Morphology and Rubisco turnover characteristics of perennial ryegrass breeding populations after two and four cycles of divergent selection for long or short leaf length

2013 ◽  
Vol 64 (7) ◽  
pp. 687 ◽  
Author(s):  
Edith N. Khaembah ◽  
François Gastal ◽  
Serge Carre ◽  
Louis J. Irving ◽  
Philippe Barre ◽  
...  
Keyword(s):  
Perennial Ryegrass ◽  
Morphological Traits ◽  
Dry Matter ◽  
Leaf Length ◽  
Elongation Rate ◽  
Leaf Elongation ◽  
Plant Yield ◽  
Leaf Elongation Rate ◽  
Selection For ◽  
Leaf Appearance

Perennial ryegrass populations previously subjected to two or four cycles of selection for short or long leaf length were studied to determine the response of morphological traits to selection and interaction to determine yield. Measured morphological traits were leaf length, leaf appearance interval, ligule appearance interval, leaf elongation duration, leaf elongation rate, tiller number, tiller dry weight, and herbage dry matter. Additionally, Rubisco concentration during leaf development was measured to determine the association of Rubisco turnover with morphological characteristics and yield. Rubisco was measured and modelled as a three-parameter (D, peak Rubisco concentration; G, time of D; and F, curve width measure), log-normal curve. Leaf length, leaf elongation rate, tiller weight, and plant dry matter diverged after two cycles of selection and further divergence occurred, with these traits being, respectively, 35, 28, 53, and 61% greater in the long- than the short-leaved plants after four cycles of selection. Opposite trends were displayed by Rubisco turnover, with selection for long leaves co-selecting for increased Rubisco turnover time and selection for short leaves resulting in increased leaf Rubisco concentration. There was indication of coupling of leaf appearance with Rubisco turnover. Across populations, multivariate analysis indicated that plant yield was associated with Rubisco concentration rather than Rubisco turnover. The association between higher yield and lower Rubisco concentration could be targeted in the breeding of high-yielding, nitrogen-efficient forage grasses. Plant yield was mainly associated with increased leaf area, indicating that yield could be improved by selecting for longer leaves and faster rates of leaf expansion.

scholarly journals Morphogenetic characteristics of three Brachiaria brizantha cultivars submitted to nitrogen fertilization

2013 ◽  
Vol 85 (1) ◽  
pp. 371-377 ◽  
Author(s):  
Marcos F Silva ◽  
Edson M. V Porto ◽  
Dorismar D Alves ◽  
Cláudio M.T Vitor ◽  
Ignacio Aspiazú
Keyword(s):  
Nitrogen Fertilization ◽  
Leaf Blade ◽  
Elongation Rate ◽  
Leaf Elongation ◽  
Brachiaria Brizantha ◽  
Nitrogen Levels ◽  
Appearance Rate ◽  
Leaf Elongation Rate ◽  
Leaf Appearance Rate ◽  
Leaf Appearance

This study aims to evaluate the morphogenetic characteristics of three cultivars of Brachiaria brizantha subjected to nitrogen fertilization. The design was a randomized block in factorial arrangement 4x3; three cultivars of B. brizantha - Marandu, Piatã, Xaraés and four nitrogen levels - 0, 80, 160 and 240 kg/ha, with three replications. The experimental units consisted of plastic pots filled with 5 dm3 of soil. Thereupon the establishment fertilization, varieties were sowed directly in the pots, leaving, after thinning, five plants per pot. Forty-five days after planting, it was done a standardization cut at 10 cm tall. Nitrogen levels were distributed according to the treatments, divided in three applications. The morphogenetic characteristics were evaluated in three tillers per sampling unit and data were submitted to analysis of variance and regression. For all evaluated characteristics there was no interaction between factors cultivar and nitrogen levels, verifying only the effects of nitrogen on the variables leaf appearance rate and phyllochron. The dose 240 kg/ha of N corresponds to the greater leaf appearance rate. Cultivar Marandu shows the higher leaf blade: pseudostem and ratio of leaf elongation rate and elongation pseudostem, which favors higher forage quality.

Production of root axes and leaf elongation in perennial ryegrass in relation to dryness of the upper soil layer

1980 ◽  
Vol 95 (3) ◽  
pp. 533-538 ◽  
Author(s):  
A. Troughton
Keyword(s):  
Perennial Ryegrass ◽  
Shoot Growth ◽  
Soil Layer ◽  
Selection Criterion ◽  
Elongation Rate ◽  
Soil Environment ◽  
Leaf Elongation ◽  
Experimental Conditions ◽  
Leaf Elongation Rate ◽  
Subsequent Introduction

SUMMARYDuring a period without rainfall the upper layers of the soil may become dry whilst the lower layers provide sufficient moisture for the plant to continue growing. In experimental conditions simulating such a soil environment, new main root axes ceased to be produced by plants of perennial ryegrass. Shoot growth and leaf elongation rate were little affected during the first 2 weeks of the treatment. The subsequent introduction of moisture round the base of the plant resulted in the rapid production of new root axes and increase in the leaf elongation rate. Although there was considerable intra-varietal genetic variation in the rate of development of new root axes and leaf elongation after wetting it is concluded that this would be of doubtful value as a selection criterion.

Genetic variability for leaf development in perennial ryegrass populations

1996 ◽  
Vol 76 (1) ◽  
pp. 113-118 ◽  
Author(s):  
L. Hazard ◽  
M. Ghesquière ◽  
C. Barraux
Keyword(s):  
Genetic Variability ◽  
Perennial Ryegrass ◽  
Natural Populations ◽  
Leaf Length ◽  
Divergent Selection ◽  
Leaf Elongation ◽  
Genetic Progress ◽  
Leaf Morphogenesis ◽  
Heritable Trait ◽  
Selection For

In perennial ryegrass (Lolium perenne, L.), leaf length is a highly heritable trait likely to respond to both natural and artificial selection. The genetic variability of components of leaf morphogenesis of perennial ryegrass was studied in 2 populations obtained from two cycles of divergent selection for lamina length, in 42 natural populations, and in forage and turf cultivars. The genetic progress in the two branches of the divergent selection was accompanied by a significant change in the leaf elongation rate, whereas the phyllochron and the leaf elongation duration remained relatively unchanged. The forage cultivars were not morphogenetically different from the natural populations, and hence progress for yield under infrequent cutting could be made by selection for long-leaf populations. Turf cultivars, however, were morphogenetically different from natural populations. Turf cultivars had small leaves with short sheaths and laminae. The population resulting from the selection for short leaf had laminae as long as those of turf cultivars but with longer sheaths.

scholarly journals Growth Responses of Lolium perenne L. to Trinexapac-ethyl

HortScience ◽  
1998 ◽  
Vol 33 (7) ◽  
pp. 1200-1202 ◽  
Author(s):  
E.H. Ervin ◽  
A.J. Koski
Keyword(s):  
Lolium Perenne ◽  
Perennial Ryegrass ◽  
Acid Ethyl Ester ◽  
Elongation Rate ◽  
Tiller Number ◽  
Growth Chamber ◽  
Root Mass ◽  
Growth Responses ◽  
Leaf Elongation ◽  
Leaf Elongation Rate

A growth chamber and a greenhouse study were conducted to determine if successive applications of trinexapac-ethyl (TE) to developing perennial ryegrass (Lolium perenne L.) plants would reduce leaf elongation rate (LER) while increasing tiller number and root mass. Growth parameters measured were LER, tiller number, and root mass. In the growth chamber, developing perennial ryegrass plants were sprayed twice with TE at 0.24 kg·ha-1 a.i. at 20 and 40 days after emergence. Leaf elongation rate was reduced by ≈35% following two applications of TE in both growth chamber experiments. This treatment increased the number of tillers per plant in the growth chamber at 60 days after emergence and in the greenhouse at 150 days after emergence, but had no effect on root or shoot mass in either location. Multiple applications of TE to developing perennial ryegrass turfs may favor quicker establishment in terms of tillering, while substantially reducing mowing requirement. Chemical names used: 4-cyclopropyl-α-hydroxy-methylene-3,5-dioxo-cyclohexanecarboxylic acid ethyl ester (trinexapac-ethyl).

scholarly journals The growth dynamics in Brachiaria species according to nitrogen dose and shade

2011 ◽  
Vol 40 (2) ◽  
pp. 270-276 ◽  
Author(s):  
Domingos Sávio Campos Paciullo ◽  
Priscila Beligoli Fernandes ◽  
Carlos Augusto de Miranda Gomide ◽  
Carlos Renato Tavares de Castro ◽  
Fausto de Souza Sobrinho ◽  
...  
Keyword(s):  
Leaf Blade ◽  
Stem Elongation ◽  
Growth Dynamics ◽  
Elongation Rate ◽  
Leaf Elongation ◽  
Light Reduction ◽  
Appearance Rate ◽  
Leaf Elongation Rate ◽  
Leaf Appearance Rate ◽  
Leaf Appearance

It was studied the effects of shading (0, 36 and 54%) and of four nitrogen doses (0, 50, 100 and 150 mg N/dm³ of soil) on the morphogenetic traits and on the tillering of grasses of Brachiaria genus (B. decumbens, B. ruziziensis and B. brizantha cv. Marandu and cv. Xaraes), cultivated in pots with 5 kg substrate. It was used a complete random design, in a 3 × 4 × 4 factorial scheme with three replications. Nitrogen promoted increase in leaf appearance rate and in average leaf blade length, whereas shading increased stem elongation rate. Leaf elongation rate and tillering varied with the interaction among shading percentages and nitrogen doses. Shading increased response efficiency of leaf elongation rate to nitrogen doses, but reduced for tillering, evidencing priority existing tillering growth in detriment to appearance of new tillers when there is light restriction for the plants. Phenotypic adjustments, in response to light reduction, indicate that the studied grasses present tolerance to moderate shading.

scholarly journals MORFOLOGIA FOLIAR DE SORGO SACARINO CULTIVADO EM DIFERENTES ESPAÇAMENTOS ENTRELINHAS E ÉPOCAS DE SEMEADURA

2018 ◽  
Vol 17 (1) ◽  
pp. 63
Author(s):  
ANDRIELI HEDLUND BANDEIRA ◽  
SANDRO LUIS PETTER MEDEIROS ◽  
BEATRIZ MARTI EMYGDIO ◽  
JEAN CECCHIM BIONDO ◽  
LINEU TRINDADE LEAL
Keyword(s):  
Sorghum Bicolor ◽  
Sweet Sorghum ◽  
Block Design ◽  
Shoot Elongation ◽  
Elongation Rate ◽  
Leaf Elongation ◽  
Sowing Time ◽  
Leaf Elongation Rate ◽  
Line Spacing ◽  
Sorghum Genotypes

RESUMO - O objetivo deste trabalho foi avaliar as características morfogênicas do colmo principal de genótipos de sorgo sacarino, em diferentes espaçamentos entrelinhas e épocas de semeadura. O experimento foi conduzido em Santa Maria-RS, em delineamento experimental de blocos ao acaso em esquema trifatorial (2x2x3), com dois genótipos de sorgo sacarino (BRS 506 e Fepagro 19), dois espaçamentos entrelinhas (0,50 m e 0,70 m) e três épocas de semeadura (outubro, novembro e dezembro), quatro repetições e dois anos de cultivo. Foram avaliadas a taxa de alongamento das folhas, o número final de folhas no colmo, a taxa de surgimento de folha, filocrono e taxa de elongamento de colmo. As variáveis não apresentaram interação tripla significativa entre genótipo, espaçamento de entrelinhas e época de semeadura. O genótipo BRS 506 apresentou número de folhas acumuladas, taxa de alongamento de folhas nas épocas de semeaduras constante. O atraso na época de semeadura resulta em menor número de folhas acumuladas e taxa de elongação do colmo para o Fepagro 19. O filocrono para o espaçamento entrelinhas 0,70 m é inferior ao de 0,50 m. Os genótipos estudados estão aptos para a produção na região, desde que a semeadura ocorra no mês de outubro. Palavras-chave: alongamento foliar, filocrono, graus-dia, índice Haun, Sorghum bicolor. LEAF MORPHOLOGY OF SWEET SORGHUM CULTIVATED IN DIFFERENT ROW SPACINGS AND SOWING DATES ABSTRACT - The objective of this work was to evaluate the morphogenic characteristics of the main stem of sweet sorghum genotypes in different spacing between lines and sowing times. The experimental was carried out in a randomized complete block design in a trifactorial scheme (2x2x3), with two sweet sorghum (BRS 506 and Fepagro 19), two spacing between lines (0.50 m and 0.70 m) and three sowing seasons (October, November and December), four replications and two years of cultivation. The leaf elongation rate, the final number of leaves in the stem, the leaf appearance rate, phyllochron and shoot elongation rate were evaluated. The variables did not present significant triple interaction between genotype, spacing between rows and sowing time. The genotype BRS 506 presented a number of accumulated leaves, leaf elongation rate at constant sowing times. The delay in sowing seasons results in a lower number of accumulated leaves and the elongation rate of the stem for genotype Fepagro 19. The phyllochron for the 0.70 m line spacing is less than 0.50 m. The genotypes studied are suitable for production in the region, as long as sowing occurs in October.Keywords: leaf elongation, phyllochron, degree-days, Haun index, Sorghum bicolor.

scholarly journals Developmental genetics of leaf formation in Lolium: 1. Basic Patterns of Leaf Development in L. Multiflorum and L. Perenne

1967 ◽  
Vol 9 (2) ◽  
pp. 233-245 ◽  
Author(s):  
K. J. R. Edwards
Keyword(s):  
Lolium Multiflorum ◽  
Leaf Size ◽  
Repeated Measurements ◽  
Developmental Genetics ◽  
Initial Growth ◽  
Leaf Elongation ◽  
Leaf Formation ◽  
Selection For ◽  
Leaf Appearance ◽  
Rate Of Leaf Appearance

1. Repeated measurements on the growth of individual leaves in seedlings and young plants of ryegrass combined with dissections of the apex of the shoot and of very young leaves have shown that the basic pattern of leaf formation is very similar in Lolium multiflorum and L. perenne.2. The initial growth rate of a leaf primordium is low but increases suddenly at a point when the primordium is somewhat longer than the apex and about 1 mm. in length. After this transition, which I have called the unfolding of the leaf, the rate of elongation is faster and more or less linear until the leaf is nearly mature.3. The time of unfolding of a leaf is very closely associated with the time of maturity of the next older leaf on the same side of the apex. Thus a leaf ceases growth when the next younger leaf immediately above it starts elongating rapidly, though which is cause and which is effect is it not possible to say.4. This close relationship between duration of leaf elongation and rate of unfolding of successive leaves holds for both species in two seasons. It leads one to predict that selection for increased leaf size, in so far as it is a result of greater duration of leaf elongation, is likely to be accompanied by a slower rate of leaf appearance, and conversely that selection for rate of leaf appearance is likely to result in smaller leaves.

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