**2. Production of soybeans in Northeast Brazil**

The Northeast region of Brazil is situated between latitudes 1°20'00'' and 19º00'00'' S. Maturi‐ ty groups adapted to this region range from maturity group 7 to 9.Examples of cultivars de‐ veloped for this region are BRS 326 (maturity group 8.7) and BRSMA Seridó RCH (9.7). Both cultivars have the long-juvenile trait which reduces the photoperiod sensitivity to the short days of this region; thus allowing soybean to have an adequate developmental period for optimal yield. Much of the success of soybean expansion into Northeast Brazil is due to the development of cultivars having the long-juvenile trait [3]. Development of these cultivars was done through breeding programs using the following cultivars and genotypes: PI 240664, PI 159925, Santa Maria, PR Paranagoiana 77-10001 [24, 20]. Experimental studies in the past century, especially in the United States, led to the classification of soybeans into ma‐ turity groups based on their photoperiod response. The maturity groups were: classify groups of soybean according to the response to photoperiod, a total of 13 classes of matura‐ tion, which are 000, 00, 0, I, II, III, IV, V, VI, VII, VIII, IX and X [27, 35].

Besides the issue of photoperiodism, soybean expansion into Northeast Brazil is also limited by drought, waterlogging, the harsh environment of the Amazon region, infrastructure, marketing, and the availability of manual labor [11]. Cultivar development was initiated in Piaui state in 1972 and resulted in the release of cultivar Tropical in 1980.This was followed by the development and release of more cultivars for production in Northeast Brazil [3]. Ex‐ amples are the cultivars DM-Soberana and DM-Nobre released in the central region of Bra‐ zil in the states of Bahia and Maranhão. These cultivars were well adapted to the tropical conditions of this region, demonstrated greater yield than check cultivars, had good yield stability across environments, proper maturity for the growing season, and were adapted for mechanical harvest [39]. In the states of Maranhão, Piauí and Tocantins, a new cultivar, BRSMA-Babacu, was developed for commercial production. Across seven environments in the late 1990's, it demonstrated an average yield of 2,952 kg/ha which was 4% higher than the local cultivar Doko Millionario. It is a late-maturing cultivarwith a maturity of 130 days from emergence to maturity, a plant height of 99 cm, moderately resistant to lodging, purple flower color, brown pod and pod pubescence, yellow seed coat, brown hilum, good resist‐ ance theto pod dehiscence, average seed quality and average seed weight of 15.8 g/100 seeds [23]. In these states, the time of planting depends on the rainy season, which occurs in summer (Table 1).


**Table 1.** Sowing dates for soybean state and the northeast.

for northeastern Brazil between 1982 and 1998 are: Timbira; BR 10 (Teresina) and BR 11 (Carajás); BR-27 (Cariri) and BR-28 (Seridó); BR- 32 (Nova Tropical); BR/ EMGOPA 312 (Po‐ tiguar) and BR 35 (Rio Balsas); Embrapa 9 (Bays); Embrapa 30 (Vale do Rio Doce), Embrapa 31 (Mina), Embrapa 33 (Cariri RC) and the Embrapa 34 (Teresina RC); Embrapa 63 (Mira‐ dor); MA/BR 64 (Parnaíba) and MA/BR 65 (Sambaíba) and MA/BRS-164 (Patí) and MA/

A Comprehensive Survey of International Soybean Research - Genetics, Physiology, Agronomy and Nitrogen

Characteristics that have been selected for production in low latitude areas are: suitable ma‐ turity, adequate plant height, height to first pod of more than 12 cm ,a non-woody stem, erect plant stature, lodging resistance, pest resistance, good seed quality and high oil content and protein content, high yield, yield stability (robustness), uniform ripening, indehiscent pods, high capacity for N2 fixation, tolerance to aluminum and manganese toxicity, a long juvenile phase and photoperiod insensitivity. Across planting dates and environments, the growing season can vary from 75 to 200 days. Thus a wide range of cultivars have had to be developed for adaptation to many environmental conditions [22, 43]. The average height of the plant can range from 20 to 150 cm or more, according to the cultivar and environment, and the height to first pod may be characteristic of the cultivar. Environmental factors or cultural practices may also affect height to first pod [35], which prevents mechanical har‐

The Northeast region of Brazil is situated between latitudes 1°20'00'' and 19º00'00'' S. Maturi‐ ty groups adapted to this region range from maturity group 7 to 9.Examples of cultivars de‐ veloped for this region are BRS 326 (maturity group 8.7) and BRSMA Seridó RCH (9.7). Both cultivars have the long-juvenile trait which reduces the photoperiod sensitivity to the short days of this region; thus allowing soybean to have an adequate developmental period for optimal yield. Much of the success of soybean expansion into Northeast Brazil is due to the development of cultivars having the long-juvenile trait [3]. Development of these cultivars was done through breeding programs using the following cultivars and genotypes: PI 240664, PI 159925, Santa Maria, PR Paranagoiana 77-10001 [24, 20]. Experimental studies in the past century, especially in the United States, led to the classification of soybeans into ma‐ turity groups based on their photoperiod response. The maturity groups were: classify groups of soybean according to the response to photoperiod, a total of 13 classes of matura‐

Besides the issue of photoperiodism, soybean expansion into Northeast Brazil is also limited by drought, waterlogging, the harsh environment of the Amazon region, infrastructure, marketing, and the availability of manual labor [11]. Cultivar development was initiated in Piaui state in 1972 and resulted in the release of cultivar Tropical in 1980.This was followed by the development and release of more cultivars for production in Northeast Brazil [3]. Ex‐ amples are the cultivars DM-Soberana and DM-Nobre released in the central region of Bra‐ zil in the states of Bahia and Maranhão. These cultivars were well adapted to the tropical

BRS-165 (Seridó RCH).

Relationships

378

vesting and can cause harvest loss.

**2. Production of soybeans in Northeast Brazil**

tion, which are 000, 00, 0, I, II, III, IV, V, VI, VII, VIII, IX and X [27, 35].


In each column, the same letter not differ at 5% probability by Tukey test.

**Table 2.** Number of days to flowering (NDF), number of days to fruit set (NDFT), reproductive period (RP), plant height at maturity (ALTM), number of nodes / plant (NPP) Observed in different cultivars of soybean-green. Sand-PB, UFPB, 2004.

Research conducted in the Brazilian states located in Northeast Brazil have shown promis‐ ing results regarding the adaptation of cultivars to cultivation. Research conducted at the Federal University of Paraiba, Center for Agrarian Sciences, resulted in the development of cultivar Pirarara. This cultivar was adapted to the Entisol soils of the region, as well as the sort days, warm and humid climate, rainfall, and acid soils. It had a plant height of about 63

cm and developed about 12 main stem nodes. Days from emergence to maturity was about 75. Data for the cultivar is shown in Table 2 [40]. Further research with this cultivar demon‐ strated that when intercropped with corn, it had a vegetative period (days from planting to first flower) of about 55 days. This was a sufficient period to allow for enough dry matter accumulation to optimize yield. Other developed cultivars had shorter vegetative periods, such as Pati (50 days) and JLM 004 (39 days).The significant factor is to allow enough time for node production, since nodes are plant structures from which pods, seeds, and yield are made. This has been demonstrated in research conducted by [19] in which yield was shown to be related to the number of nodes formed. Cultivar Black Alliance had the most at 33, while Kanro had the fewest at 8.


**Table 3.** Average linear regression coefficient ( li), misuse of linear regression ( ij) and coefficient of determination (R2) According to the methodology of Eberhart and Russell (1996) for grain production of soybean genotypes in Ceará.

Although production of soybean is still restricted in some areas for the northeastern states of Bahia, Maranhão and Piauí, it has shown potential for expansion for other states in the re‐ gion such as Ceará. Near the city of Pentecost (3o 47' S Latitude), cultivar trials during 2005 and 2005 have identified genotypes BRS TRACAJÁ, and BRS Sambaíba MA BR 97 1665as having potential to be grown in Ceará (Table 3). Certain soybean cultivars, when intercrop‐ ped with corn, were capable of producing large biomass relative to other cultivars [42].

Preliminary testing of three soybean cultivars is being conducted by [9] in the coastal plains in the state of Alagoas, near the city of Rio Largo, at a latitude of 9°29'45''. Cultivars used in the study were MG / BR - 46 (Conquista), and BRS Tracajá MA/BRS-165 (Seridó RCH). Agro‐ nomic data for plant height is shown in Table 4 and data for yield and seed weight is in Table 5.Although plant height was somewhat lower than that which is usually required for mechanical harvesting, [9] demonstrated that yield production was good for all cultivars ranging from 2,620 to 3,600 kg ha-1 (Table 5), being equal to or superior to the traditional re‐ gions of production soybean.


Source: [9]

cm and developed about 12 main stem nodes. Days from emergence to maturity was about 75. Data for the cultivar is shown in Table 2 [40]. Further research with this cultivar demon‐ strated that when intercropped with corn, it had a vegetative period (days from planting to first flower) of about 55 days. This was a sufficient period to allow for enough dry matter accumulation to optimize yield. Other developed cultivars had shorter vegetative periods, such as Pati (50 days) and JLM 004 (39 days).The significant factor is to allow enough time for node production, since nodes are plant structures from which pods, seeds, and yield are made. This has been demonstrated in research conducted by [19] in which yield was shown to be related to the number of nodes formed. Cultivar Black Alliance had the most at 33,

A Comprehensive Survey of International Soybean Research - Genetics, Physiology, Agronomy and Nitrogen

**Cultivars Mean (kg ha-1) li** ij **R2** BRS TRACAJÁ 1882,87 0,52\*\* 792,69\*\* 99,25 BR JUÇARA 1555,41 1,84\*\* 145934,72\*\* 90,12 BRS MA 165 SERIDÓ 1511,10 1,04ns 21982,14\*\* 95,07 BRR 219 BOA VISTA 1585,36 1,14ns 30844,36\*\* 94,35 BRS SAMBAÍBA 1893,58 0,94ns 145903,06\*\* 70,40 BRS CANDEIA 1552,88 0,91ns 10589,73\*\* 75,27 MA BR 971665 1725,72 0,61\*\* 14432,72\*\* 91,06

ns not significant; \* Significant at 5% probability level; \*\* Significant to 1% probability by the F test

**Table 3.** Average linear regression coefficient ( li), misuse of linear regression ( ij) and coefficient of determination (R2) According to the methodology of Eberhart and Russell (1996) for grain production of soybean genotypes in Ceará.

Although production of soybean is still restricted in some areas for the northeastern states of Bahia, Maranhão and Piauí, it has shown potential for expansion for other states in the re‐

and 2005 have identified genotypes BRS TRACAJÁ, and BRS Sambaíba MA BR 97 1665as having potential to be grown in Ceará (Table 3). Certain soybean cultivars, when intercrop‐ ped with corn, were capable of producing large biomass relative to other cultivars [42].

Preliminary testing of three soybean cultivars is being conducted by [9] in the coastal plains in the state of Alagoas, near the city of Rio Largo, at a latitude of 9°29'45''. Cultivars used in the study were MG / BR - 46 (Conquista), and BRS Tracajá MA/BRS-165 (Seridó RCH). Agro‐ nomic data for plant height is shown in Table 4 and data for yield and seed weight is in Table 5.Although plant height was somewhat lower than that which is usually required for mechanical harvesting, [9] demonstrated that yield production was good for all cultivars ranging from 2,620 to 3,600 kg ha-1 (Table 5), being equal to or superior to the traditional re‐

47' S Latitude), cultivar trials during 2005

while Kanro had the fewest at 8.

Source: [10]

Relationships

380

CV (%) 22,52 General mean (kg ha-1) 1672,42

gion such as Ceará. Near the city of Pentecost (3o

gions of production soybean.

Means Followed by the same letter not differ to the 5% level of probability by Tukey test.

**Table 4.** Height of plant growth stages R2 and R9 of three soybean varieties grown in the Coastal Plain region of the state of Alagoas.


Source: [9]

Means Followed by the same letter not differ at the 5% level of probability by the Tukey test.

**Table 5.** Grain yield and mass of 100 seeds of three varieties grown on Coastal Plain region of the state of Alagoas.

In research conducted by [5], agronomic performance of several soybean cultivars in the rugged areas of the states of Bahia and Sergipe (latitude 10°14'S and 10°55' S). There were two series of screening studies conducted, the first having 14 genotypes and the second hav‐ ing 24. The tests were conducted during the growing seasons of 2006 and 2007 in several cit‐ ies in remote rural areas of Sergipe and Bahia. Among the many cultivars tested, the ones performing the best were BRS SAMBAÍBA and EMGOPA, followed by BRS TRACAJÁ, BRS CONQUISTA, BRS BELA VISTA, BRS CORISCO and BRS BARREIRAS. All cultivars dem‐ onstrated a yield range of 2,285-3,373 kg/ha.

Studies with 18 soybean cultivars, performed by [28] in the state of Piauí, (Lat05°02'40 "S), were planted on 28 February 2010. Based on differences in days to first flower, the cultivars were separated into four groups (Table 6): early (45 to 47.7 days), medium (48-57), late (>57 days), and average.



Source: [28]

\* Means Followed by the same letter not differ by Scott-Knott test (P ≤ 0.05).

**Table 6.** Mean values for the number of days to flowering (NDF), number of days to maturity (NDM), reproductive period in days (PR) and percentage (RP%) of different soybean genotypes Evaluated in low latitude, in Teresina - PI.

[28] reported excellent yields with genotypes 171BCR1069X7RG and 174 BCR1069X7RG. They both produced yields of about 4000 kg ha-1. These were much better than other geno‐ types, the lowest of which yielded below 2000 kg ha-1 (Table 7).



\* Means followed by same letter do not differ by Scott-Knott test (P ≤ 0.05)

**GENOTYPES**\* **Cycle (days) Classification**

\* Means Followed by the same letter not differ by Scott-Knott test (P ≤ 0.05).

types, the lowest of which yielded below 2000 kg ha-1 (Table 7).

171 BCR1069X7RG 4,188.53 A 174 BCR1069X7RG 3,838.66 A 170 BCR1069X7RG 3,464.27 B 177 BCR1069X7RG 3,248.29 B 169 BCR1069X7RG 3,084.99 B 175 BCR1069X7RG 2,802.35 C

**GENOTYPES**\* **PRODUCTIVITY (kg ha-1)**

**Table 6.** Mean values for the number of days to flowering (NDF), number of days to maturity (NDM), reproductive period in days (PR) and percentage (RP%) of different soybean genotypes Evaluated in low latitude, in Teresina - PI.

[28] reported excellent yields with genotypes 171BCR1069X7RG and 174 BCR1069X7RG. They both produced yields of about 4000 kg ha-1. These were much better than other geno‐

Source: [28]

Relationships

382

**cycle**

BRS CANDEIA 48.25 C 117.00 E Medium 66.50 A 55.64 A BRS 219 BOA VISTA 46.25 D 101.25 I Early 56.00 C 47.14 B BRS 271RR 45.75 D 104.50 H Early 60.00 B 48.62 B 114 BCR336F8 50.50 C 134.00 A Late 59.25 B 43.40 D 142 SOY94F5G 53.75 B 130.50 B Late 65.00 A 49.34 B 164 SOY94F5G 51.00 C 114.50 F Medium 55.50 C 45.63 C 168 BCR1069X7RG 53.25 B 120.75 D Medium 55.50 C 45.30 C 169 BCR1069X7RG 45.00 D 121.25 D Medium 55.50 C 45.31 C 170 BCR1069X7RG 48.50 C 123.00 D Medium 50.00 D 39.52 E 171 BCR1069X7RG 50.25 C 120.25 D Medium 65.25 A 53.59 A 172 BCR1069X7RG 50.50 C 126.00 C Late 62.50 B 48.54 B 173 BCR1069X7RG 51.00 C 121.25 D Medium 56.75 C 46.32 C 174 BCR1069X7RG 47.75 D 122.75 D Medium 55.00 C 45.17 C 175 BCR1069X7RG 49.00 C 128.00 C Late 62.00 B 48.06 B 176 BCR1069X7RG 57.25 A 117.50 E Medium 63.00 B 48.64 B 177 BCR1069X7RG 58.00 A 114.00 F Medium 56.25 C 45.93 C 179 SOY24F5G 50.25 C 107.50 G Early 61.25 B 48.62 B C.V. (%) 4.62 1.55 5.16 4.85 General mean 50.29 118.77 58.91 47.33

A Comprehensive Survey of International Soybean Research - Genetics, Physiology, Agronomy and Nitrogen

**Reproductive period**

**Table 7.** Mean values of grain yield in different soybean genotypes evaluated in low latitude, Teresina - PI.

Research conducted in western Bahia, near the city of São Desidério (Lat 12o 45'S). Growth and yield of soybean at different planting dates are shown in Table 8. Although there were some planting dates at which all cultivars showed good yields, only cultivar M-SOY 8411 yielded well at all four planting dates [9].


**Table 8.** Average grain yield (kg / ha) from five soybean sown in times Ep1 (29/11/2006), Ep2 (12/14/2006) Ep3 (28/12/2006) and ep4 (01/12/2007), in western Bahia.

Data for Value for Cultivation and Use (VCU) of soybean BRS 278RR for the state of São Paulo indicated that it belongs to a medium maturity group (maturity group 9.4), with the number of days to maturity ranging from 115 to 127 days [26]. According to these authors, the average yield of soybean tested in 24 environments of evaluation was 2,973 kg/ha, and 5.2% more productive than the standard transgenic BRS 271RR, and 5% less productive than the conventional BRS tracajá (Table 9).


**Table 9.** Average grain yield (kg / ha) and relative yield (%) of BRS 278RR, BRS and BRS 271RR turtle in the agricultural years 2004/05 to 2006/07 of the southern regions of the Maranhão, Piauí southwestern and northern Tocantins.

Because of these pioneering studies to develop cultivars adapted to different regions of northern Brazil, soybean production has expanded rapidly throughout the region. For all the soybean growing regions of Brazil, the greatest expansion has occurred in the North and Northeast regions of the country [8]. Across the region, between the 2008/2009 growing sea‐ son to the 2009/2010 season, the area of production increased by 8.9% from 2,105,600 to 2,292,600 hectares. A more recent survey by [7] highlights the states of Bahia, Piauí and Mar‐ anhão. In the state of Piaui area there was a 16.6% increase in soybean acreage between 2011 and 2012, with the entire state having a production area of 447,300 hectares for soybean. In the state of Bahia, the largest producer of oilseeds in the Northeast, the area planted to soy‐ bean increased by 6.6%, from 1,040,000 to 1,110,000 hectares across the same period. The same type of expansion occurred in Maranhao where the growing area increased 12.2%, from 518,200 to 581,400 hectares.

Development of adapted cultivars for Northeast Brazil has greatly aided this expansion into tropical regions. This has made a significant contribution to strengthening the regional agri‐ cultural economy. Soybeans provides oil for the food industry and livestock meal for meat production, enhances agricultural development in undeveloped areas, and helps to add a protein-rich source of human food to ameliorate the widespread protein deficiencies com‐ mon to Northeast Brazil [3].
