days 11 to 20 had the greatest impact on seed yield. In the partial defloration experiment whera e fixed proportion of flowers (e.g., every fourth flower) were removed over the entire season; flower production or yield was not significantly affected. A minimum of 20 days of flowering and pod set is essential for high yields. Stresses causing flower loss or pod abortion during Days 11 to 20 will have a significant impact on yield.

Hybrid embryo formation in an intersubgeneric cross of soybean (Glycin max MERILL) with a wild relative (G. tomentella HAYATA).

Percentage of successful pod setting in the intersubgeneric hybridization between G.max(2n=40, maternal) and G.tomentella(2n=80, paternal) was estimated to be 2.5 to 7.6% Germinability of the G.tomentella pollens of G.max stigmas, elongation of the pollen tube in the style and arrival of the pollen-tube tips at the ovules were detected by SEM and fluorescence microscopy. Aneuploidy (2n=64) of the hybrid embryo cells and peroxidase zymogram pattern specific to the hybrid-derived calli were observed by light microscopy (smear method) and polyacrylamide gel electrophoresis, respectivly. Moreover, histlogecal observation of the hybrid embryo was carried out to investigate the extant of the hybrid embryo growth. It was concluded that morphologically normal growth may continue at least until heart or a more advanced developmental stage, but markedly retarded growth accompanies it and eventually it ceases growing and death of the hybrid embryo results. Though, we couldn't get intact hybrid plant, all of the facts revealed proved formation of the genuine hybyid embryos between G.max and G.tomentella.

Bloom and Pod Set in Determinate and Indeterminate Soybeans Grown in China1

AbstractPrecise description of soybean [Glycine max (L.) Merr.] blooming and pod set characteristics are necessary for proper utilization of these characteristics in crop improvement. Seven determinate and five indeterminate soybean land cultivars from the lower Yangtze and Hwai Valleys (31° to 35°N 115° to 122°E) were examined in Nanjing, China (32°N 118°48'E) to describe the blooming habit and estimate the percentages of bloom and pod set. The plants had main raceme and subraceme (including subbranch) subdivisions on the floral nodes at the top, and primary branch and secondary branch subdivisions on the branch nodes at the bottom. In both determinate and indeterminate cultivars, the most important sectors in producing flowers and pods were the main raceme and the primary branch subdivisions. With a similar maturity, the determinate type had fewer main racemes, more subracemes, more primary and secondary branches, and more flowers per main raceme at a corresponding node than did the indeterminate type. The peak blooming period of a plant was from the 4th to the 14th day after first flowering. For the two stem‐termination types, on each subdivision, the flowering order was basically from the lower flowers to the upper ones, with the subraceme beginning to flower about the time that the main raceme at the same node finished blooming. For both stem‐termination types, the percentage of pod set was negatively correlated with maturity date and number of flowers. The percentage of pod set was relatively high on the terminal raceme for the determinate type. Percentage pod set of subracemes tended to decrease from the lower nodes to the upper ones for both types, but, at corresponding nodes, the percentage pod set of the determinate type was higher than that of the indeterminate type.

Nectar Production and Flower Visitors of Asclepias verticillata

Asclepias verticillata is self-incompatible and can propagate vegetatively. Nectar is produced mainly between 1800 and 2200 hr, throughout the 4-5 day life of the flower. Insect visitations at this time were infrequent on all four study sites, a seemingly anomalous situation ; most pollinia vectors visited the flowers during the day. The most frequent vectors were Hymenoptera, especially wasps and honeybees, and Lepidoptera, especially moths and the introduced cabbage white butterfly. Most flower-visiting insects were nectar thieves, carrying no pollinia. None of the potential pollinators seem to be closely coevolved, morphologically or seasonally, with the flowering of A. verticillata. The probability of an individual flower being visited by a potential vector is very low, corresponding to the observed low percentage of pod set, but between-site differences in composition of the vector fauna (proportional similarities less than 36%) and rates of visitation were not correlated with differences in levels of fruit production. Our earlier studies of the floral display and fruit production of Asclepias (Willson and Rathcke, 1974; Willson and Price, 1977) showed that fruit set varied considerably within and between conspecific populations. Furthermore, casual observations indicated marked spatial variation in insect visitors to A. verticillata. Roadside populations could often be spotted at a distance by the clouds of pierid butterflies clustered over the flowers, whereas flowers in other areas were seldom visited by pierids. These observations suggested that different populations of A. verticillata might encounter such different pollinator faunas that differences in timing and success of fruit production might result. We examined both temporal and spatial variation of the insect visitors and potential pollinators of A. verticillata and monitored temporal patterns of nectar production. Specifically, we here address the following questions: (1) Which insect visitors carry pollinia and are potential pollinators, and which visit the flowers for nectar but do not carry pollinia, and hence function as thieves? (2) Does the rate of visitation, the composition of the fauna of potential pollinators, and the proportion of visits made by thieves vary between sites or seasonally? Can these factors be related to fruit production? (3) Can the temporal pattern of nectar production be related to daily patterns of flower visits by potential pollinators?

Genetic basis of seed setting in alfalfa

The genetic basis of seed setting was evaluated in seven clones of alfalfa selected under predominantly self-pollinating conditions. They were hand crossed in all possible combinations. Their compatibility was studied by the percentage of flowers forming pods and number of seeds per pod during crossing. The variances for GCA, SCA and reciprocal effects were significant for percentage of pod set with a narrow sense héritability of 64 %. This suggested maternal influence of clones on percent pod set, controlled primarily by additive genetic components. GCA was the only significant component for number of seeds per pod with a narrow sense heritability of 71%. There were wide differences between the clones in their relative magnitude of GCA, SCA and reciprocal effects for both traits used as compatibility indexes. Performance of the diallel crosses was judged by studying seed yield and its related characters, namely seeds per pod, dry matter per plant, frost resistance, plant vigor and plant height. Although GCA and SCA variances were significant for all characters, reciprocal differences in general were absent. The SCA values were very high as compared to GCA. Narrow sense heritability values were very low while broad sense heritability were much higher. This suggested that almost none of the variation was due to additive genetic components and all the variability is controlled by interactions of a digenic, trigenic and quadrigenic nature and heterzozygosity. Heterosis was evaluated by comparing the seed yield of single crosses with their mid-parent and high-parent, and very high values were observed. Thus selection of better genes may not be feasible and further improvement in selected clones may have to be brought about by utilization of various interactions and heterosis. An attempt was made to find combinations of characters that may be used for the selection of seed yield but none were found to be satisfactory.

Ovule and embryo culture of the seeds obtained from the crosses between Hibiscus asper, H. cannabinus and H. sabdarlffa

(1) Crosses were made between Hibiscus asper, H. cannabinus and H. sabdarlffa ill order to obtain interspecific hybridizations through the ovule and embryo cultures. (2) The crossability differed according to the species used and the direction of cross. combination. The pods obtained from H. aspel-XH. cannabinus and H. asperXH. sabda, -zffa contained only immature seeds. In the reciprocal crosses between H. cannabinus and H. sabdarlffa, it was not possible to obtain seeds because of somatoplastic sterility. But the pods of H. sabdal-Iffa XH. cannabinus were set on the female plants for a longer time than those of the reciprocal crosses. When H. cannabinus was pollinated with H. sabdarlffa the ovule of the former were obtained after 4 days by treatment with lanolin containing 100 ppm IAA. The pods of H. sabdarzffa XH. asper were set on the female plants for 9, days or more after pollination, but they gradually fell off. The pods of H. cannabinusX H. asper fell off shortly after pollination. (3) Even though the plants developed a disease, H. sabdal-Iffa could be used as a female plant, and showed a higher percentage of pod setting than did the healthy plants.

GENETIC NATURE OF TWO INDEXES OF COMPATIBILITY IN ALFALFA

Seven clones selected for their high seed and forage yielding ability were crossed in a diallel manner to obtain the estimates of GCA, SCA and reciprocal effects of the parental clones in various hybrid combinations. The analysis of the diallel crosses revealed that the variances for GCA, SCA and reciprocal effects were significant (0.01 level) for percentage of pod set during the crossing program. Number of seeds per pod set were significant for the general combining ability. The general combining ability appeared to be of greater importance for both the characters studied, and the additive genetic variance seems to constitute approximately 63% of the total variance for percentage of pod set and 71% of the total variance for number of seeds per pod set. However, wide differences were found among the clones in the relative magnitude of GCA, SCA and reciprocal effects for both traits.