Effect of sowing date and variety on main shoot leaf emergence and number of leaves of barley and wheat

Abstract

Rate of leaf emergence and number of leaves was measured on nine varieties of wheat and nine varieties of barley on four sowing dates in each of two years. Number of leaves declined the later the plants were sown, except for the February or March sowing when the number of leaves increased in the winter varieties. There were differences between varieties and a strong variety x sowing date interaction, which was probably due to differences in vernalisation response. The rate of leaf emergence was faster the later the sowing date and there were differences between varieties. Analysis by regression of number of leaves on accumulated temperature showed that the rate was up to 80 per cent faster in the last sowing, compared with the first. Differences of up to 18 per cent were found between varieties, but there was little or no interaction with sowing date. Leaves of barley emerged more quickly than those of wheat. There was a correlation between rate of leaf emergence and rate of change of daylength at the time of plant emergence, similar to that found by other workers. There was evidence that the base temperature varied with date of sowing. Additional key words : Vernalisation, accumulated temperature, rate of change of daylength, base temperature. RÉSUMÉ Effet de la date de semis et de la variété sur le rythme d'apparition des feuilles du brin-maître et leur nombre total chez l'orge et le blé. La vitesse d'apparition des feuilles et leur nombre ont été observés pour 9 variétés de blé et 9 variétés d'orge et pour 4 dates de semis au cours de 3 années successives. Le nombre final de feuilles diminue lorsque les dates de semis sont de plus en plus tardives, sauf pour le semis de février ou de mars pour lequel le nombre de feuilles est plus élevé chez les variétés d'hiver. On constate des différences entre variétés ainsi qu'une forte interaction variété x date de semis, qui sont probablement liées à des différences de sensibilité à la vernalisation. La vitesse d'apparition des feuilles augmente pour des semis plus tardifs et varie entre variétés. L'analyse, par régression linéaire, des relations entre le nombre de feuilles et les sommes de température accumulées montre une plus grande vitesse d'apparition des feuilles, de l'ordre de 80 %, pour le semis le plus tardif par rapport au plus précoce. Les différences entre variétés vont jusqu'à 18 %, mais l'interaction entre la date de semis et la variété est faible à nulle. Le rythme d'apparition des feuilles est plus rapide chez l'orge que chez le blé. Ce rythme est corrélé à la vitesse de changement de la durée du jour au moment de l'apparition du pied, selon une relation comparable à celle constatée par d'autres auteurs. On montre que la température de base (ou seuil) varie selon la date de semis. Mots clés additionnels : Vernalisation, température accumulée, vitesse de changement de la durée du jour, température de base.

Simulation of wheat ontogenesis. I. Appearance of main stem leaves in the field

“…(2) and (3) is expected not to be too far from the percentage increase in phyllochrone time measured by Kirby et al (1985) in the field. It can be calculated by fitting Eq.…”

“…The model is tested by means of both original and published field experiment data. MODEL DEVELOPMENT Kirby et al (1985) sowed Norman winter wheat in the field at Cambridge, England (Latitude 52"11fN), on 4 dates during the season 1980-81. Leaf appearance measurements of different sowings overlapped for certain periods so that it is possible to compare the leaf appearance rates of different crops.…”

Estimativa do filocrono em calêndula

“…Diferenças de filocrono para um mesmo genótipo em diferentes épocas de plantio já foram relatados em batata (PAULA et al, 2005), em meloeiro (BAKER & REDDY, 2001) e em distintas semeaduras de trigo, cevada e pastagens (FRANK & BAUER, 1995;KIRBY, 1995). ELLIS & RUSSEL (1984), KIRBY et al (1985) e BAKER et al (1986 verificaram que em trigo há efeito da época de semeadura na taxa de aparecimento foliar, indicando que, à medida que a semeadura é mais tardia, a soma de graus-dia requeridos para a emergência de uma folha é menor. A variação do filocrono da calêndula em diferentes épocas de semeadura pode estar relacionada com fatores ambientais como o fotoperíodo e a temperatura do ar.…”

Leaf development in two-row spring barley under long-day and short-day field conditions

“…and barley from seedling emergence to the appearance of the flag leaf (Kirby et al 1982;Kirby 1985;Kirby et al 1985;Kirby and Perry 1987; Bauer et al 1988; Cao and Moss 1989;van Oosterom and Acevedo 1992;Kaveeta 1993;Jedel and Helm 1994;Slafer et al 1994;Kernich et al 1995b; Sharratt 1999;Kamali and Boyd 2000;Juskiw et al 2001;Juskiw and Helm 2003).…”

“…and barley from seedling emergence to the appearance of the flag leaf (Kirby et al 1982;Kirby 1985;Kirby et al 1985;Kirby and Perry 1987;Bauer et al 1988;Cao and Moss 1989;van Oosterom and Acevedo 1992; rather than linear. There is evidence for non-ontogenetic reasons for a bilinear response where a change in phyllochron may occur between leaves 6-8 (Jamieson et al 1995;Slafer and Rawson 1997;Miralles and Richards 2000;Miralles et al 2001).…”