Seed Ca Concentration Research Articles

Uptake and timing of calcium in runner peanut (Arachis hypogaea L.)

Peanut production in the southeastern United States is often limited due to low Ca availability. Gypsum and lime are common Ca supplements for peanut, but the indeterminate nature of peanut and variable solubility of these products adds uncertainty to timing of Ca amendments. Two sets of field trials were performed in southern Alabama from 2012 to 2014 under both irrigated and non-irrigated conditions using two runner-type peanut cultivars (Georgia-06G and Georgia Greener) to determine Ca uptake patterns and timing of amendments. Calcium uptake was evaluated by pod development stage with four soil Ca treatments: 560 and 1120 kg ha −1 gypsum applied at early bloom, 1120 kg ha −1 lime at planting, and an untreated control. Developmental stages were determined by the hull scrape method. The timing of gypsum and lime was evaluated using metrics of peanut yield, grade, germination, and seed Ca. Treatments included a single application of gypsum at planting and early bloom, split applications of gypsum at planting/early bloom and early/mid-bloom, lime at planting, lime at planting plus gypsum at early bloom, and an untreated control. Results suggested that peanut absorbed Ca throughout the entire growing season and that seed Ca concentration could be used as an indicator of early-season seed quality. Split applications of gypsum at early/mid-bloom tended to have a superior performance than a single application at planting or early bloom and split applications at planting/early bloom. Supplemental gypsum at early bloom combined with lime at planting further increased Ca availability under non-irrigated conditions relative to the lime-only treatment. This study provided helpful information for Ca nutrient management for peanut.

Effect of Gypsum Application Rate, Soil Type, and Soil Calcium on Yield, Grade and Seed Quality of Runner Type Peanut Cultivars

ABSTRACT Calcium (Ca) availability in the 0 to 8 cm soil depth often limits peanut yield and influences grade in the southeastern United States. Field experiments were conducted in 2012 and 2013 at the University of Georgia's Coastal Plain Experiment Station, Tifton, GA (CPES) and the Southwest Georgia Research and Education Center, Plains, GA (SWREC) to determine large-seeded (Georgia-06G) and medium-seed sized (Georgia Greener) runner-type cultivar response to gypsum application rates of 0, 560, 1120, 1650 kg/ha. Peanut pod yield and grade (TSMK) were significantly different between locations with 7610 and 6540 kg/ha at CPES and SWREC, respectively. However, there were no differences between peanut cultivars or gypsum rates. Standard germination, seed vigor (cold germination), and seed Ca content analysis were also conducted on subsamples from each plot. Average peanut seed germination was 97% across all samples. No differences were observed for standard germination or vigor testing. Differences in locations were observed for yield, TSMK, percent jumbo, percent medium kernels, and seed Ca content. Peanut cultivar and gypsum application rate had effects on seed Ca concentration. Seed Ca concentration levels were 825 and 787 mg/kg for Georgia Greener and Georgia-06G, respectively. Seed Ca content increased as field gypsum application rate increased at both locations.

Soil Evaluation Methods for Calcium for Peanut (Arachis hypogaea L.) Production in the Coastal Plain

ABSTRACT Successful peanut production requires adequate Ca in the pegging zone. Soil testing for Ca based on pegging zone samples provides scientific basis for Ca supplementation for peanut, but concerns regarding inaccuracy of certain soil testing methods have been brought up by previous studies; therefore, reevaluation of routine soil testing methods for Ca on pegging zone samples is necessary. The objective of this study was to evaluate relationships and predictability of four major soil tests including Mehlich 1 (M1), Mehlich 3 (M3), 1 N neutral ammonium acetate (AA), and 0.01 M sodium nitrate (SN) for Ca, K, and Mg for peanut production in Coastal Plain soils common in the major peanut producing regions of the Southeast. Results showed that the four tests extracted varied amount of Ca, K, and Mg from soil. Soil treatments that included an addition of gypsum or lime reduced availability of soil K and Mg. Correlations were strong among soil K and Mg determined using M1 and M3, but the relationship was weak between M1 and SN. Application of gypsum shortly before soil sampling had minimal effect on correlations among the four tests; however, application of lime led to weaker correlations. In unamended or gypsum-treated soils, M1 is an adequate index of soil available Ca for peanut. The M1 test may overestimate soil available Ca if soil is recently limed; therefore, any of the other three soil tests may be used in such cases. The AA test for Ca had the best relationships to peanut yield, grade, and seed Ca concentration, followed by M1.

Genotypic Variability in Calcium Concentration of Peanut (Arachis hypogaea L.) Seeds

ABSTRACTLeaf spots are devastating diseases of peanut worldwide. The University of Florida peanut (Arachis hypogaea L.) breeding program has developed cultivars with superior resistance to leaf spot diseases, but their production was limited by poor field emergence. One factor that is believed to be related to emergence of resistant cultivars is reduced accumulation of seed Ca. The goal of this study was to compare the seed Ca concentrations of resistant genotypes to susceptible genotypes and to assess the genetic variability for seed Ca accumulation in commercial peanut germplasm. Seed Ca concentrations were measured for 51 genotypes that were diverse for market class, maturity, resistance to leaf spot, and genetic background. Genotypes were placed into categories based on seed size and maturity: Large seeded genotypes (“Virginias”), small seeded with medium maturity (“Medium”), and small seeded, late maturing (“Late”) which contained the resistant genotypes. For each of these groups, the seed Ca concentration was calculated and heritability of Ca concentration was determined for each group. Late maturing runners (those with the highest resistance to leaf spot) had the lowest seed Ca concentration followed by the medium maturing runners, and then the large seeded Virginias. The broad‐sense heritability estimate for seed Ca concentration was 0.33 and estimates were 0.26, 0.19, 0.41 for the Late, Medium, and Virginia groups, respectively. These results suggest that seed Ca concentration can be improved through breeding, which may allow for the development of cultivars with leaf spot resistance and commercially acceptable seed vigor.

Effect of Cultivar, Irrigation, and Soil Calcium on Runner Peanut Response to Gypsum

Calcium is often limiting to peanut (Arachis hypogaea L.) yield, grade, and germination in the southeastern United States. The response of large‐seeded (Georgia‐06G) and small‐seeded (Georgia Green) runner peanuts to gypsum applications was evaluated in 14 tests in southern Alabama and Georgia. Experiments were conducted in a randomized complete block design with four replications of gypsum applications as main treatments (0, 560, 1120, and 1680 kg ha−1) in soils with a range of soil Ca (178–498 mg kg−1) in both irrigated and non‐irrigated tests. Increases in yield, grade, seed Ca, and germination were significant with increased gypsum application for non‐irrigated tests when data were combined. In the non‐irrigated tests, yield increases ranged from 500 to 1000 kg ha−1 and grade indicated by sound mature kernels (SMK) increased 3.4 to 5%. Critical pegging zone soil Ca values of 150 and 250 mg kg−1 were evaluated and found appropriate for irrigated and non‐irrigated peanuts, respectively. Georgia‐06G had lower seed Ca concentrations and slightly lower germination than Georgia Green. More than 95% germination of Georgia‐06G and Georgia Green was observed when seed Ca concentrations were >600 mg kg−1. Analysis of Ca concentrations in nearly mature seeds pre‐harvest may provide an indication of seed germination quality as seed Ca concentration increased at approximately the same rate as seed size from immature white to mature black peanut maturity classes using the hull‐scrape method.

Variation in Response to Calcium Fertilization among Four Runner‐Type Peanut Cultivars

Seed quality of peanut (Arachis hypogaea L.) is influenced by seed Ca concentration, which is known to be affected by seed size and soil Ca fertility during seed production. Little is known about soil Ca requirements for large‐seeded runner‐type cultivars or for late maturing peanut cultivars that display poor seed quality. This study was conducted to determine if excess Ca fertilization during seed production would improve the laboratory germination and/or seedling emergence of large‐seeded runner‐type peanut cultivars (‘C‐99R’ and ‘AP‐3’) and late‐maturing runner‐types (‘DP‐1’ and C‐99R). Trials were conducted near Marianna, FL, in 2005, 2006, and 2007 using four cultivars and four gypsum treatments (0, 784, 1568, and 2352 kg ha−1) to provide excess soil Ca. Pretreatment soil extractable (Mehlich‐1) Ca was 589 kg ha−1 in 2005, 811 kg ha−1 in 2006, and 848 kg ha−1 in 2007, all of which are above the recommended level. The cultivar average seed size (g/100 seeds) ranking was C‐99R > AP‐3 > DP‐1 > ‘Georgia Green’, whereas average seed Ca concentration (mg kg−1) ranked Georgia Green > AP‐3 = C‐99R > DP‐1. Cultivar seedling emergence ranking was Georgia Green = AP‐3 > C‐99R > DP‐1 and germination ranked Georgia Green = AP‐3 > C‐99R = DP‐1. These results suggest that the relatively poor emergence of DP‐1 may be, in part, related to its relatively low absorption of seed Ca during seed production. Emergence of C‐99R increased as Ca fertilization increased in 2005, but not in 2006 or 2007. These results suggest that seedling emergence of some large‐seeded cultivars, like C‐99R, may require greater gypsum fertilization if soil Ca levels are marginal during seed production.

Calcium Nutrition of Peanut Grown in Solution Culture. II. Pod-zone and Tissue Calcium Requirements for Fruiting of a Virginia and a Spanish Peanut

ABSTRACT Virginia peanut types need more calcium (Ca) in the soil than Spanish types for high pod yield, but their actual soil solution and fruit tissue Ca requirements have not been well defined. A split root and pod solution culture technique was used to examine the effects of Ca concentration on fruiting of one Virginia cv. ‘Virginia Bunch 1’ and one Spanish peanut cv. ‘TMV-2’. Plants were grown in complete nutrient solution (root zone) containing 100 μM Ca, and six treatments imposed in which the pod zone solution Ca was controlled at 0 to 2500 μM. ‘TMV-2’ produced some mature seeds with no Ca added to the pod zone solution and 81% of maximum seed dry matter at 5 μM Ca, a concentration at which its pod dry matter production was close to maximum. In contrast, ‘Virginia Bunch 1’ produced no pods with no Ca added to the pod zone and only 28% of maximum pod dry matter at 5 μM Ca. ‘TMV-2’ required 6 and 21 μM Ca in the pod zone solution for 95% of maximum pod and seed production, respectively. The corresponding solution concentrations for ‘Virginia Bunch 1’ were 35 and 50 μM Ca. The seed dry matter production of ‘Virginia Bunch 1’ decreased with ≥112 μM Ca in the pod zone solution due to a decrease in individual seed mass, but there was no depression in the case of ‘TMV-2’ up to the highest pod zone solution concentration of 2500 μM Ca studied. The Ca concentration in pod walls and seeds of both cultivars increased with increase in Ca up to 500 μM in the pod zone, the effect being greater in ‘TMV-2’. However, the seed production of both cultivars was maximized at approximately the same seed Ca concentration of 0.04%. The results of this study have shown that the Spanish peanut cv. ‘TMV-2’ and the Virginia peanut cv. ‘Virginia Bunch 1’ have a similar tissue Ca requirement for seed growth despite the higher pod zone Ca requirement of ‘Virginia Bunch 1’.

Contrasting accumulations of calcium and magnesium in seed coats and embryos of common bean and soybean

How plant genotypes affect accumulation and within-seed distribution of Ca and Mg in soybean ( Glycine max L.) and common bean ( Phaseolus vulgaris L.) seed is important because of concerns in regards to human nutrition. Accumulation of seed Ca and Mg in separate experiments, each with 12 genotypes, was studied. Genotype affected seed Mg concentration [Mg] and especially seed Ca concentration [Ca] in the two species. Percentages of total seed Ca in seed coats ranged from 67% to 81% for the common bean genotypes and from 17% to 27% for the soybean genotypes. Percentages of total seed Mg in the seed coats ranged from 16% to 28% for the common bean genotypes and from 6% to 10% for the soybean genotypes. Percentages of seed dry matter in the seed coats were 9.3–11.0% for the common bean genotypes and 7.0–12.4% for the soybean genotypes. Four common bean and two soybean genotypes were next grown under similar environmental conditions in a greenhouse experiment. Results confirmed that seed coats of common bean are enriched in Mg and especially Ca relative to dry-matter distribution. In contrast, seed coats of soybean are enriched in Ca, but to a lesser extent than in common bean, and are not enriched in Mg.

Genetic control of seed weight and calcium concentration in chickpea seed

Chickpea, Cicer arietinum L., is a staple protein source in many Asian and Middle Eastern countries. Hence, the mineral content of its seed, especially that of calcium, is of nutritional importance. Calcium is transported through plants and to legume pods almost exclusively via the xylem stream, with Ca accretion in developing seeds resulting primarily from diffusion of Ca from the adjoining pod wall. Thus, for seeds of differing surface-to-mass ratios, Ca concentration is expected to correlate inversely with seed weight. The relationship between seed weight and Ca concentration in chickpea seeds was studied using a range of germplasm and derivatives from crosses between types differing in seed Ca concentration. Among the cultivars tested, low seed mass was associated with high Ca concentration. However, the study of hybrid progeny indicated that seed Ca content was mainly determined by genetic factors other than grain weight genes. This finding may assist in future breeding of high nutritional quality chickpea cultivars.

Calcium Effects on Soybean Seed Production, Elemental Concentration, and Seed Quality

Soybean [Glycine max (L.) Merr.] plants produce fewer and lower quality seeds when grown in conditions that decrease seed Ca concentration. Indeterminate soybean was grown in modified hydroponic culture to ascertain the effects of Ca deficiency on leaf dry matter, seed production and elemental concentration, and the effect of pod position on seed elemental concentration in 1992 and 1993. Treatments consisted of 2.0 (Control), 0.2 (Low), 0.1 (Very Low) mM Ca in the nutrient media. Some Control plants were switched to Low or Very Low (Con/L, VL) Ca levels at beginning seed growth stage (R5), and some plants grown at the Very Low Ca level were switched to the Control (VL/Con) Ca level at R5. At harvest, plants were divided into four sections: top‐third (T/3), middle‐third (M/3), and bottom‐third (B/3) of the mainstem and branches (Br). Low and Very Low treatments produced 65 and 10% as much seed mass, respectively, as Control in both years. Low and Very Low treatments retained significantly less total leaf dry matter at R5 in both years. Seed Ca levels were 25 to 300% higher in treatments that included the Control Ca level during any part of reproductive growth compared to other treatments in both years. Seed Ca concentration was highest in the T/3 and Br sections in both years. Germination was reduced in treatments not including the Control solution during part of the reproductive growth period in both years. Decreased Ca levels in the nutrient medium reduced soybean leaf dry matter during seed fill, seed production, seed Ca concentration, and seed germination, and increased the incidence of seedling disorders such as watery hypocotyl and epicotyl necrosis.

Accumulation of Calcium in Bean Cultivars Differing in Seed Size

Accumulation of Ca, Mg and K, the principal cations in dry bean (Phaseolus vulgaris L) seed, was studied under field and greenhouse conditions. ‘Cran-09’, a cranberry bean and ‘Norstar’, a navy bean, were grown to maturity under greenhouse conditions. ‘Cran-09’ had a seed weight of 605 mg, a seed Ca concentration of 1·2 g kg-1 and a Ca harvest index of 0·032. The corresponding three parameters in ‘Norstar’ were a seed weight of 161 mg, a seed Ca concentration of 2·2 g kg-1 and a Ca harvest index of 0·064. The difference in seed Ca concentration was not due to increased absorption of Ca by ‘Norstar’, but rather was due to a larger proportion of Ca in plant tops being diverted to the seed component. The larger seed Ca concentration in ‘Norstar’ was compensated to some extent by a smaller seed K concentration. In contrast to Ca, cultivar had relatively little effect on harvest indices for Mg, K, N and P. The average seed Ca concentration in six navy bean cultivars grown under field conditions was 90% more than that of three kidney and three cranberry bean cultivars. © 1997 SCI.

Accumulation of Calcium in Bean Cultivars Differing in Seed Size

Accumulation of Ca, Mg and K, the principal cations in dry bean (Phaseolus vulgaris L) seed, was studied under field and greenhouse conditions. ‘Cran-09’, a cranberry bean and ‘Norstar’, a navy bean, were grown to maturity under greenhouse conditions. ‘Cran-09’ had a seed weight of 605 mg, a seed Ca concentration of 1·2 g kg-1 and a Ca harvest index of 0·032. The corresponding three parameters in ‘Norstar’ were a seed weight of 161 mg, a seed Ca concentration of 2·2 g kg-1 and a Ca harvest index of 0·064. The difference in seed Ca concentration was not due to increased absorption of Ca by ‘Norstar’, but rather was due to a larger proportion of Ca in plant tops being diverted to the seed component. The larger seed Ca concentration in ‘Norstar’ was compensated to some extent by a smaller seed K concentration. In contrast to Ca, cultivar had relatively little effect on harvest indices for Mg, K, N and P. The average seed Ca concentration in six navy bean cultivars grown under field conditions was 90% more than that of three kidney and three cranberry bean cultivars. © 1997 SCI.

Aiuminium tolerance of durum wheat germplasm

Aluminium tolerance of Macedonian durum wheat (Triticum turgidum L. conv. durum (Desf.) MacKey) germplasm was evaluated in nutrient solutions containing 0, 74 or 148 μM of total Al. Relative root length (148 μM Al/0 Al) of various genotypes ranged from 41 to 72% (from moderately sensitive to moderately tolerant to Al). No genotype with Al tolerance close to that of very tolerant T. aestivum cultivar Atlas-66 was found. Seed Ca concentration was positively (r=0.64, P≤0.05) and seed Fe concentration negatively (r=−0.71, P≤0.05) related to the relative root growth. Such a significant correlation was not obtained for seed concentrations of other nutrients or seed protein content.

Calcium and Relative Humidity Effects on Soybean Seed Nutrition and Seed Quality

Reduced seed calcium concentrations have been observed in soybean [Glycine max (L.) Merr.] seed lots with reduced seed germination. Soybean plants were grown hydroponically at Ames, IA, 1991, to determine if the Ca concentration of the root medium and relative humidity (RII) could influence seed Ca concentration and, subsequently, seed quality. Plants were grown in solution culture in a controlled environment growth chamber, with Ca concentrations of 0, 0.6, 1.2, and 2.5 mM in the root medium from beginning seed (R5) to beginning maturity (R7). In addition, concentrations of 0.6 and 2.5 mM Ca and RH of 55 and 95% were applied from R5 to R7 to plants grown in sand culture in the greenhouse. Treatments were arranged in a randomized compete‐block design in both studies, with the blocks replicated in time in the growth‐chamber study. Seed Ca concentrations increased with increased Ca supply to the plant. Relative humidity had not effect on either seed Ca concentration or germination. A decrease in the percentage of normal seedlings from 96.7 to 41.8% coincided with a decrease in seed Ca from 2.37 to 0.87 mg g−1. Reduced germination of low‐Ca seeds was primarily due to an increase in the percentage of abnormal seedlings. The percentage of normal seedlings was significantly and positively correlated with Ca (r = 0.83) and negatively correlated with the B/Ca ratio and B (r = ‐0.97 and −0.83, respectively) in seeds. Results indicate that reduced Ca supply to the plant may reduce seed Ca concentration in addition to altering other seed nutrients. Reduced seed Ca was associated with poorer seed germination, but additional studies are needed to clarify the role of Ca and other nutrients in the germination of seeds and seedling establishment.

Seed quality of runner peanuts as affected by gypsum and soil calcium1

Abstract There is only weak evidence that supplemental soil Ca may be beneficial beyond its obvious effects on yield and sound mature kernel (SMK) of runner peanuts (Arachis hypogea L.). This study was initiated to determine the effect of applied Ca on seed Ca, seed germination, and seedling vigor on sites varying in extractable soil Ca and to determine the minimum seedCa concentration required for maximum germination and seedling vigor of runner peanuts. Eight on‐farm experiments with replicated gypsum and no‐gypsum treatments were established on soils with 130 to 625 mg/kg Melich‐1 extractable Ca. Yield and SMK were generally unaffected by the gypsum topdressing, but there were effects on seed concentrations of Ca, Mg, and K. One site showed a highly significant increase in germination and seedling vigor from the gypsum application and two other sites had a significant increase in seedling survival without a simultaneous increase in germination. The minimum seed Ca needed for maximum germination was 282 mg/kg, while the minimum needed for maximum seedling survival was 260 mg/kg. The data suggest that a higher level of available soil Ca is needed for maximum seed quality than is needed to obtain maximum yield or SMK.

Calcium Content, Adenylate Energy Level, and Seed Vigor in Peanuts1

Germination disorders and seed calcium deficiency are frequently associated in Virginia peanut (Arachis hypogaea L.) cultivars, while neither condition is common in Spanish peanuts. Embryonic Ca concentration was compared with (a) germination percentage after 3 days of cold treatment and (b) total adenylate pool in the embryonic axis after 12 hours of germination in the parents and F3 embryos of a Virginia ✕ Spanish cross. Ca concentration was found to be positively correlated with germination percentage and total adenylates for plants of the Virginia parent and the cross but not for the Spanish parent. Means for the percent cold germination, Ca concentration and total adenosine phosphates were at least 85% greater for the Spanish than for the Virginia parent. High means for adenylate concentration and percent cold germination for the F3 progeny suggested that the genetic variance for these traits was nonadditive, while intermediate Ca values for the progeny suggested that additive genetic variance was important in the inheritance of seed Ca concentration. The adenylate assay correlated with differences in seed vigor among the parents and F3 progeny but was less sensitive than Ca concentration in detecting differences within populations. Energy charge (E.C.) values calculated from adenylate data according to the formula E.C. = [(ATP) + 1/2 (ADP)]/[(ATP) + (ADP) + (AMP)] were not significantly correlated with germination percentage, implying that respiratory phosphorylation rate in early germination was not as limiting as other factors in peanut seed germination. High broad‐sense heritability estimates for Ca concentration (H = 0.68), percent cold germination (H = 0.74) and total adenylates (H = 0.88) suggest that seed quality as related to the above parameters can be improved through breeding.