Selection of bean lineages regarding the use and response to phosphorus available in nutrient solution

The objectives of this work were to evaluate the genetic variability of bean lineages in relation to phosphorus accumulation in plant tissues and yield, in addition to identifying efficient bean lineages in the use of phosphorus and responsive to the application of phosphorus in the crop environment. Work was carried out at Plant Science Department of the Federal University of Santa Maria. Concentrations of phosphorus in the nutrient solution between 1.33 and 1.84 mmol L-1 provide higher dry mass of pods, grains, number of grains and grain yield for the cultivars Pérola and IPR88 Uirapurú in the growing seasons autumn-winter and spring-summer. Concentrations between 1.37 and 1.96 mmol L-1 have the highest values of phosphorus in plant tissues, grain yield and phytic acid. Characteristics dry matter of leaves, stem and pods in pod filling, dry matter of grains on maturation, number of grains, number of pods and phosphorus concentration in plant tissues at the pod filling stage are promising because it allows for indirect selection. The nutritional value of leaves in young plants, for phosphorus, equivalent to that of grains. There is genetic variability among the bean lineages studied, for the production of dry mass, yield and accumulation of phosphorus in the tissues. Lineage L 2527 showed to be efficient and responsive to the use of phosphorus for the shoot of the plant. Lineage L 2225 showed to be efficient in the use of phosphorus in shoot, grains and grain production, besides maintaining this characteristic in the two growing seasons. 


Introduction
Beans (Phaseolus vulgaris L.) are widely distributed in Brazil because of their good adaptation to the most varied edaphoclimatic conditions (Pereira et al., 2010). The importance of the crop goes beyond the economic aspect, playing a fundamental role in the food of Brazilians, and in the demand for labor for being part of the most diversified production systems, with small, medium and large farmers (Barbosa & Gonzaga, 2012). Development, v. 9, n. 11, e3999118850, 2020 (CC BY 4.0) | ISSN 2525-3409 | DOI: http://dx.doi.org/10.33448/rsd-v9i11.8850 4 A considerable factor that limits the nutrition of bean plants and disfavor to obtain high grain yields is the low availability and mobility of phosphorus (P) in Brazilian soils (Leal, Prado, 2008). The great majority of national soils are acidic, with low fertility and high phosphorus retention capacity (Novais & Smyth, 1999).
Among minerals, phosphorus is a non-renewable, finite-source resource that often limits crop production (Oliveira et al., 2012). It is a chemical element, which naturally is contained in sedimentary, igneous and biogenetic rocks (Martins et al., 2014). In 2010, the International Fertilizer Development Center conducted a study to assess world phosphate reserves and resources and found that phosphate reserves are low. The reserves of Morocco and Western Sahara are considered the largest on the planet, and have been reduced from 50 billion tonnes to 5.7 billion in the last decade.
Excessive use of correctives and phosphate fertilizers leads to increased production costs, a fact that has been largely avoided (Carvalho et al., 2019). As an alternative to avoiding too much application of phosphate fertilizers, which is an obstacle to plant production, there is the development of efficient cultivars in the absorption and utilization of phosphorus (Hinsinger, 2001). The effects of elemental deficiency can be minimized when using some practices such as correction of soil acidity, adequate phosphate fertilization and the use of efficient cultivars in the use of phosphorus. In this way, it is highlighted the search for the genetic potential of plants with the efficient use of minerals. The development and identification of efficient and responsive bean cultivars to phosphorus can be a strategy to obtain high grain yields, without increasing the costs of the productive system. Among the factors that contribute to this, there is plant breeding, through which superior cultivars are obtained (Bertoldo et al., 2009;Carvalho et al., 2016).
At present, economic and environmental challenges are addressed in the efficient use of nutrients (Baligar et al., 2001). Due to the small capacity of the phosphatic rocks in the world, the best use of these reserves is fundamental to maintain and increase agricultural production (Cordell et al., 2009). The efficient use of nutrients enables losses to be minimized without damaging air and water quality (eutrophication), especially of nitrogen (N) and phosphorus (P) (Srinivasar, 2006). Essential and much explored by genetic breeding programs, the genetic variability between plants allows expressing genetic potential through selection (Bernardo, 2002). There are several proofs of plant species variability in nutrient utilization and absorption (Rao, 1996;Natani, 1996). As for phosphorus efficiency, different crops have already been evaluated as rice (Rotili et al., 2010); wheat (Silva et al., 2008) corn (Carvalho et al., 2012) and beans Research, Society and Development, v. 9, n. 11, e3999118850, 2020(CC BY 4.0) | ISSN 2525-3409 | DOI: http://dx.doi.org/10.33448/rsd-v9i11.8850 (Oliveira et al., 1987. Fageria (1998), concluded that there is great genetic variability among bean genotypes, which presented different behavior regarding the phosphorus utilization efficiency. It is known that this difference in selection of genotypes for phosphorus efficiency and grain yield is related to the translocation of the nutrient from the roots to the shoot (Lana et al., 2006).
The term nutritional efficiency is used to characterize the ability of plants to absorb and utilize nutrients, being related to the efficiency of their absorption, utilization and translocation (Amaral et al., 2011). This efficiency refers to the amount of dry matter or grains produced per unit of nutrient applied, and its optimization is of great importance in the production of plant species (Fageria, 1998). Therefore, to increase yield and reduce the cost of production, it is necessary to improve nutritional efficiency (Carvalho et al., 2019).
Phosphorus-efficient plants are those that produce the highest amount of dry mass per unit of absorbed phosphorus (Tomaz & Amaral, 2008). The concept of plant efficiency in the use of a nutrient encompasses processes by which plants absorb, translocate, accumulate and better utilize said nutrient for the production of dry matter and grains under normal nutritional conditions or with a limited supply of the nutrient in question. Föhse et al. (1988) defined the efficiency in the use of phosphorus as being the ability of a plant to produce a certain percentage of the maximum production with the lowest consumption of phosphorus.
The efficiency of the use of phosphorus by the plant is related to several internal and external mechanisms, such as aspects of root morphology, chemical changes in the rhizosphere, changes in the physiological characteristics of absorption kinetics, changes in biochemical processes, genetic variability and interactions with microorganisms that inhabit the soil (Lynch, 2007). In addition, it can be expressed and calculated in different ways, the index being proposed by Siddiqui e Glass (1981) is the most used to evaluate the efficiency in the use of nutrients, because it relates the efficiency in the use to the growth of the plants. Ramos et al. (2010) by evaluating the use of phosphorus and the production of bean grains, when cultivated in succession to forage grasses fertilized with different sources of this nutrient, used the Siddiqu e Glass index; to determine the efficiency of mineral use. Likewise, Procópio et al. (2005), also used the same index, when studying the efficiency in the absorption and use of phosphorus by soybean and bean crops and by weed species.
However, the response of the plants to the application is aimed at the observation of the behavior of the lineages in contrasting environments regarding the availability of the nutrient. This response is estimated by the relation between the production and biomass Development, v. 9, n. 11, e3999118850, 2020 (CC BY 4.0) | ISSN 2525-3409 | DOI: http://dx.doi.org/10.33448/rsd-v9i11.8850 differences and the availability of the nutrient, being originally considered for phosphorus by Fox (1978) and adapted by Furtini (2008) for the production of grains.
Furthermore, bean plants are considered to be poorly efficient in the absorption of this nutrient due to the low influx and requirement of phosphorus for the production of biomass (Fohse et al., 1988). The selection of bean cultivars that have a greater efficiency in the use of phosphorus becomes a useful and viable alternative for crops installed under conditions of low availability of this nutrient.
Thus, the objectives of this work were to evaluate the genetic variability of bean lineages in relation to phosphorus accumulation in plant tissues and yield, in addition to identifying efficient bean lineages in the use of phosphorus and responsive to the application of phosphorus in the crop environment.

Material and Methods
The experimental study was carried out in an explanatory manner, seeking to identify and explain factors that determine or contribute to the occurrence of phenomena (Pereira et al., 2018). The work was carried out at the Plant Science Department of the Federal At each growing season there were four closed off-soil cultivation devices, which were constructed and described by Domingues et al. (2014). On top of those, a total of 48 black Research, Society and Development, v. 9, n. 11, e3999118850, 2020 (CC BY 4.0) | ISSN 2525-3409 | DOI: http://dx.doi.org/10.33448/rsd-v9i11.8850 7 polypropylene vats, with a capacity of 4 L, were filled with a layer of gravel and medium sand and seeding was carried out. In two devices the plants were fertirrigated with nutrient solution containing the low concentration of phosphorus (0.9 mmol L -1 ) and in the other two, with the solution containing the high concentration of phosphorus (1,9 mmol L -1 ). In the low and high phosphorus solutions, nitrogen was added 0.9 mg L -1 and 2.4 mg L -1 (NH4 NO3 formulation).
Every 20 days all solutions were redone and the pH and electrical conductivity (EC) of these were measured three times a week. The pH was maintained in the range of 5.5 to 6.5 by the addition of NaOH or H2 SO4 when the solution was outside this stipulated limit. The electrical conductivity was preserved between 1.0 and 1.5 mS, adding water or new solution aliquots when outside this range. The plants were fertigated with the aid of drip hoses interconnected to the closed circuit. In this way, the solutions were provided individually for each device, in three daily shifts of fertigation during the autumn / winter, and with four shifts in spring / summer, each lasting 15 minutes.
When the plants were at the development stage of pod filling (R8), according to the phenological scale described by Fernandez et al. (1982), two plants of each lineage were collected in each of the closed devices. Totalizing the withdrawal of four fertirrigated plants with the low concentration of phosphorus and four, with the high concentration. These were fractionated and, separately, leaves, stem and pods were packed in paper bags, transported to a forced circulation oven (Odontobras 1.5; Odontobras, São Paulo, Brazil) until a constant mass was obtained, determined the dry mass of the tissues, with the aid of a digital scale. On reaching maturation stage (R9), new plants were collected (two plants of each lineage) and of these, the number of pods per plant, the number of grains per pod and the grain yield per plant were quantified at 13 % humidity.
In order to determine the phosphorus concentration in the plant tissues, samples of leaves, stem and pods in R8 and grains in R9 were milled using an analytical knife micro-mill (Q298A21; Quimis, São Paulo, Brazil), until a flour with particles of approximately 1 mm was obtained. From these samples aliquots of 0.5 g were digested in 5 ml of acid solution composed of nitric acid (HNO3) and perchloric acid (HClO4), in the ratio 3:1, as Research, Society and Development, v. 9, n. 11, e3999118850, 2020 (CC BY 4.0) | ISSN 2525-3409 | DOI: http://dx.doi.org/10.33448/rsd-v9i11.8850 8 recommended by Miyazawa et al. (1999). The concentration of phosphorus, expressed in g kg -1 of sample dry matter, was determined by reading in an optical emission spectrophotometer (AA-7000; Shimadzu, São Paulo, Brazil), with a wavelength of 660 nm.
The efficiency of phosphorus use was determined using the following indexes proposed and adapted by Siddiqui e Glas (1981)  Based on the phosphorus efficiency indexes and response to the application of phosphorus in the nutrient solution, graphs were made relating the efficiency and the responsiveness of the lineages. Thus, the classification of bean lineages into efficient and responsive (ER), non-efficient and responsive (NER), non-efficient and nonresponsive Research, Society and Development, v. 9, n. 11, e3999118850, 2020 (CC BY 4.0) | ISSN 2525-3409 | DOI: http://dx.doi.org/10.33448/rsd-v9i11.8850 9 (NENR) and efficient and nonresponsive (ENR) was performed according to Batten et al. (1984).
The statistical analysis of the data was performed, considering all effects as fixed, except for the error that was random, with the aid of the Microsoft® Office Excel spreadsheet and the Sisvar software (Ferreira, 2011). The data were submitted to analysis of variance, considering three replicates. As the effect of the significant triple interaction, the deployment of the three double interactions was performed. When the significance of the double phosphorus concentration interaction in the nutrient solution x genotype (C x G) or genotype x growing season (G x E) occurred, the Scott-Knott test at 5% error probability was used for the comparison of the means. In the cases where there was a significance of the double interaction that included phosphorus concentration in the nutrient solution x growing season (C x E), Student's t test was used, at 5% probability for comparison of means.

Results and Discussion
In the analysis of variance, for all growth traits, phosphorus production and accumulation in the tissues, there was a significant interaction between the phosphorus concentration x genotypes x growing season (C x G x E), except for the phosphorus variable in the pod. (Appendix E). The same occurred for the isolated effects of the concentration of phosphorus in the nutrient solution, genotypes and growing season. This evidences the influence on the availability of phosphorus, the genetic variability among the bean lineages studied and the variation between the growing seasons on these characters.
Also, there were significant double interactions, phosphorus x genotype concentration, phosphorus x growing season, genotype x growing season, for the growth traits (dry mass of the stem-DMStem and dry mass of the pods DMPod) and productive characters (number of pods per plant-NPod, number of grains per plant-NGrain and grain yield -Yield) (Appendix E). Similar behavior was observed for the characters of phosphorus accumulation in the leaves (PLeaf), the stem (PStem), the pods (PPod) and the grains (PGrain). The exception occurred in the double interaction, concentration of phosphorus x growing season, for leaf dry matter (DMLeaf) and phosphorus accumulation in plant tissues. Different results were found by Fageria (1998), when evaluating the efficiency of phosphorus use in 15 bean genotypes at low, medium and high levels in a Red-Dark Latosol. The author concluded that, for the characters of shoot dry mass and accumulation of phosphorus in the shoot, the dose interaction of phosphorus x genotypes was not significant, so that the genotypes analyzed Development, v. 9, n. 11, e3999118850, 2020 (CC BY 4.0) | ISSN 2525-3409 | DOI: http://dx.doi.org/10.33448/rsd-v9i11.8850 showed stability of adaptation, both for the low as for the high phosphorus level. However, Lana et al. (2006), studying eight bean genotypes regarding the efficiency of phosphorus uptake and utilization in the nutrient solution, detected significance in the interaction between phosphorus x genotype concentration for the characteristics of shoot dry mass and accumulation of phosphorus in shoot.
In relation to the phosphorus efficiency indexes in the shoot of the plant (EUShoot), grains (EUGrain), plants (EUPlant) and production (EUProd), all double interactions (C x G, C x E and G x E) and triple (C x G x E) were significant (Table 1). Thus, because the phosphorus concentrations in the nutrient solution are distinct, it is evident the possibility of selection of bean lineages for low and high phosphorus cultivation. In addition, there is genetic variability among the studied lineages, allowing selection for phosphorus efficiency. Table 1 -Analysis of variance for the efficiency of phosphorus in the shoot (EUShoot, g 2 mg -1 ), efficiency in the use of phosphorus in grains (EUGrain, g 2 mg -1 ), efficiency in the use of phosphorus in the plant (EUPlant, g 2 mg -1 ), and efficiency in the use of phosphorus in grain production (EUProd, g 2 mg -1 ); Phosphorus index of response to shoot dry matter production (IRShoot), phosphorus index of response to grain yield (IRGrain) and phosphorus index of response to the production of dry mass in the plant (IRPlant); evaluated in 12 bean genotypes, submitted to two concentrations of phosphorus in the nutrient solution in two growing seasons. Santa Maria -RS, UFSM. For the indexes of phosphorus response in shoot (IRShoot), grain (IRGrain) and plants (IRPlant), the genotype x growing season interaction (G x E) presented significance, so that it is possible to verify that the bean lineages presented a response regarding the application of phosphorus differentiated by virtue of the growing season (Table 1) The results showed that the yield of phosphorus was higher than that of the cultivar. Knowing that response to fertilization is associated with the capacity to increase biomass production with the highest nutrient supply (Fidelis et al., 2005;Vargas et al., 2018) and that, when the plant is cultivated, it also exerts influence on biomass production, there is a clear difference between the environments. The radiation, which was distinct in the two growing seasons, is one of the climatic factors that has a direct influence on the biomass production in the bean crop, since it is directly related to the photosynthetic rate of the plants (Teixeira et al., 2015).
When considering the average values of the growth characters shown in Table 2, it can be seen that for the production of dry mass in the leaves, the lineages L 2225, L 2632 and L 2527 constituted the group of the highest averages in the low concentration of phosphorus, which did not occur in the high concentration. With the exception of the lineage L 2527, which formed the group with the highest averages for this character in both the low P and the high P, indicating good adaptation to both environments. In both growth and yield characters, the general averages of all genotypes studied were lower in nutrient solution with low phosphorus and higher in high phosphorus (Table 2).
Knowing the existence of the direct relationship between the production of biomass and the final productivity, the condition that favors plant growth, also leads to higher production. The decrease in the biomass production under the lowest phosphorus concentration is related to the high carbohydrate partition allocated to the roots in phosphorus-deficient plants (Fontes, 2016). This fact can be explained, because plants developed with low concentrations of phosphorus present a lower content of total soluble carbohydrates and reducing sugars in the composition of their vegetal tissues, in this way, the less they develop (Coutinho et al., 2000). Table 2 -Mean values obtained for the characters dry mass of the stem (DMStem, g), leaves (DMLeaf, g), pods (DMPod, g); number of pods (NPod), number of grains (NGrain) and grain yield (Yield, g plant -1 ), obtained for 12 bean genotypes, submitted to two concentrations of phosphorus (Low P -0.9 mmol L -1 and High P -1.9 mmol L -1 ) in the nutrient solution. Santa Maria -RS, UFSM.   (1998), efficient cultivars in the use of the mineral usually decrease their production with the increase of nutrient levels; this means that phosphorus utilization efficiency is highest at the lowest nutrient level and lowest at the highest level. Table 3 -Mean values for the phosphorus concentration in the stem (PStem, g kg -1 of dry matter -DM), leaves (PLeaf, g Kg -1 of DM), pods (PPod, g Kg -1 of DM) and in the grains (PGrain, g Kg -1 of DM), obtained for 12 bean genotypes, submitted to two phosphorus concentrations (low P = 0.9 mmol L -1 and high P = 1.9 mmol L -1 ) in the nutrient solution. Santa Maria -RS, UFSM. In Table 3  Only the lineages L 2527 and L 2225 repeated the behavior for the phosphorus efficiency in the shoot of the plants, since they were efficient in both growing seasons (autumn-winter: season 1, spring-summer: season 2), Figure 1A and 1B, respectively. Therefore, these genotypes produce above average in low phosphorus concentration in the growing season. The preference for cultivars with wide adaptation to the various growing environments should be considered (Carbonell et al., 2001;Szareski et al., 2017). Fageria (1998, when evaluating the 15 bean genotypes in the use of phosphorus in a Dark Red Latosol, also found that the genotypes showed a different behavior in relation to the efficiency of phosphorus use, with Rio Doce, São José, IPA 9, Aporé, Goytacazes, Carioca-MG, Research, Society and Development, v. 9, n. 11, e3999118850, 2020 (CC BY 4.0) | ISSN 2525-3409 | DOI: http://dx.doi.org/10.33448/rsd-v9i11.8850 16 Carioca-IAC, Serrano, Safira and Roxo 9 being considered efficient in the use of phosphorus in the shoot. Figure 1 -Classification of 12 bean genotypes regarding the efficiency in the use of phosphorus in the shoot (EUShoot, g 2 mg -1 ) in relation to the phosphorus index of response to shoot dry mass production (IRShoot, g mg -1 ) and phosphorus efficiency in grains (EUGrain, g 2 mg -1 ) in relation to the phosphorus index of response in grains (IRGrain, g 2 mg -1 ) obtained in low concentration of phosphorus in nutrient solution in two crops (autumn / winter -Season 1 and spring / summer -Season 2). Santa Maria -RS, UFSM.
Although the lineage L 2527 has been highlighted as efficient and responsive in the use of phosphorus to the shoot, that is to say, having produced greater biomass of shoot in the lower concentration of phosphorus in the solution and to have responded positively to the increment of the nutrient, this did not make the plant convert biomass into production, and the  Figures 2A and 2B).This result corroborates those found by Zucarelli et al. (2011), in order to identify genetic effects that control the inheritance of characters associated to phosphorus utilization efficiency in beans, performed a study with two levels of phosphorus availability (high and low). The efficiency of use, in low phosphorus availability, did not correlate with grain yield. However, under high nutrient availability, these parameters correlated. ER: efficient and responsive; NER: not efficient and responsive; NENR: not efficient and non responsive and ENR: efficient and non responsive. 1 -L2244; 2 -L2519; 3 -L2527; 4 -L2411; 5 -L2625; 6 -IPR88 Uirapurú; 7 -L2528; 8 -L2225; 9 -Pérola; 10 -L2632; 11 -L2637 and 12 -L2428. Source: Authors. However, the lineage L 2225, which showed to be efficient in the use of phosphorus in the shoot (EUShoot) (Figures 1A and 1B), and grains (EUGrain) (Figures 1C and 1D) and maintained this characteristic in the two growing seasons, was also present, in the growing seasons 1 and 2, in the efficient group but not responsive to the use of phosphorus in the production of grains (Figures 2A and 2B). This lineage, along with 2244, 2411, IPR88 Uirapurú (in season 1), 2528, Pérola, 2632, 26,37 and 2428 (season 2) and 2625 (seasons 1 and 2) were the most efficient in the conversion of phosphorus for production in low availability of phosphorus, so they are promising for cultivation in phosphorus restricted environments and may be useful for breeding programs aiming at phosphorus efficiency in beans. Among the characteristics considered favorable in a bean genotype that is efficient in the use of phosphorus, the translocation of the phosphorus from the roots to the growing tissues and a suitable reproductive development, so that more possible amount of phosphorus is used in the grain production are included (Youngdahl, 1990).

Final Considerations
Concentrations of phosphorus in the nutrient solution between 1.33 and 1.84 mmol L -1 provide higher dry mass of pods, grains, number of grains and grain yield for the cultivars Pérola and IPR88 Uirapurú in the growing seasons autumn-winter and spring-summer.
However, the concentrations between 1.37 and 1.96 mmol L -1 have the highest values of phosphorus in plant tissues, grain yield and phytic acid.
The characteristics dry matter of leaves, stem and pods in pod filling, dry matter of grains on maturation, number of grains, number of pods and phosphorus concentration in plant tissues at the pod filling stage are promising because it allows for indirect selection. The nutritional value of leaves in young plants, for phosphorus, is equivalent to that of grains.
There is genetic variability among the bean lineages studied, for the production of dry mass, yield and accumulation of phosphorus in the tissues. The lineage L 2527 showed to be efficient and responsive to the use of phosphorus for the shoot of the plant. Lineage L 2225 showed to be efficient in the use of phosphorus in shoot, grains and grain production, besides maintaining this characteristic in the two growing seasons.
Studies like this should be of paramount importance and should be valued.