Iron chlorosis in silver maple (Acer saccharum)

1978 Summer.Covers not scanned.Includes bibliographical references.Correctives for iron chlorosis have been applied to soil, sprayed on leaves and injected into woody plants. Some success in woody plants has been achieved from soil applied chelated Fe and injected Fe chelates. Silver maple has been unusual in that little response to chelated Fe was found. Experiments were devised to inject silver maples with different Fe chelate formulations, comparing results with a soil applied EDDHA treatment as well as chlorotic and green controls. Silver maple, for the most part, failed to respond to any of the chelate treatments applied. Foliar analyses revealed high levels of foliar Ca in chlorotic leaves compared to green leaves. When the soil producing green and chlorotic plants was analyzed, it was found that total soil Fe levels were higher for green control plants than chlorotic control plants. This increased level of total soil Fe was not reflected in the foliar analysis. There was no major distinction in foliar Fe levels between green and chlorotic tissue. Xylary sap pH and Eh were also recorded for silver maples growing in various solution cultures. Solution cultures were prepared to simulate various types of Fe stress capable of causing Fe chlorosis. Although the solution culture pH varied widely, xylary pH stayed relatively constant. Xylary Eh measurements maintained an even narrower "buffered" range. When pH and Eh were combined on a similar scale (pH+ pe), the xylary sap pe + pH was observed to stay in a narrow range even when solution pe + pH varied widely

Genetics evaluation of phosphorus utilization in tropical cowpea (Vigna unguiculata (L) Walp)

Genetics evaluation of phosphorus utilization in cowpea (Vigna unguiculata (L) Walp) was studied in a cross involving a tropically adapted genotype (IT90K-277-2) with a reported positive response to rock phosphate (RP) and a second genotype (IT89KD-288) that responds negatively to RP, using generation mean analysis of the parents, their F1, F2 and the two backcross generations. Highly significant differences among the six generations with respect to seed phosphorus (P) concentration and grain yield per plant were observed. The F1 progenies produced seeds with higher seed P concentration (0.31 mg/g) than the mid-parent value (0.27mg/g). Mean yield per plant in the F1(48.03g) that was significantly greater than the mid-parent value (28.85g) was also observed suggesting positive heterosis for the two traits. Backcrossing to both parents showed good convergence of genes on the recurrent parents. Possibility of transgressive segregation for seed P concentration and grain yield per plant in the F2 generation was also observed. Absence of significant reciprocal differences among individuals in the F1 and F2 populations suggested lack of maternal and cytoplasmic effects. Non-additive gene action (dominance and epistasis) made significant contributions to total genetic variations in both traits within the cross. Whereas seed P concentration was observed to be under polygenic control, number of genes for seed yield per plant was biased downward by epistasis. Observed narrow-sense heritability estimate (HN)) for seed P concentration of 50.51% and very low (0.040) expected genetic gain in the F3 over the F2 means suggested that although expected progress from selection could be lowered by non-additive gene effects, this trait could be transmitted to the offsprings of hybridization program with huge success, through backcrossing. Although, available soil P (6.03 – 8.09mg/kg) was observed to be below the critical level, phosphorus uptake in the F1 and the segregating generations was observed to be higher than what obtained in the parents to suggest that the progenies of a P-efficient x P-inefficient cross would be efficient in P utilization.Keywords: Generation mean analysis, Phosphorus uptake, Polygenes, Transgressive segregants, Tropical vigna

Iron and Zinc Deficiencies in Selected Calcareous Soils of Southern Utah

The response of field corn to iron and zinc fertilization was studied using a split plot experimental design in Millard County, Utah, in cooperation with the Utah State University Extension Agent and a local farmer. mainplot treatment applications consisted, on an acre basis, of (1) 5 t ons of sulfuric acid, (2) 1 ton sulfuric acid, (3) 1.8 tons gypsum, (4) check plot. Subplot treatments were (1) Fe at 5 lbs/Ac, (2) Zn at 10 lbs/Ac, (3) Fe and Zn at 5 and 10 lb / Ac, respectively, (4) check plot. The iron and zinc applications were essentially rendered unavailable by reactions of the applied iron and zinc with the highly calcareous soil matrix. Experimental variability and the relatively low rates of applied micronutrients combined to produce insignificant yield responses to micronutrient fertilization. Another study was conducted to predict the soil iron critical level. Five soils from Millard County, representing some of the soils low in iron and zinc, were selected for a greenhouse study. All five of the soils were equally divided into three groups and assigned one of three pretreatments. One- third of the soils were stressed by successive croppings with corn and oats. One-third of the soils were fertilized with Fe chelate and ZnSO4 at 5 ppm each as a pretreatment. And one-third of the soils did not receive a pretreatment. The pretreatments were designed to obtain a broader range of soil iron concentrations. After the pre treatments were completed on all of the soils, a randomized block experimental design was employed to measure potential yield increases in corn produced by the addition of Fe chelate . Two corn genotypes, an iron-efficient corn inbred (WF9) and an iron efficient corn mutant (Ysl/Ysl), were utilized in the gr eenhouse study. The treatments were (1) 5 ppm Fe chelate plus corn inbred WF9, (2) 5 ppm Fe chelate plus corn mutant Ysl/Ysl, (3) no Fe addition plus corn inbred WF9 , (4) no Fe addition plus corn mutant Ysl/Ysl. Significant yield responses to Fe fertilization were determined by an LSD statistical test . Generally, soils with a DTPA extractable iron level greater than 5 ppm did not respond to applied iron. Similar yield responses were obtained for the iron-efficient and ironinefficient varieties. A tentative critical level of DTPA extractable iron of 5 ppm was proposed for the calcareous soils of Millard County, Utah

Utah Science Vol. 49 No. 1, Spring 1988

2 THE BLUE ORCHARD BEE: AN ALTERNATIVE POLLINATOR OF APPLES P. Torchio The blue orchard bee could be the answer to a threatened honeybee shortage. 10 BEATING THE ODDS-IDENTICAL TWINS FOR CA TILE RESEARCH C. W. Arave, T. D. Bunch, C. H. Mickelsen and D. Purcell Methods of splitting embryos to obtain more identical twin calves will facilitate research and may eventually lead to techniques to clone embryos on a commercial scale. 17 IRON DEFICIENCY IN PLANTS: GENOTYPIC MODIFICATION OF SOIL FERTILITY J. H. Bennett, N. J. Chatterton, P. A. Harrison and W. R. Thornely A review of recent research concerning the factors that affect a plant\u27s susceptibility to chlorosis. 23 HELPING RUMINANTS GET MORE FROM LOW-QUALITY FORAGE R. D. Wiedmeier Feeding trials identified the characteristics of protein supplements that enabled cattle to make the best use of rations containing large amounts of low-quality forage