Soybean (Glycine max (L.) Merr.) yield and disease incidence with potassium fertilization

Abstract

Six cultivars and three lines of soybean (Glycine max (L.) Merr.) were planted at two locations in Delaware in 1974 and 1975. Potassium fertilizer (KCl) at 0, 56, or 223 kg/ha actual K was added to the soil and the plants were evaluated for seed yield and incidence of gray‐moldy and purple‐stained seed.

Potassium application was related to a decrease in yield in one year at one location but had no significant effect in the other year or at the other location. Cultivars differed in yield over the two years, with Kent, Cutler 71, and York having the most consistent yield in this study. The pathogen incidence was not affected by potassium application in contrast to earlier studies with soybeans grown in aluminum cylinders with a partially restricted soil volume. In this study, gray‐moldy and purple‐stain was highest in short season cultivars and higher at Georgetown than at Newark.

Use of soybean cultivars resistant to diseases as well as maintaining adequate soil potassium levels should reduce high levels of disease.     

Lead-Induced Histological and Ultrastructural Changes in the Leaves of Soybean (Glycine max (L.) Merr.)

The seedlings of the soybean ( Glycine max. (L.) Merr.) cv. Polan were investigated by subjecting them to water culture for a period of 14 d. To the Knop nutrient solution, lead was added as PbCl₂ at four concentrations: 0, 10, 20 and 40 mg dm⁻³. Observations of soybean leaf tissues were carried out by light microscopy, transmission electron microscopy and scanning electron microscopy. The Pb levels used in the present study reduced the area of cotyledons and leaf blades of the soybean plants. Pb-induced changes in the leaf epidermis structure involved a reduction in the cell size, more abundant wax coating, and an increase in the number of stomata and trichomes per unit area with simultaneous reduction in the size of the guard cells. The lead treatment resulted in the reduction in the thickness of the leaf blades, reduction in the area of xylem and phloem in the vascular bundles and in the diameter of the xylem vessels. Under Pb stress, the leaf mesophyll cells were characterized by the presence of altered chloroplasts with a reduced lamellar system and multidirectional pattern of the thylakoid system. Burst stroma of the thylakoid system and cracked chloroplast envelopes were also observed. The importance of the increase in the number of stomata and trichomes for plants under the metal stress was examined.     

Differences in numbers of nodules and lateral roots between soybean (Glycine max L. Merr.) cultivars,Kitamusume and Toyosuzu

Two cultivars of soybean (Glycine max L. Merr .), Kitamusume and Toyosuzu were grown with commercially-purchased granulated soil in a greenhouse. Kitamusume formed a larger number of nodules per g shoot dry weight and its nodules showed a smaller average diameter and average dry weight per nodule than Toyosuzu regardless of plant age or rhizobial strains (Bradyrhizobium japonicum (AI017, J5033, 646, J1B140), B. elkanii (USDA94), and Rhizobium fredii (MAFF210054)) inoculated at the rate of 10⁸-10⁹ cells per 3 L pot. These differences were observed in the nodules formed on both primary and lateral roots. With a lower inoculation dose of rhizobia (10² and 10⁵ cells per pot), Kitamusume formed a smaller number of larger nodules than Toyosuzu inoculated with 10⁸-10⁹ cells per pot. This result indicated that the number of nodules was the factor directly controlled by host, because the size of the nodules was not determined by the genetic background, but changed depending on the number of nodules formed. The number of the first order lateral roots of 21 d old Kitamusume was 1.49 times larger than that of Toyosuzu. The relationship between the number of nodules and the number of first order lateral roots of 14 cultivars showed a significant positive correlation. These results indicated that the formation of nodules and lateral roots may be similarly controlled by a certain factor in different cultivars.     

Potassium fertilization effects on isoflavone concentrations in soybean [Glycine max (L.) Merr.

Soybean isoflavone concentrations vary widely, but the contribution of soil fertility and nutrient management to this variability is unknown. Field experiments from 1998 to 2000 on soils with low to high exchangeable potassium (K) concentrations evaluated K application and placement effects on isoflavone concentrations and composition of soybean in various tillage and row-width systems. Soybean seed yield and concentrations of daidzein, genistein, glycitein, leaf K, and seed K were measured. Significant increases in daidzein, genistein, and total isoflavone were observed with direct deep-banded K or residual surface-applied K on low-K soils. Positive effects of K fertilization on isoflavones were less frequent on medium- to high-testing K soils. Both individual and total isoflavones were often positively correlated with seed yield, leaf K, and seed K on low-K soils. Appropriate K management could be an effective approach to increase isoflavone concentrations for soybeans produced on low- to medium-K soils.     

Oxalate and phytate concentrations in seeds of soybean cultivars [Glycine max (L.) Merr.

This study analyzed soybean seeds from 116 cultivars for total, insoluble, and soluble oxalate (Ox), phytate (InsP6), calcium (Ca), and magnesium (Mg) because of their potential beneficial or harmful effects on human nutrition. These cultivars were divided into four groups (A-D) on the basis of the year and geographic location where they were grown. Oxalate concentration ranged from about 82 to 285 mg/100 g of dry seed. The InsP6 concentration ranged from 0.22 to 2.22 g/100 g of dry seed. There was no correlation between Ox and InsP6 within or among the four groups of cultivars. There was a significant correlation between total Ox and Ca, but not Mg, in group D cultivars (r = 0.3705; p < 0.0005). No significant relationship was found in the group A-C cultivars. Eleven group D cultivars had InsP6 less than 500 mg/100 g, but all had total Ox of 130 mg/100 g or greater. Five cultivars from groups A-C had relatively low InsP6 (group B; < or =1.01 g/100 g) and low Ox (<140 mg/100 g). These cultivars could be useful for producing soy foods beneficial to populations at risk for kidney stones and for improved mineral bioavailability. The Ox and InsP6 concentrations of the cultivars indicate that choosing specific parents could generate seeds in succeeding generations with desirable Ox and InsP6 concentrations.     

AFLP Analysis of Genetic Diversity in Indian Soybean [Glycine max (L.) Merr.] Varieties

AFLP technique was used to assess genetic diversity in 72 soybean varieties under cultivation in India. Selected 12 AFLP primer pairs produced 1319 products of which 1257 were polymorphic (95%). Wide variations were observed for the number of amplification products, percent polymorphism and average polymorphism information content (PIC). The Jaccard's similarity indices (J) based on the AFLP profiles of the 72 soybean varieties were subjected to UPGMA cluster analysis. The dendrogram generated revealed four major clusters, which were strongly supported by the high bootstrap values obtained from analyses of 1000 bootstrap samples. In addition, the Mantel's test for cophenetic correlation with r = 0.955 indicated very good fit of the varieties to a group in the cluster analysis. Some correspondence between the clustering pattern and the pedigree, place of release or target area of the variety was observed. Overall moderately high genetic diversity was observed which appears to be due to the higher genetic diversity prevalent in 12 of the varieties included in three diverse clusters and was indicative of the need to include more diverse germplasm in the soybean improvement programs.     

Seed Coat Cracking of Soybean (Glycine max [L.] Merr.) After Soaking and Cooking

Seed coat cracking after soaking (SCAS) and after cooking (SCAC) are unfavorable traits associated with soybeans for food uses, such as cooked and seasoned beans (nimame) and fermented steamed beans (natto) because they cause an inferior appearance of the products and clogging of the production lines. The variation and causes of SCAS and SCAC among cultivars have not yet been clarified, but if they are determined genetically, genetic modification could be possible. Cultivars showed considerable variations in SCAS and SCAC. Significantly positive seasonal correlations of SCAS (Spearman's rank correlation coefficient, ρ = 0.518) and of SCAC (ρ = 0.681) were observed among recombinant inbred lines (RILs) derived from the cross between cultivars Nattoshoryu and Hyokeikuro 3. Quantitative trait locus (QTL) analyses and statistical analyses using generalized linear models showed that QTLs for SCAS (qSCAS1 , qSCAS2 , and qSCAS3 ) and SCAC (qSCAC1 and qSCAC2 ) were located on chromosomes 4 (linkage group [LG]: C1), 6 (LG: C2), and 8 (LG: A2) of the RILs. Interactions between QTLs were also observed. SCAS and SCAC are traits controlled by QTLs, which could provide significant insight into their causes and mechanisms. These undesirable characteristics could be improved through breeding.     

Foliar fertilization of soybeans (Glycine max L.)

Abstract

The effects of foliar fertilizer applications to soybeans during seed‐filling were examined using a complete factorial design with four levels each of nitrogen (N), phosphorus plus potassium (P+K) and sulfur (S). Hodgson soybeans were planted in 76‐cm rows on a Piano silt loam (Typic Argiudoll) in 1976 and 1977. Four fertilizer spray applications were made at 7‐ to 10‐day intervals beginning at stage R₄ ². The application of N generally increased yield, seed weight, and percent N in the grain both years of the experiment. Phosphorus, K, and S had little influence on the parameters measured. Leaf burn after each fertilizer application was significantly increased by most levels of fertilizer addition.     

Soybean (Glycine max [L.] Merr.) shoots systemically control arbuscule formation in mycorrhizal symbiosis

The roots of soybean ( Glycine max [L.] Merr.) establish symbiosis with nodule-inducing rhizobia and arbuscular mycorrhizal (AM) fungi. The existing nodules systemically suppress subsequent nodule formation, a phenomenon known as autoregulation. Grafting experiments revealed that some forms of autoregulation are controlled by the shoot. In the present study, we examined shoot-controlled regulation of AM fungal colonization using a reciprocal grafting technique. Ten-day-old seedlings of wild-type soybean cv. Enrei and its hypernodulating mutant En6500 were cut below the cotyledons and the shoots were grafted to self or reciprocal roots. Grafted seedlings were inoculated with Bradyrhizobium japonicum and Gigaspora rosea and grown in a glasshouse for 60 days. The arbuscule abundance of the En6500 (shoot)/En6500(root) graft was 1.5-fold higher than that of the Enrei/Enrei graft. In grafts between Enrei and En6500, an increased arbuscule abundance was detected only when En6500 was used as the shoot. The arbuscule abundance of Enrei/En6500 when Enrei was used as the shoot was comparable to that of Enrei/Enrei. The intensity of AM fungal colonization was lower in Enrei/En6500 than in the other grafting treatments. From the results obtained, we suggest that soybean shoots systemically control arbuscule formation in both AM symbiosis and nodule formation.     

Soybean (Glycine max [L.] Merr.) shoots systemically control arbuscule formation in mycorrhizal symbiosis

Abstract

The roots of soybean (Glycine max [L.] Merr.) establish symbiosis with nodule-inducing rhizobia and arbuscular mycorrhizal (AM) fungi. The existing nodules systemically suppress subsequent nodule formation, a phenomenon known as autoregulation. Grafting experiments revealed that some forms of autoregulation are controlled by the shoot. In the present study, we examined shoot-controlled regulation of AM fungal colonization using a reciprocal grafting technique. Ten-day-old seedlings of wild-type soybean cv. Enrei and its hypernodulating mutant En6500 were cut below the cotyledons and the shoots were grafted to self or reciprocal roots. Grafted seedlings were inoculated with Bradyrhizobium japonicum and Gigaspora rosea and grown in a glasshouse for 60 days. The arbuscule abundance of the En6500 (shoot)/En6500(root) graft was 1.5-fold higher than that of the Enrei/Enrei graft. In grafts between Enrei and En6500, an increased arbuscule abundance was detected only when En6500 was used as the shoot. The arbuscule abundance of Enrei/En6500 when Enrei was used as the shoot was comparable to that of Enrei/Enrei. The intensity of AM fungal colonization was lower in Enrei/En6500 than in the other grafting treatments. From the results obtained, we suggest that soybean shoots systemically control arbuscule formation in both AM symbiosis and nodule formation.     

Isolation and determination of anthocyanins in seed coats of black soybean (Glycine max (L.) Merr.).

Anthocyanin pigments in seed coats of black soybean (Glycine max (L.) Merr.) were extracted with 1% HCl-CH(3)OH, and the crude anthocyanin extract was purified by Shepadex LH-20 and Lichroprep RP-18 open-column chromatography. Three major anthocyanins were isolated, and their chemical structures were identified by spectroscopic methods (UV-visible, FABMS, (1)H and (13)C NMR, and by TLC). The complete structures of these anthocyanins were elucidated as delphinidin-3-glucoside, cyanidin-3-glucoside, and petunidin-3-glucoside. Among them, petunidin-3-glucoside was identified as a new anthocyanin in black soybeans. On the basis of RP-HPLC with a UV-vis detector, the contents of delphinidin-3-glucoside, cyanidin-3-glucoside, petunidin-3-glucoside, and total anthocyanins in seed coats of 10 black soybeans were found in the ranges of 0-3.71, 0.94-15.98, 0-1.41, and 1.58-20.18 mg/g, respectively. The results obtained in this study imply that the seed coats of black soybean can be used as a good source for cyanidin-3-glucoside and delphinidin-3-glucoside.     

Sulfur uptake by soybeans (Glycine max L.)

Abstract

Sulfur accumulation in young soybean plants tended to follow the pattern reported for P differing only in quantity. Soybean stems tended to have a more constant S concentration over time than did leaves or petioles.

The nutrient uptake pattern of a crop provides clues to more efficient management of plant nutrients. The recent reports of increased yields of soybeans due to foliar fertilization would seem to be a culmination of previous work done in Iowa on nutrient uptake patterns (1, 2, 3).

In the work reported to date there are no data which illustrate patterns of sulfur uptake by soybeans during the growing season. The work reported here was an attempt to determine the pattern of S uptake by soybeans during early growth stages.     

Correlations of oil and protein with isoflavone concentration in soybean [Glycine max (L.) Merr.

Twelve isoflavones were detected by high-performance liquid chromatography in seeds of 17 soybean [Glycine max (L.) Merrill] cultivars grown at three locations. 6' '-O-Malonyldaidzin and 6' '-O-malonylgenistin together constituted 71-81% of total isoflavones, which ranged in concentration from 2038 to 9514 microg/g and averaged 5644 microg/g across locations and cultivars. The total as well as several individual isoflavones had a moderate negative correlation with oil across locations and cultivars. Six cultivars had a moderate or strong negative correlation of total isoflavones with oil. Five cultivars had a moderate or strong positive correlation of total isoflavones with protein. These results suggest that judicious selection of germplasm for soybean breeding may facilitate development of soybean lines with desirable isoflavone concentrations.     

Growth characteristics,phytate contents,and coagulation properties of soymilk from a low-phytate Japanese soybean (Glycine max (L.) Merr.) line

The phytic acid (myo-inositol hexakisphosphate or InsP₆) content of seed crops is important to their nutritional quality. Since it represents 75?±?10% of the total seed phosphorus (P), phytic acid is also important regarding the management of P in agricultural production. A low-phytate F5 line, No. T-2-250-4-20, was selected from the progeny of a cross between the low-phytate soybean line CX1834 and the Japanese commercial cultivar Tanbakuro. This line and its parents were grown in a field nursery, and the growth characteristics, phytate accumulation, and processing suitability for tofu were evaluated. At full maturity, the weight of seeds per plant of line T-2-250-4-20 was 5.2- and 1.3-fold higher than that of CX1834 and Tanbakuro, respectively. The amount of phytate-phosphorus as a percentage of the total P content in seeds was 23% in line T-2-250-4-20-34, 30% in CX1834, and 69% in Tanbakuro. No significant difference was observed among the three cultivars/lines in their seed magnesium (Mg), potassium (K), crude protein, and sugar. However, the calcium (Ca), crude fat and ash contents in seeds of line T-2-250-4-20-34 and Tanbakuro was lowered compared to that of CX1834. The breaking stress of tofu was estimated employing a rheometer with a decreasing concentration of the coagulant magnesium chloride (MgCl₂), starting at 15.7?mmol?L^?1. In tofu made from Tanbakuro, the concentration of MgCl₂ required to achieve the maximum breaking stress was 12.6?mmol?L^?1; however, it was 9.5?mmol?L^?1 for tofu made from T-2-250-4-20-34 and CX1834. The tofu made from Tanbakuro was soft and broke at 6.3?mmol?L^?1 MgCl₂, but, in line T-2-250-4-20-34, harder tofu was made with lower MgCl₂ concentrations. No difference was observed among the cultivars/lines in the SDS-PAGE patterns of protein in soymilk. These results indicate that we have developed a low-phytate soybean with adequate productivity, and confirmed that tofu made from the low-phytate T-2-250-4-20-34 soybean becomes coagulated and harder at a lower MgCl₂ concentration than that from high-phytate soybean cultivars.     

Classification and Characteristic of Maturity Groups of Chinese Landraces of Soybean [Glycine max (L.) Merr.]

To link Chinese soybean classification with the world soybean maturity group system suggested by American researchers, 264 soybean landraces from China and 48 varieties of 13 soybean maturity groups from the United States (US) were tested under the natural and extended day-length at Nanjing, China. Based on comparing Chinese with the US soybeans in days to maturity, Chinese soybean landraces were classified into maturity group (MG) 000, 00, 0, I, II,..., IX, which only MG X might not exist in China. Chinese soybean landraces in each of MG 0, I, II and III revealed large variation in days to flowering and were almost grown in all eco-regions in China. These four maturity groups were further divided into eight sub-groups according to the variation in days to flowering and geographical distribution of soybeans of the same maturity group. The geographic distribution of soybean maturity groups in China was also presented in this paper. This study should be significant for soybean researchers in the world to understand the whole feature of Chinese soybean landraces germplasm.     

Dynamic chloroplast pigments concentration in leaves of soybean ( Glycine max [L.] Merr.) under reduced tillage

The objectives of this experiment were to determine the chloroplast pigments dynamics of soybean leaves during the growth stages under different tillage systems, which can be a major factor limiting yield of soybean. The greatest differences between the photosynthetic productivity parameters of the investigated soybean were determined from reproductive stages (R2 and R3?–?4). The chlorophyll a, chlorophyll a/b and carotenoids content under CT, DH and NT were greater in the reproductive stages (R2 and R3?–?4) than in the early stages (V3?–?4 and R1). The concentration dynamics of chlorophyll b and chlorophyll a/b was very similar in all growth stages and under all tillage systems in the 2-yr average. The increased drought stress in 2003 was likely critical in the observed lower seed yields in 2003. The yield of soybean was significantly lower under NT than CT and DH treatments in both years. The relationship between the soybean yield and chloroplast pigments concentration is strongly influenced by external factors. In the 2-yr average the soybean yield was considerably affected by the years and tillage systems. Statistical analysis showed a very significant relationship between chlorophyll pigments content, but photosynthetic parameters investigated did not correlate with soybean yield.     

Rapid and reversible nitrate inhibition of nodule growth and N2 fixation activity in soybean (Glycine max (L.) Merr.)

Nodulated soybean (Glycine max. (L) Merr. cv. Williams) plants were hydroponically cultured, and various combinations of 1-week culture with 5 or 0 mm nitrate were applied using 13-d-old soybean seedlings during three successive weeks. The treatments were designated as 0-0-0, 5-5-5, 5-5-0, 5-0-0, 5-0-5, 0-5-5, and 0-0-5, where the three sequential numbers denote the nitrate concentration (mm) applied in the first-second-third weeks. The size of the individual nodule was measured periodically using a slide caliper. All the plants were harvested after measurement of the acetylene reduction activity (ARA) at the end of the treatments. In the 0-0-0 treatment, the nodules grew continuously during the treatment period. Individual nodule growth was immediately suppressed after 5 mm nitrate supply. However, the nodule growth rapidly recovered by changing the 5 mm nitrate solution to a 0 mm nitrate solution in the 5-0-0 and 5-5-0 treatments. In the 5-0-5 treatment, nodule growth was completely inhibited in the first and the third weeks with 5 mm nitrate, but the nodule growth was enhanced in the second week with 0 mm nitrate. The nodule growth response to 5 mm nitrate was similar between small and large size nodules. After the 5-5-5, 5-0-5, 0-0-5, and 0-5-5 treatments, where the plants were cultured with 5 mm nitrate in the last third week, the ARA per plant was significantly lower compared with the 0-0-0 treatment. On the other hand, the ARA after the 5-0-0 and 5-5-0 treatments was relatively higher than that after the 0-0-0 treatment, possibly due to the higher photosynthate supply associated with the vigorous vegetative growth of the plants supplemented with nitrate nitrogen. It is concluded that both soybean nodule growth and N₂ fixation activity sensitively responded to the external nitrate level, and that these parameters were reversibly regulated by the current status of nitrate in the culture solution, possibly through sensing of the nitrate concentration in roots and / or nodules.     

Genetic diversity and population structure of vegetable soybean (Glycine max (L.) Merr.) in China as revealed by SSR markers

Vegetable soybean is a kind of value-added specialty soybean serving as vegetable or snacks. Understanding the genetic structure of vegetable soybean is a key point for further utilization in breeding programs. In the present study, the genetic structure and diversity of 100 vegetable soybean accessions planted in China was analyzed using 53 simple sequence repeat (SSR) markers. A total of 296 alleles were detected with an average of 5.6 alleles per SSR locus. The polymorphism information content (PIC) values of SSR markers ranged from 0.074 to 0.831, with an average of 0.573. Nei’s genetic distance between accessions ranged from 0 to 0.9434 with an average of 0.6286. These vegetable soybean germplasms could be divided into 8 subgroups based on STRUCTURE analysis, or 11 subgroups based on unweighted pair group method with arithmetic average (UPGMA) cluster. Further comparison showed that the UPGMA subgroups and STRUCTURE subgroups were in fact highly consistent. Germplasms in each classified groups showed great consistency with their origins, seed coat colors or pedigrees. Genetic relationships among germplasm panels that initially came from different geographical regions were also analyzed. Germplasm panels from China Mainland, Taiwan Island and Japan were highly similar to each other with the similarities of over 98 %. Molecular data and cluster analysis also showed that germplasms from China Mainland are more diverse than those from other areas. These results gave us a deep insight into the genetic structure of vegetable soybeans in China and will help us to improve the breeding strategies.     

Variation of nitrogen accumulation and yield in response to phosphorus nutrition of soybean (Glycine max L. Merr.)

Phosphorus (P) is essential macronutrient for soybean [Glycine max (L.) Merr.] growth and function. The objective of this study was to determine effect of phosphorus nutrition (including phosphorus nutrition level and interruption of phosphorus supply) on nitrogen accumulation, nodule nitrogen fixation and yield of soybean plants by ¹⁵N labeling with sand culture. The results showed that they all presented a single peak curve with improvement of phosphorus nutrition level, when phosphorus concentration of nutrient solution was about 31 mg/L, they all reached the maximum and effect of phosphorus nutrition level on nodule nitrogen fixation was lower than that on yield formation level. Interruption of phosphorus supply during soybean growth period, nitrogen accumulation and nodule nitrogen fixation were seriously inhibited, and yield was decreased significantly when interruption of phosphorus supply during V₃-R₁ and R₁-R₅ period, while interruption of phosphorus supply during R₅-R₇ period had no significant effect on nitrogen accumulation, nodule nitrogen fixation and yield. So soybean nitrogen metabolism and yield were sensitive to phosphorus nutrition in the V₃-R₅ period, those were not sensitive to phosphorus nutrition after R₅ period.