C. D. Foy

Tolerance of soybean germplasm to an acid Tatum subsoil

Abstract Aluminum tolerant soybean cultivars are needed for deeper rooting and increased drought tolerance in acid subsoils. Fifteen cultivars or plant introductions were screened for Al tolerance by growing them for 33 days in pots of unlimed (pH 4.3) and limed (pH 5.6) Taturn subsoil. Tolerance was based upon plant symptoms on unlimed soil (leaf cupping, chlorosis or necrosis, and petiole collapse), absolute dry‐weights of shoots and roots on unlimed soil and relative (unlimed/limed %) shoot and root weights. On unlimed soil, absolute dry weights ranged 4‐fold for shoots and 7‐fold for roots. Relative weights (unlimed/limed %) ranged 2.7‐fold for shoots and 6‐fold for roots. Based on these criteria, entries PI248511 (Japan), Perry (USA), PI381674 (Uganda), Amcor (Ohio USA) and Hernon 147 (Zimbabwe, Africa) were judged most tolerant to the acid soil. Most sensitive entries included Sable, Oribi and Duiker, all from Zimbabwe, Africa, and Chief (USA). Santa Rosa (Brazil) was only moderately tolerant. Entri...

Tolerance of barley cultivars to an acid, aluminum‐toxic subsoil related to mineral element concentrations in their shoots

Abstract Barley, Hordeum vulgare L., is extremely sensitive to excess soluble or exchangeable aluminum (Al) in acid soils having pH values below about 5.5. Aluminum tolerant cultivars are needed for use in rotations with potatoes which require a soil pH below 5.5 for control of scab disease. They are also potentially useful in the currently popular “low input, sustainable agriculture (LISA)”; in which liming even the plow layer of soil is not always possible or cost effective, or in situations where surface soils are limed but subsoils are acidic and Al toxic to roots. Ten barley cultivars were screened for Al tolerance by growing them for 25 days in greenhouse pots of acid, Al‐toxic Tatum subsoil (clayey, mixed, thermic, typic Hapludult) treated with either 750 or 4000 μg•g‐1 CaCO3 to produce final soil pH values of 4.4 and 5.7, respectively. Based on relative shoot dry weight (weight at pH 4.4/weight at pH 5.7 X 100), Tennessee Winter 52, Volla (England), Dayton and Herta (Denmark) were significantly mo...

Differential manganese tolerances of cotton genotypes in nutrient solution

Abstract Cotton genotypes [Gossypium hirsutum (L.)] C‐310–73,‐307 (307) and C‐Sgl, 70–517 (517), shown previously to differ in tolerance to an acid (pH 5.1), high manganese (Mn) Grenada soil from Arkansas, were grown in nutrient solutions containing variable concentrations of excess Mn to confirm and characterize their postulated differences in Mn tolerance. Based on crinkle leaf symptoms and leaf dry weights, the 307 genotype was significantly more tolerant than 517 to 4, 8, or 16 mg Mn/L at a maintained pH of 4.6 (Experiment 1) and also to 4 or 8 mg Mn/L at an initial pH of 5.0, not subsequently adjusted (Experiment 2). In Experiment 1, the relative leaf dry weight (wt. with no Mn/wt. with 8 mg Mn/L × 100) was 94% for genotype 307 and only 27% for 517. In Experiment 2, the corresponding relative leaf weights were 75% and 26% for 307 and 517, respectively. Plant analytical results indicated that the 307 genotype tolerates a higher concentration of Mn in its leaves than does 517. This failure to correlate...

Tolerance of sorghum genotypes to an acid, aluminum toxic Tatum subsoil

Abstract Aluminum (Al) tolerant sorghum (Sorghum bicolor L. Moench) genotypes are needed for use on strongly acidic, infertile soils of the tropics and subtropics, where the crop is often grown in a low input, subsistence type of agriculture. Eleven genotypes were first screened for Al tolerance in greenhouse pots of acid, Al‐toxic Tatum subsoil (clayey, mixed, thermic, Typic Hapludult) at pH 4.3 and 5.3. In two subseguent experiments, four genotypes showing wide differences in acid soil tolerance in the first test were grown over pH ranges of 4.3 to 6.4 and 4.7 to 7.0. Acid soil tolerance was determined by absolute dry shoot and root weights at low pH and relative (low pH/high pH %) shoot and root weights. Genotypes differed by as much as 10 fold in relative shoot weight and 8 fold in relative root weight. Genotypic tolerances to acid, Al toxic Tatum subsoil were in good agreement with those obtained on acid field sites in Georgia and Brazil. Hence, results indicated that Al toxicity is a major selection...

Correlation of shoot and root growth and its role in selecting for aluminum tolerance in soybean

Abstract Aluminum‐tolerant soybean cultivars are needed for deeper rooting and increased drought tolerance in acid subsoils. A major limitation in the development of such cultivars is Al‐screening methodology. Shoot growth is often used to infer root growth, but the genotypic relationships between root and shoot growth of older soybean plants have not been evaluated. Our objectives were (i) to test the hypothesis that shoot growth is a reliable indicator of acid soil (Al) tolerance in soybean, and (ii) to determine the relative Al tolerances of selected soybean genotypes. Nine genotypes were evaluated for Al tolerance by growing them for 37 days in greenhouse pots of unlimed (pH 4.3) and limed (pH 5.3) Tatum subsoil. Aluminum tolerance was determined by root and shoot growth and plant symptoms. Aluminum tolerance was detected using both shoot and root growth, and agreement between these two selection criteria was good. Genotypic correlations between root and shoot growth for unlimed soil, for limed soil, ...

Tolerance of durum wheat lines to an acid, aluminum‐toxic subsoil

Abstract Durum wheat, Triticum durum Desf., is reportedly more sensitive to aluminum (Al) toxicity in acid soils than hexaploid wheat, Triticum aestivum L. em. Thell. Aluminum‐tolerant genotypes would permit more widespread use of this species where it is desired, but not grown, because of acid soil constraints. Durum wheat germplasm has not been adequately screened for acid soil (Al) tolerance. Fifteen lines of durum wheat were grown for 28 days in greenhouse pots of acid, Al‐toxic Tatum subsoil at pH 4.5, and non‐toxic soil at pH 6.0. Aluminum‐tolerant Atlas 66 and sensitive Scout 66 hexaploid wheats were also included as standards. Based on relative shoot and root dry weight (wt. at pH 4.5/wt. at pH 6.0 X 100), durum entries differed significantly in tolerance to the acid soil. Relative shoot dry weight alone was an acceptable indicator of acid soil tolerance. Relative dry weights ranged from 55.1 to 15.5% for shoots and from 107 to 15.8% for roots. Durum lines PI 195726 (Ethiopia) and PI 193922 (Brazi...

Acid soil tolerances of wheat lines selected for high grain protein content

Abstract Literature suggests that nitrogen (N) metabolism is involved in differential acid soil (Al) tolerances among wheat (Triticwn aestivum L. en Thell) genotypes. Atlas 66 wheat is characterized by acid soil and aluminum (Al) tolerance, nitrate (NO3 ‐) preference, pH increase of the rhizosphere, high nitrate reductase activity, and high protein in the grain. Atlas 66 has been used as a high protein gene donor in the development of new high protein wheat lines at Lincoln, NE. The objective of our study was to determine the acid soil tolerances of such lines and to relate such tolerances to their abilities to accumulate grain protein when grown on near‐neutral, non‐toxic soils. Twenty‐five experimental lines, nine cultivars not previously classified as Al‐tolerant or ‐sensitive and three cultivars previously classified according to acid soil tolerance, were grown for 28 days in greenhouse pots of acid, Al‐toxic Tatum subsoil. Relative shoot dry weight (pH 4.35/pH 5.41%) varied from 83.2% for Atlas 66 to...

Tolerances of wheat germplasm to acid subsoil

Abstract Aluminum toxicity is a major growth limiting factor for plants in many acid soils of the world. Correcting the problem by conventional liming is not always economically feasible, particularly in subsoils. Aluminum tolerant plants provide an alternative and long‐term supplemental solution to the problem. The genetic approach requires the identification of Al tolerance sources that can be transferred to cultivars already having desirable traits. Thirty‐five cultivars and experimental lines of wheat (Triticum aestivum L. em. Thell) were screened for Al tolerance on acid Tatum soil (clayey, mixed thermic, typic Hapludult) receiving either 0 or 3500 mg CaCO3/kg (pH 4.1 vs. pH 7.1). Entries showed a wide range of tolerance to the acid soil. On unlimed soil at pH 4.3, absolute shoot dry weights differed by 5‐fold, absolute root dry weights by 6.5‐fold, relative shoot weights (wt. at pH 4.3/wt. at pH 7.1 %) by 4.7‐fold and relative root dry weights by 7‐fold. Superior acid soil (Al) tolerance of ‘BH‐1146...

Differential responses of alfalfa cultivars to aluminum stress

Abstract Toxic levels of aluminum can cause severe yield reduction in alfalfa (Medicago sativa L.), especially in the presence of drought stress. Reactions to Al stress of alfalfa cultivars and germplasms, representing a broad genetic base and the entire range of dormancy types, were evaluated in a Monmouth soil study [26.2% Al saturation (pH 4.8) vs 2.8% Al saturation (pH 5.7)] and in two nutrient solution experiments (0 vs 111 μmol Al; pH 4.5). The soil study, Experiment 1, and Experiment 2 were harvested 28, 40, and 25 d after seeding, respectively. In all studies, entries differed significantly in vigor and yields were reduced significantly by Al stress. In the soil study, only ‘Lahontan’ was not affected significantly by Al stress, although Lahontan, ‘Atlantic’, ‘B13‐A14’ (tolerant check), ‘Ladak 65’, and ‘Mesa‐Slrsa’ had comparable relative weights (dry weight stressed/dry weight unstressed). There were no statistically significant differential responses to Al stress in Experiment 1, however the rel...

Acid soil tolerance of soybean (Glycine Max L. Merr.) germplasm from the USSR

Abstract Nineteen soybean genotypes (ten from the former USSR, two from Brazil and seven from USA) were tested for aluminum (Al) tolerance by growing them for 21 days in greenhouse pots of acid, Al‐toxic, unlimed Tatum (Typic Hapludult) subsoil at pH 4.0 and in limed subsoil at pH 5.1. Aluminum tolerance ranking depended upon the plant traits used in the screening process. Based on absolute dry shoot weights at pH 4.0, Giessener, Brunatna, and St.‐59 (USSR), and Biloxi (USA) were most tolerant; least tolerant entries included Yantarnaya and Smena (USSR), and Davis (USA). Based on relative shoot dry weights (pH 4.0/pH 5.1 %), Giessener, Brunatna, and St.‐59 (USSR) were among the most tolerant, Bossier, Biloxi, Essex, and Perry were intermediate, and Salute 216 (USSR), Chief (USA), and Santa Rosa and IAC‐9 (Brazil) were more sensitive to the acid soil. Based on absolute root dry weights, Giessener, and St.‐59 (USSR), and Biloxi (USA) were among the most tolerant and Smena, Yantarnaya and Salute 216 (USSR), ...