Effects of growth stage, leaf position and temperature on adult‐plant resistance of wheat infected by Puccinia recondita f.sp. tritici

Abstract

Growth stage, leaf position and temperature effects on components of resistance to Puccinia recondita f sp. tritici in wheat {Triticum aestivum) were studied. Inoculation of Era, GlenJea, Sinton and RL6044 plants at five growth stages showed that latent period increased and uredinium numbers decreased as each adult-plant-resistant wheat matured. Growth stage had httle effect on latent period in the susceptible cultivar Morocco. No significant differences in latent period determined on the flag, flag -1 and fiag -2 leaves of the same plant were observed for Era, Glenlea and RL6044. However, leaf age should be considered in assessing adult-plant resistance because the latent period of P. recondita f.sp. tritici in flag leaves of Sinton was shorter than that determined for the flag-1 and flag -2 leaves, Fewer uredinia developed on the flag -2 leaf o{ Glenlea than on the fiag leaf. The latent period of leaf rust in Era, Glenlea, RL6044and Morocco was significantly longer at 15 C than at 21"C, but temperature did not affect Sinton \o the same degree. Uredinium size was a sensitive criterion of adult-plant resistance. Uredinium development in line RL6044 was significantly restricted at 15 C, but uredinia on Era, Glenlea and Sinton at 15 C were as large as those at 2r C. On the susceptible Morocco uredinia were larger at 15Cthanat2i C.

The phenotypic expression of QTLs for partial resistance to barley leaf rust during plant development

“…The pictures were taken 228 h after inoculation (hai) in the Wrst leaf, 302 hai in the fourth leaf and 372 hai in the Xag leaf, respectively parent (L94) was less prolonged by advanced growth stages than that in the partially resistant cultivar Vada (Fig. 1), which is in accordance with the Wnding of Pretorius et al (1988) in wheat-wheat leaf rust interaction.…”

Age-Related Resistance in Arabidopsis Is a Developmentally Regulated Defense Response to Pseudomonas syringae

“…The relationship between plant age and disease resistance has been investigated in many plant-pathogen systems (Bateman and Lumsden, 1965; Griffey and Leach, 1965;Hunter et al, 1977;Lazarovits et al, 1981;Ward et al, 1981;Miller, 1983; Chase and Jones, 1986;Reuveni et al, 1986;Pretorius et al, 1988;Koch and Mew, 1991; Chang et al, 1992;Heath, 1993;Rupe and Gbur, 1995). Some plants become more susceptible to certain pathogens as they develop (Miller, 1983); however, susceptibility decreases with increasing leaf age in the rice/ Xanthomonas campestris pv oryzae (Koch and Mew, 1991) and rice/ Pyricularia oryzae (Roumen et al, 1992) interactions.…”

“…In contrast, older plants (both young and mature leaves) display increased resistance in the wheat/ Puccinia recondita f.sp. tritici (Pretorius et al, 1988) and tobacco/ Peronospora tabacina (Reuveni et al, 1986) interactions. When older leaves/plants display increased resistance or reduced susceptibility to pathogens, this form of resistance often is referred to as age-related resistance (ARR).…”

A Decision-support Model Based on Agro-environmental Data for the Economic Chemotherapy of Leaf Rust on Winter Wheat in Mississippi

“…tritici is determined in a certain region (Khan and Ilyas, 1997). Air temperatures (max/min/ave), rainfall and relative humidity, have already been reported to influence leaf rust development (Eversmeyer et al, 1988;Hyde, 1982;Pretorius et al, 1988;Tomerlin et al, 1984). In these studies inclusion of eleven environmental variables resulted in increased explanation of variability in leaf rust development.…”

“…Weekly averages of temperatures (max/min/ave) and rainfall in our studies explained 95 and 65 percent of the variability in disease development during 1992 and 1993, respectively. Temperature affects not only survival, latent period, infectious period, sporulation of the leaf rust fungus (Eversmeyer et al, 1973;Hyde, 1982;Pretorius et al, 1988;Tomerlin et al, 1984) but also the expression of resistance in the host (Hyde, 1982). Wind velocity, speed and direction affects the spore dislodge, dispersal, dissemination and landing.…”