Length Of First Internode Research Articles

Growth and morphology of spring wheat ( Triticum aestivum L.) culms and their association with lodging: effects of genotypes, N levels and ethephon

Lodging behavior and morphological characters of 12 spring wheat ( Triticum aestivum L.) genotypes (four Indian cultivars and eight Mexican cultivars/CIMMYT advanced lines) were studied under disease free condition with different N rates (180, 240 and 300 kg ha −1), and at 300 N, with ethephon (480 g ha −1) application at CIMMYT (Centro Internacional de Mejoramiento de Maı́z y Trigo), near Ciudad Obregon, Sonora, Mexico, during 1997–1998 and 1998–1999. In both years, the crop lodged, mainly by buckling or bending of the culms, 25–30 days after anthesis. Ethephon application at DC 38 prevented lodging and was associated with reduction in plant height (10.2%), peduncle length (14.2%), length of third internode (8.6%). It also simultaneously increased tillers m −2 (9.1%), stem wall thickness for the first (4.3%), second (6.3%) and third (8.1%) internodes and peduncle (3.6%) when compared at the same N level. Varietal differences in lodging behavior were significant during both years. The lodging tolerant genotype, Baviacora 92, had 31.9, 34.0, 40.7 and 34.1% larger diameter for the first, second, third internodes and peduncle, respectively, when compared to HD 2329, one of the most lodging susceptible genotypes. Furthermore, Baviacora 92 had first, second, third internode and peduncle stem walls that were also 31.7, 33.5, 35.4 and 37.1% greater, respectively, than Pavon 76, which had the thinnest stem walls. Genotypic correlations were better than phenotypic correlations, which suggested that environmental effects did not reinforce the genotypic effects rather they weakened them. Tillers m −2 correlated ( r=0.89, P<0.01) significantly positively while stem diameter and wall thickness correlated significantly negatively with lodging score. Diameter of different internodes including the peduncle, weight per stem and spike also correlated significantly negatively with tillers m −2. Simple linear regression explained that 79% of the variation in lodging score could be due to tillers m −2 and 49–65% due to diameter of different internodes. The best sub-set of the regression showed that number of tillers m −2 and/or stem diameter of internodes were the key variables when deciding two or three important characters for selecting for varieties with lodging resistance. Three variables such as stem diameter of first, second internode and length of first internode or tillers m −2, height and length of stem or tillers m −2, stem diameter of first, second internode together explained about 89–91% of the variation in lodging score. Therefore, it was suggested that selection for lodging resistant cultivars should emphasize larger stem diameter and wall thickness of basal internodes and fewer tillers per unit area with heavy spikes.

Brushing and Temperature Control Transplant Growth of Float-irrigated Bell and Jalapeno Pepper

Experiments were conducted at the North Carolina State Univ. Phytotron facility in late Summer and Fall 1996. Bell and jalapeno pepper were grown in polystyrene flats using continuous float irrigation. Using DIF (the difference between day and night temperatures), three temperature treatments consisting of positive (+DIF), zero (0DIF), and negative (–DIF) DIF were assigned to three growth chambers. DIF treatments were imposed in each chamber for only the first 2 hr after lights were turned on. Half of the plants in each chamber were brushed twice a day. Height was affected by cultivar, brush treatment, DIF treatment, and all combinations of the three treatments at all sampling dates. Jalapeno pepper experienced greater height reductions due to DIF or brushing treatment than bell pepper. Shoot fresh weight was reduced by brushing at all sampling dates, but DIF was less effective. Length of first internode was influenced by brush and DIF treatments, while leaf area was only affected by brush treatment which caused reductions of 13% and 25 % in bell and jalapeno pepper, respectively, at 6 weeks after planting. Brushing increased pepper stem diameter. DIF had little effect on stem diameter but in combination with brushing effectively increased stem diameter over both cultivars.

Preliminary Studies on the Application of Gibberellic Acid to Cotton Seed and Seedlings1

SynopsisSignificant reduction in stand and, increase in seedling height occurred when seed were treated with gibberellic acid and planted in July. Soaking seed caused an increase in length and width of cotyledons. No differences in seedling emergence were found when seed were treated with dust formulations and planted in April. Spraying seedlings immediately after emergence significantly increased seedling height, size of cotyledons, and length of first internode, and significantly decreased size of second leaf.

Societies and Academies

DUBLIN. Royal Dublin Society, June 16.—M. J. Gorman and H. A. Lafferty: On a method of distinguishing the seedlings of Swedish turnip (Brassica napus L. var. napobrassica (L.) Reichb.) from those of broad-leaved rape (Brassica napus L. var. biennis (Schubl et Mart) Reichb.). Characteristic differences in the shape of the first foliago (‘rough’) leaf and the relative length of first internode are recognisable in the seedlings of these two plants in fourteen to twenty days from the time of sowing the seeds.—T. Dillon and Annie McGuinness: On alginic acid: its mode of occurrence and its constitution. Alginic acid cannot occur in the free state in seaweeds, since no carbon dioxide is evolved during the solution of the fronds of Laminaria in sodium carbonate. Dialysis of alginic acid prepared from fresh fronds gives rise to an increase in the ash-content. This suggests that in the plant the acid is combined with non-polar colloidal compounds of calcium and iron. Dry alginic acid has the formula (C6H8O6); but this is a lactone. The polymerising unit is not an anhydride as in the case of starch and cellulose but the complete acid C6H10O7. The units are therefore not pyranose or furanose rays; but open chains.—M. Grimes and A. J. Hennerty: A study of bacteria belonging to the sub-gonus Aerobacter. The paper describes two species of bacteria previously unknown. These have been named Aerobacter hibernicum and Aerobacter liquefaciens respectively.